[Federal Register Volume 91, Number 143 (Tuesday, July 28, 2026)]
[Proposed Rules]
[Pages 47193-47211]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-15204]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
50 CFR Part 223
[Docket No. 260722-0176; RTID 0648-XR127]
Endangered and Threatened Wildlife and Plants; 12-Month Finding
on a Petition To List the Smalltail Shark (Carcharhinus porosus) as
Threatened or Endangered Under the Endangered Species Act
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of 12-month finding and availability of a status review.
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[[Page 47194]]
SUMMARY: We, NMFS, have completed a comprehensive status review for the
smalltail shark (Carcharhinus porosus) in response to a petition from
the Center for Biological Diversity to list the species. After
reviewing the best scientific and commercial data available, including
the Status Review Report, we have determined that listing the smalltail
shark as a threatened or endangered species under the Endangered
Species Act (ESA) is not warranted.
DATES: This finding was made on July 28, 2026.
ADDRESSES: The petition, status review report, Federal Register
notices, and the list of references can be accessed electronically on
our website at https://www.fisheries.noaa.gov/species/smalltail-shark.
The peer review plan and charge to peer reviewers are available at
https://www.noaa.gov/information-technology/smalltail-shark-status-review-report.
FOR FURTHER INFORMATION CONTACT: Dr. Nick Farmer, NMFS Southeast
Regional Office, (727) 228-3855 or [email protected].
SUPPLEMENTARY INFORMATION:
Background
On October 31, 2022, we received a petition from the Center for
Biological Diversity to list the smalltail shark (Carcharhinus
porosus), or any distinct population segment (DPS) of the species, as
an endangered or threatened species under the ESA. On May 23, 2023, we
announced in the Federal Register that the petition presented
substantial information in support of the petitioned action and that we
would conduct a status review, and we solicited information from the
public to support our status review (88 FR 33075, May 23, 2023). We
also provided notice to jurisdictions \1\ in Central America and
northern South America and requested scientific and commercial data, as
well as information on any ongoing conservation efforts, regarding this
species. All relevant information is incorporated in the status review
report (Heublein et al., 2025) and in this 12-month finding.
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\1\ We use the term ``jurisdiction'' rather than ``nation,'' as
French Guiana is an overseas department of France.
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Listing Determinations Under the ESA
We are responsible for determining whether species are threatened
or endangered under the ESA (16 U.S.C. 1531 et seq.). To make this
determination, we first consider whether a group of organisms
constitutes a species under section 3 of the ESA, then whether the
status of the species qualifies it for listing as either threatened or
endangered. Section 3 of the ESA defines ``species'' to include any
subspecies of fish or wildlife or plants and any DPS of any species of
vertebrate fish or wildlife which interbreeds when mature (16 U.S.C.
1532(16)). Because the petition requested we list the taxonomic species
or any DPS of the species, we assessed if information was available to
list individual populations as DPSs.
Section 3 of the ESA defines an endangered species as ``any species
which is in danger of extinction throughout all or a significant
portion of its range'' and a threatened species as one ``which is
likely to become an endangered species within the foreseeable future
throughout all or a significant portion of its range'' (16 U.S.C.
1532(6) and (20)). Thus, we interpret an ``endangered species'' to be
one that is presently at risk of extinction. A ``threatened species,''
on the other hand, is not currently at risk of extinction, but is
likely to become so in the foreseeable future. In other words, the
primary statutory difference between a threatened and endangered
species is the timing of when a species is in danger of extinction,
either presently (endangered) or not presently but in the foreseeable
future (threatened). Additionally, as the definitions of ``endangered
species'' and ``threatened species'' make clear, the determination of
extinction risk can be based on either the range-wide status of the
species or the status of the species in a significant portion of its
range. A species may be endangered or threatened throughout all of its
range or a species may be endangered or threatened within a significant
portion of its range (SPR).
Section 4(a)(1) of the ESA requires us to determine whether any
species is endangered or threatened as a result of any of the following
five factors: (A) the present or threatened destruction, modification,
or curtailment of its habitat or range; (B) overutilization for
commercial, recreational, scientific, or educational purposes; (C)
disease or predation; (D) the inadequacy of existing regulatory
mechanisms; or (E) other natural or manmade factors affecting its
continued existence (16 U.S.C. 1533(a)(1)). Section 4(b)(1)(A) of the
ESA requires us to make listing determinations based solely on the best
scientific and commercial data available after conducting a review of
the status of the species and after taking into account conservation
efforts being made by any state or foreign nation or political
subdivision thereof to protect the species (16 U.S.C. 1533(b)(1)(A)).
Status Review
We convened a team of six agency scientists to conduct a status
review for the smalltail shark and prepare a report. The status review
team (SRT) comprised natural resource management specialists and
fishery biologists from the NMFS Southeast Regional Office, Office of
Protected Resources, and Southeast Fisheries Science Center (SEFSC).
The SRT members have expertise in shark life history and ecology,
population dynamics, fisheries management and stock assessment science,
and protected species management and conservation. The status review
report (Heublein et al., 2025) presents the SRT's professional judgment
of the extinction risk facing the smalltail shark but makes no
recommendation as to the listing status of the species. The status
review report was subjected to peer review as required by the Office of
Management and Budget Final Information Quality Bulletin for Peer
Review (M-05-03; December 16, 2004). The status review report was peer
reviewed by three independent specialists selected from the scientific
community with expertise in smalltail shark biology and ecology,
conservation and management and specific knowledge of threats to the
smalltail shark. The peer reviewers were asked to evaluate the
adequacy, appropriateness, and application of data used in the status
review as well as the findings based on those data. All peer reviewer
comments were addressed prior to finalizing the status review report
and are available online (see ADDRESSES).
We subsequently reviewed the status review report, its cited
references, and public and peer reviewer comments. Much of the
information discussed below on smalltail shark biology and ecology,
distribution and connectivity, density and abundance, threats, and
extinction risk is taken from the status review report. We have also
considered new information published subsequent to the completion of
the status review report. We have independently applied the statutory
provisions of the ESA, including evaluation of the factors set forth in
section 4(a)(1)(A)-(E) and protective efforts under section 4(b)(1)(A)
in making our determination that listing the smalltail shark as an
endangered or threatened species under the ESA is not warranted.
[[Page 47195]]
Life History, Ecology, and Status of the Petitioned Species
Taxonomy and Species Description
The taxonomy of the smalltail shark has been relatively stable
since it was described as Carcharias porosus (Ranzani 1839) based on a
male holotype collected in the western South Atlantic Ocean off Brazil,
although the species was later moved to the genus Carcharhinus. Junior
synonyms are limited to Carcharias (Prionodon) henlei (M[uuml]ller and
Henle 1838) and Carcharhinus cerdale (Gilbert in Jordan and Evermann
1898). Castro (2011a) provided a thorough history of the taxonomy of C.
cerdale and the confusion that surrounds its synonymy with C. porosus.
Presently, C. porosus is taxonomically accepted as a valid species.
Common names utilized for C. porosus vary throughout its range and
include the generic names caz[oacute]n and toyo and the more specific
common names smalltail shark (English), Atlantischer Zwerghai (German),
requin tiqueue (French), squalo codapiccola (Italian),
ca[ccedil][atilde]o-azeiteiro, ca[ccedil][atilde]o-junteiro, sicuri-
branco (Portuguese), tibur[oacute]n cuero duro, tibur[oacute]n gordito,
and tibur[oacute]n poroso (Spanish) (Applegate et al., 1979; Compagno
1984; Gadig 2001; Castro 2011b; Voight and Weber 2011).
Physical Appearance
The smalltail shark is a relatively small-bodied shark that lacks
an interdorsal ridge and has a nearly equilateral triangle shaped first
dorsal fin with coloration that is light brown to gray dorsally and
dirty white ventrally (Castro 2011b). Smalltail shark fins lack
distinctive marking or coloration. Smalltail sharks are thought to grow
no larger than 150 centimeters (cm) in total length (TL; i.e., the
length measured from the tip of the snout to the tip of the tail)
(Compagno 1984; Lessa and Santana 1998).
The smalltail shark is the sole species in the Carcharhinus genus
in the western Atlantic Ocean with a second dorsal fin originating
above the midpoint of the anal fin. However, species within the genus
Rhizoprionodon, often referred to as sharpnose sharks, share this
characteristic. Sharpnose sharks are morphologically similar to
smalltail sharks, often leading to confusion and misidentification even
among biologists. The primary characteristic that readily
differentiates a smalltail shark from a sharpnose shark is the relative
length of the labial furrows. A smalltail shark has a very short to
rudimentary upper labial furrow at both corners of its mouth that can
be difficult to detect, whereas all sharpnose sharks have conspicuous
and long labial furrows. Additionally, smalltail sharks have poorly and
minimally developed preanal ridges, whereas these structures are
elongated and easily recognizable in sharpnose sharks when the caudal
fin and peduncle are depressed dorsoventrally while keeping the trunk
static.
Distribution, Movements, and Habitat Use
The distribution of the smalltail shark is limited to the western
Atlantic Ocean, although at least one dubious record of a single
individual in the eastern Atlantic Ocean exists (Bennet 1830). Based on
authoritative sources, the range extends from at least S[atilde]o
Paulo, Brazil (approximately 25[deg] S latitude; Gadig 2001) in the
South Atlantic to coastal Mississippi (approximately 30[deg] N
latitude; Bigelow and Schroeder 1948) in the North Atlantic. Within the
western Atlantic Ocean, smalltail sharks are documented in multiple
countries and jurisdictions including Brazil, French Guiana, Suriname,
Guyana, Venezuela, Panama, Mexico, and the United States (Bigelow and
Schroeder 1948; Applegate et al., 1979; Garrick 1982; Kohler et al.,
1998; Mej[iacute]a Falla et al., 2007; Tavares and S[aacute]nchez
2012).
Within U.S. waters, smalltail sharks have been collected off Texas,
Louisiana, and Mississippi (Baughman 1943; Bigelow and Schroeder 1948;
Castro 2011b; Swift and Portnoy 2021). Several sources state that
smalltail sharks occur in the coastal waters of Florida (Heemstra
1965); however, this is likely attributable to the often-cited Briggs
(1958), who included smalltail sharks as part of the shark fauna in the
northern Gulf of America (GOA) \2\ and explicitly stated he assumed
this and other species, by virtue of proximity, likely extend into
Florida waters. According to a comment letter submitted by the Florida
Fish and Wildlife Conservation Commission in response to the 90-day
finding on the listing petition (88 FR 33075), a few recreational
landings of smalltail sharks were reported in Florida waters in 1995
and 1996, but ``the uncertainty for these landings are [sic] extremely
high'' given its rarity and possible confusion with the Atlantic
sharpnose shark (Rhizoprionodon terraenovae). No commercial landings
have been reported in Florida waters since 1986 (Florida Fish and
Wildlife Conservation Commission July 17, 2023). Since 2010, there have
been only six records of smalltail sharks in U.S. fisheries; of these,
five were biosamples from surveys off Louisiana and Texas and one was a
recreational landing record in a Texas creel survey. Length was
recorded for 47 smalltail sharks captured in U.S. fisheries in the
northern GOA between 1984 and 2021; 42 were likely adult smalltail
sharks (<65 cm TL). Of the five potential juvenile smalltail sharks,
all were estimated to be over a year old based on length (<40 cm TL)
with the exception of a 26 cm TL smalltail shark that was noted as a
possible misidentification. These data suggest smalltail sharks are not
using waters of the northern GOA as birthing or nursery habitat and are
also extremely rare in U.S. waters.
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\2\ Formerly Gulf of Mexico. Renamed pursuant to Executive Order
14172, and Secretary of the Interior Order No. 3423.
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Within the South Atlantic Ocean, smalltail sharks are documented in
coastal waters throughout Brazil, including the states of Amap[aacute],
Par[aacute], Maranh[atilde]o, Pernambuco, Sergipe, Bahia, and
S[atilde]o Paulo (Bigelow and Schroeder 1948; Garrick 1982; Gadig
2001). Smalltail sharks have been reported as far south as Uruguay and
Argentina (Menni and Lucifora 2007; Ni[oacute]n et al., 2016).
Throughout their range, smalltail sharks inhabit relatively shallow
continental shelf waters. Reported depths of occurrence range from
shallow littoral waters, often associated with mud substrate in
estuaries, bays, and river mouths (Castellanos 2010; Swift and Portnoy
2021), out to depths of at least 84 meters (m) (Gadig 2001). According
to Feitosa et al. (2020a), there is no age-based change in habitat use
and all life stages co-occur, with the exception of seasonal habitat
partitioning based on sex. Water temperatures associated with locations
of smalltail shark capture range from 22 to 30[deg] C (NMFS SEFSC
unpublished data (number (n)=6); Feitosa et al., 2020a (n=17); Swift
and Portnoy 2021 (n=1)). There is limited information available to
describe salinity ranges associated with individual catches of
smalltail sharks; however, data from 2 fisheries-independent surveys
[NMFS SEFSC unpublished data (n=6); Swift and Portnoy 2021 (n=1)]
conducted in U.S. waters reported salinities at the location of capture
ranging from 24 to 36. Two studies have reported incidental capture of
neonate or juvenile smalltail sharks in areas with reduced salinity,
such as river mouths and estuaries (n=1 in Castellanos 2010; n=1 in
Swift and Portnoy 2021). The only data source we are aware of that
measured dissolved oxygen at the location of capture indicated that
smalltail sharks (n=6) were captured in normoxic waters 4.0 milligrams
per liter
[[Page 47196]]
(mg/L) of oxygen and higher (NMFS SEFSC unpublished data).
Feitosa et al. (2020b) generated species distribution models for
smalltail sharks using historical catch data. Distribution models were
generated using a combination of four algorithms trained on
environmental data (water temperature, light at the bottom, and
dissolved oxygen) and species occurrence records. Suitable habitat for
the species tended to fall on continental platforms, with models
determining that the northern coast of South America provides the most
suitable habitat for smalltail sharks compared to the eastern coast of
South America and the GOA. Additionally, the species distribution
models indicated a larger predicted range than empirical observations
support, spanning from the mid-Atlantic East Coast of the United States
to southern Brazil. The Caribbean islands were not found to have many
suitable areas for smalltail shark habitat. Species occurrence records
further indicate that the northern coast of South America is the most
important area for the smalltail shark in terms of habitat suitability
and historical catch. Feitosa et al. (2020a) also used vertebra
microchemistry to argue that Brazil's northern coast (BNC) is an
essential habitat for the species because its whole life cycle can
occur in the area. Microchemistry suggests the presence of multiple BNC
birthing areas that have been used across decades. The coexistence of
adults born in areas with diverging biochemical signatures suggests a
single population. Historical catch records indicate a relatively
higher occurrence of neonates in these birthing areas and elemental
concentrations from vertebrae indicate that individuals are likely not
only birthed in these areas but spend their lifetimes in the BNC.
Diet and Feeding
Smalltail sharks are considered to be opportunistic predators that
feed on relatively small prey, primarily fishes but also invertebrates
(Cort[eacute]s 1999; Gadig 2001; Castro 2011b). Their diet is similar
to other small-bodied sharks within the family Carcharhinidae, such as
Atlantic sharpnose (R. terraenovae), blacknose (C. acronotus), and
finetooth (C. isodon) sharks in the western North Atlantic Ocean. Lessa
and Almeida (1997) examined the stomach contents of 684 smalltail
sharks off the coast of northern Brazil and determined that
approximately 80 percent of the species' diet consists of small
teleosts including those from the families Sciaenidae (drums and
croaker), Mugilidae (mullet), Engraulidae (anchovies) and Stromatidae
(butterfish). The authors noted a decrease in teleost prey through
ontogeny and observed that other elasmobranchs, most notably
Rhizoprionodon spp. (sharpnose sharks) and Dasyatis spp. (stingrays),
were found in the stomachs of adults. Compagno (1984) also reported
small elasmobranchs in the diet of smalltail sharks, including young
sphyrnids (hammerhead sharks). Based on seasonal abundance of prey
species, Lessa and Almeida (1997) determined that smalltail sharks are
opportunistic and feed on whichever prey are most abundant.
Age and Growth
Two studies have examined the age and growth of smalltail sharks.
Batista and Silva (1995) examined 257 vertebrae collected from
individuals captured in gillnets off northern Brazil. The authors did
not generate a growth model but did suggest that growth characteristics
for smalltail sharks are typical of those observed for other species in
the family Carcharhinidae. Lessa and Santana (1998) used direct aging
of vertebrae for 508 specimens also collected in northern Brazil and
concluded there was no difference in growth between females and males.
Their estimated growth coefficients were similar to those estimated for
larger species (e.g., dusky sharks, Carcharhinus obscurus) and lower
than those estimated for other small coastal shark species
(Cort[eacute]s 2002). Lessa and Santana (1998) noted that the lack of
samples from larger individuals may result in inaccurately slow
estimates of growth rate and maturation time for the species. Lessa and
Santana (1998) acknowledged potential bias in their estimated growth
parameters, potentially attributable to length-selective fishing
mortality. In particular, their estimate of theoretical age at size
zero (to), is relatively long at-3.40 yr and their estimate
of longevity is nearly 35 years, although the oldest directly aged
individual was just 12 years old. By comparison, the to
estimate for the similar-sized and phenotypically similar Atlantic
sharpnose shark (Rhizoprionodon terraenovae) is only -0.88 yr and
theoretical longevity is 9.5 years (Carlson and Baremore 2003).
Reproductive Biology
Like other species within the genus Carcharhinus, female smalltail
sharks are placentally viviparous (Sadowsky 1967; Lessa et al., 1999;
Castro 2011b). Male smalltail sharks are reported to mature between 70
and 80 cm TL, while females reach maturity at 65-85 cm TL (Compagno
1984; de Campos Santos et al., 1999; Gadig 2001; Castro 2011b). Both
sexes are reported to reach maturity at an age of 6 years (Lessa et
al., 1999), with generation time estimated between 7.9 and 9 years
(Cort[eacute]s 2002; Santana et al., 2020).
Lessa et al. (1999) reported that females in waters off northern
Brazil ovulate from July through September, indicating this is when
mating occurs in the region. However, several authors indicate
smalltail shark reproduction is asynchronous throughout its range;
although peaks exist, seasonality cannot be definitively described
(Castro 2011b). Gestation lasts for 10-12 months and size at birth is
approximately 30-40 cm TL with neonates being present in coastal waters
from June through October (Sadowsky 1967; Compagno 1984; Menni and
Lessa 1998; Lessa et al., 1999; Gadig 2001). The sex ratio of females
to males within each brood was observed to be 1:1, and brood size
ranges from 1 to 11 embryos with a reported mean of 5.94 young (de
Campos Santos et al., 1999; Gadig 2001). Lessa et al. (1999) found a
significant positive relationship between maternal body length and
brood size. Female smalltail sharks are thought to reproduce on a
biennial cycle based on limited observations of gravid females with
inactive ovarian follicles (de Campos Santos et al., 1999; Castro
2011b).
Population Structure and Genetics
There is limited available information on smalltail shark
population structure or genetics. Tavares et al. (2013) evaluated 50
samples obtained from the catches of the commercial fishing fleet based
in Bragan[ccedil]a, in the Brazilian state of Par[aacute]. This
geographically limited study found smalltail shark had the highest
levels of haplotype and nucleotide diversity in this region among the
four studied species, but the results of the neutrality tests were
inconclusive regarding recent population trends (i.e., all negative,
but insignificant). There were several conflicting findings within the
paper. They detected a unimodal distribution of pairwise differences in
the mitochondrial control region, a possible sign of population growth.
However, C. porosus lacked the high number of singletons and the
consistent statistical significance across all tests seen in Caribbean
sharpnose shark (R. porosus), which was also tested. In population
genetics, a unimodal curve without significant neutrality tests such as
observed by Tavares et al. (2013) is often treated as a false positive
or a signal too weak to confirm expansion, especially in the presence
of genetic bottlenecks (Ramos-Onsins and Rozas 2002).
[[Page 47197]]
Tavares et al. (2013) also analyzed diversity in the more variable
mitochondrial control region, which yielded conflicting results,
further complicated by concern about bias introduced by possible
mutational hotspots. For example, they reported reduced nucleotide
diversity, possibly due to reduced population sizes, but also reported
high haplotype diversity and indications of population growth based on
neutrality tests and pairwise differences. The authors raised concerns
about recombination events and mutational hotspots in the mitochondrial
control region contributing to homoplasy (a shared genetic trait not
inherited from a common ancestor) and consequent underestimation of
genetic diversity and divergence times because the hyper-variable sites
might be masking the accumulation of unique mutations. Ultimately,
Tavares et al. (2013) concluded that Cytochrome b results might better
reflect the species' genetic diversity. They reported an L-shaped curve
and insignificant neutrality tests (Tajima's D, Fu's Fs),
suggesting no population expansion.
Many aspects of the Tavares et al. (2013) experimental design would
be anticipated to bias estimates towards low diversity, including the
reliance on geographically limited and potentially biased fishery
dependent data collection (e.g., gillnets), the lack of comparative
samples from other parts of the species' range (e.g., Caribbean or
southern Brazil), and the reliance on mitochondrial DNA (which does not
capture male-mediated gene flow). Given these factors and the
conflicting findings within the paper regarding demographic expansion
and genetic diversity, it is difficult to draw conclusions from this
study.
Demography
Natural mortality for smalltail sharks was estimated from specimens
(n = 937) collected in gillnets from waters off Maranh[atilde]o state
in 1984-1987 using nine age-independent and two age-dependent methods
(Santana et al., 2020). Santana et al. (2020) provided an estimated
mean natural mortality rate for males and females combined of 0.261
year -1 (range: 0.116-0.329 year -1, standard
deviation (sd) = 0.770 year -1). Total mean mortality was
estimated to be 0.656 year -1 (sd = 0.519 year
-1), yielding a mean fishing mortality of 0.395 year
-1 and an exploitation rate of 0.602 year -1
(Santana et al., 2020). Santana et al. (2020) applied these estimates
in a demographic analysis, which suggested an annual decrease of 28
percent in the intrinsic population growth rate, resulting in a
population decline of more than 90 percent in only 10 years, and much
higher through the terminal model year of 2019.
In their demographic analysis of smalltail sharks collected in the
gillnet fisheries off the BNC, Santana et al. (2020) calculated a mean
finite population growth rate ([lambda]) for smalltail sharks of 0.902
year-1 (0.756-1.011 year-1), suggesting a
declining population with a mean generation time of 7.7 years (7.2-8.0
years), and juvenile and adult survival rates of 0.661
year-1 (0.628-0.701 year-1) and 0.206
year-1 (0.158-0.246 year-1), respectively. By
contrast, Cort[eacute]s (2002) explored the effects of uncertainty in
demographic traits for 41 populations of 38 species of sharks and
reported higher population growth rates (1.086 year-1),
generation times (8.4 years), and juvenile (0.582 year-1)
and adult (0.312 year-1) survival rates for smalltail
sharks. Subsequently, Cort[eacute]s (2016) presented an updated meta-
analysis of 65 shark species, estimating smalltail shark population
growth rate at 1.203 year-1 (1.097-1.437 year-1).
Farmer (2025) updated the Cort[eacute]s (2016) analysis for smalltail
shark using demographic parameters from Santana et al. (2020) and
estimated a population growth rate of 1.049 year-1 (0.881-
1.102 year-1); slightly lower than Cortes (2002) and Cortes
(2016) but still reflecting positive population growth potential in
five of six scenarios evaluated.
Status of the Population
Global and Regional Abundance Estimates and Trends
There is limited information on global and regional abundance for
the smalltail shark. Modeled catch probability distributions from their
reported range showed declines in smalltail sharks between the 1970s
and 2010s, with the greatest declines predicted along eastern South
America and throughout the GOA and, to a lesser extent, along the
northern coast of South America (Feitosa et al., 2020b). Notably,
modeled declines of smalltail sharks outside of the northern coast of
South America were based on extremely limited data, and the SRT was
unable to find empirical studies of global smalltail shark abundance
beyond these modeling estimates. While general trends in smalltail
shark abundance were reported based on anecdotal information, the SRT
was not able to locate any systematically collected data from
fisheries-dependent or independent sources.
Northern GOA
Smalltail sharks are relatively rare in the northern GOA as this
region represents the northernmost extent of their range (Bigelow and
Schroeder 1948; Compagno 1984; McEachran and Fechhelm 2005). Stewart
Springer (Shark Industries, Inc.) first reported, ``a nice series of
`cerdale' '' (a junior synonym of C. porosus) taken off Biloxi,
Mississippi in 1943. From 1969 to 2021, NMFS caught only a dozen
smalltail sharks off Alabama, Mississippi, Louisiana, and Texas in the
northern GOA using shrimp trawl and bottom longline gears (NMFS
unpublished data). As mentioned above, 47 smalltail sharks have been
captured and measured in U.S. fisheries in the northern GOA between
1984 and 2021. Since 1986, there have been no commercial landings and
only a few recreational landings (1995 and 1996) of smalltail sharks in
Florida waters (Florida Fish and Wildlife Conservation Commission July
17, 2023). Furthermore, Swift and Portnoy (2021) conducted an
elasmobranch essential habitat study off Texas and reported one
smalltail shark from Corpus Christi Bay, representing one of only a few
verified observations of this species in Texas waters (Baughman 1943;
Baughman and Springer 1950). Based on its rarity in this region, no
abundance trends could be identified.
Southern GOA
There is minimal available information on smalltail shark abundance
in the southern GOA. Fisheries monitoring or research is either lacking
or regional journals and reports are inaccessible (Bigelow and
Schroeder 1948; Compagno 1984; McEachran and Fechhelm 2005). A few
studies characterizing the gillnet and small-scale bottom longline
fisheries in the southern GOA from 1993 to 2012 reported that smalltail
shark catch represented 0.2-2.0 percent of the total catch in those
fisheries (Castillo-G[eacute]niz et al., 1999; P[eacute]rez-
Jim[eacute]nez and Mendez-Loeza 2015; P[eacute]rez-Jim[eacute]nez et
al., 2020). Since fishery-dependent shark catch data are scarce in the
southern GOA, Bravo-Zavala et al. (2022) used data-limited assessment
methods to determine the susceptibility, rebound potential, and
cumulative vulnerability of sharks and rays in the region. Bravo-Zavala
et al. (2022) found smalltail shark had moderate rebound potential
(0.04 to 0.08) relative to 13 other elasmobranch species in two of
three scenarios evaluated and consistently ranked higher than six other
shark species. Although the smalltail shark
[[Page 47198]]
had the lowest rebound potential among small coastal sharks, the
analysis utilized life history characteristics reported by Lessa and
Santana (1998) that the SRT did not consider robust, particularly when
compared to similarly sized species. These potentially biased growth
parameters, detailed in the Age and Growth section above, were used by
Bravo-Zavala et al. (2022) to estimate population growth coefficients
for smalltail sharks, and the resultant estimates were similar to those
for larger species (e.g., dusky sharks) as compared to similar-sized
smaller coastal shark species (Cort[eacute]s 2002; see Life History,
Ecology, and Status of the Petitioned Species section). Despite this
potential bias, smalltail sharks exhibited low to moderate cumulative
vulnerability to current gillnet and longline fisheries in the southern
GOA (Bravo-Zavala et al., 2022). The low documented catch rates of
smalltail sharks in the southern GOA fisheries support the low
cumulative vulnerability designation; however, fishers have indicated
the species was more abundant in waters off of Campeche, Mexico before
the 1990s (Bravo-Zavala et al., 2022). On the basis of limited
available information and primarily anecdotal reports of fishers, it is
possible that smalltail shark populations may have declined in the
southern GOA, but the information is inconclusive.
Honduras
Rojas et al. (2000) reported that in Honduran waters, C. porosus
represented 1 percent of commercial fisheries catch, indicating that
smalltail sharks are present in Honduran waters. The General Director
of Fisheries and Aquaculture also recently reported the majority of
shark species taken as bycatch in fisheries are members of the family
Carcharhinidae, including the smalltail shark (K. Alvarado personal
communication, July 25, 2023). This information is inadequate to
determine any trend for smalltail shark populations in Honduras.
Venezuela
Available information on the abundance of smalltail sharks in
Venezuelan waters is minimal. Kleijn (1974) described exploratory and
experimental shark fishing cruises on the South American continental
shelf from Venezuela to French Guiana from 1968 to 1970 and reported
that smalltail sharks were the most abundant species collected during
the study, making up nearly 45 percent of the catch. Kleijn (1974) did
not explicitly report smalltail shark catch by country but catch by
gear type and effort by country were provided, which we can use to
roughly infer relative abundance. For example, handlining accounted for
74 percent of all smalltail sharks caught in this study but was not
reported as a fishing method in use in Venezuela, suggesting the catch
of the species in Venezuelan waters was likely less than that of
Guyana, Suriname, and French Guiana. A shark nursery study conducted in
the Gulf of Venezuela during the mid-2000s collected only seven
smalltail sharks (2 percent of total catch), suggesting smalltail
sharks are not common in this region (Tavares and S[aacute]nchez 2012).
This was further supported by Marquez et al. (2019), who documented the
elasmobranch composition in the Sucre State artisanal gillnet and
longline fishery from 2016 to 2017, where smalltail sharks made up 3.1
percent of the elasmobranch catch.
Although smalltail sharks are primarily found in shallow coastal
waters, Arocha et al. (2002) reported catches of this species by tuna
and swordfish vessels off Venezuela from 1994 to 2000. They reported
that smalltail sharks made up 8.4 percent of the overall bycatch;
however, the reported maximum size of the captured sharks (range: 80-
150 cm fork length (FL)) exceeded the putative maximum size for
smalltail sharks (150 cm TL; Compagno, 1984). Therefore, the SRT
questioned whether some of these sharks may have been misidentified.
Trinidad and Tobago
Shing (2006) reviewed the shark species composition from a fishery-
independent survey conducted off Trinidad and Tobago from 1985 to 2000,
designed to mimic the artisanal gillnet fishery on the north and east
coasts where shark catches were highest. Smalltail sharks were the most
common shark species encountered in the survey, primarily represented
by immature sharks, but gravid female smalltail sharks represented a
substantial portion of the catch from the inshore artisanal fishery
from March to May (Shing 2006). We were not able to find any other
information regarding smalltail shark abundance in Trinidad and Tobago.
Guyana, Suriname, and French Guiana
As mentioned above, Kleijn (1974) conducted an experimental shark
survey off the South American continental shelf from Venezuela to
French Guiana from 1968 to 1970 and reported that smalltail sharks were
the most abundant species collected during the study, making up nearly
45 percent of the catch (n=2,040). Most of the smalltail sharks
(n=1,577, 77 percent) were caught during handline operations off French
Guiana, Suriname, and Guyana (Kleijn 1974). The number of smalltail
sharks caught by country was not reported, but the total catch relative
to effort suggests that smalltail sharks were relatively common in the
coastal waters of these three countries from 1968 to 1970. Since this
study, little shark research has been conducted in this region; as a
result, the species composition and abundance of coastal sharks in the
region is poorly understood. Kolmann et al. (2017) used
deoxyribonucleic acid (DNA) barcoding to determine the species most
commonly caught and consumed along the coastline of Guyana by sampling
sharks at fish markets. Smalltail sharks comprised 17.4 percent (n=32)
of the shark specimens examined, representing the second most abundant
shark species identified in the study.
Brazil
Most of the information available on smalltail shark population
abundance is from Brazil. Smalltail sharks are not targeted in
fisheries in this region but are caught as bycatch in gillnet,
longline, and trawl fisheries, which target various commercial species,
including mackerels, weakfish, and shrimp (Lessa et al., 1999;
Marceniuk 2020). The highest levels of bycatch occur along the BNC,
which includes the states of Maranh[atilde]o, Par[aacute], and
Arap[aacute] (Feitosa et al., 2020b; Santana et al., 2020). There are
indications the smalltail shark has suffered severe population declines
over the past few decades off the BNC; however, the quantitative data
underlying these conclusions is limited (Feitosa et al., 2020b). Lessa
et al. (2018) cites two studies (Stride et al., 1992; Morais, 2004)
claiming that trawl catch per unit effort (CPUE) had declined
approximately 85 percent, from 2.87 kg/hr in 1990 to 0.43 kg/hr in the
early 2000s. However, the SRT was not able to verify this decline, as
descriptions of the data were inconsistent with the cited literature,
and the SRT was unable to access the original data after multiple
attempts.
There has also been a notable change in the prevalence of smalltail
sharks in catches reported by artisanal fisheries in northern Brazil
over time. For example, smalltail sharks comprised 43-52 percent of the
shark species caught in the artisanal gillnet fishery in the 1980s
(Lessa 1997; Menni and Lessa 1998). A study investigating shark species
composition at local fish markets within the BNC region documented
smalltail sharks as the most common shark species in the early 2000s,
representing nearly 46.7 percent (57 of 122
[[Page 47199]]
individual sharks) of the specimens examined (da Silva Rodrigues-Filho
et al., 2009). However, the shark specimens that were sampled in this
study could not be attributed to specific fisheries, so comparisons
drawn between this study and artisanal gillnet catch from the 1980s
described above must be interpreted cautiously. More recent studies
conducted in the region from 2014 to 2018 reported that smalltail
sharks were the third most abundant species from markets and port
sampling, representing between 5.5 and 13.1 percent of the total
specimens examined (n=42 in Feitosa et al., 2018; n=98 in da Silva
Ferrette et al., 2019; n=1 in Martins et al., 2021). None of these
studies used comparable methods or were designed to investigate the
decline in smalltail sharks in fisheries over time. For example,
specimens were sampled at different times in different studies across
various fish markets across northern Brazil. Specimens were collected
from many different fisheries, including trawl, gillnet, and longline,
each with their own unique selectivity and catchability for the
species. Additionally, Brazil enacted harvest prohibitions on smalltail
shark beginning in 2014 (see Inadequacy of Existing Regulatory
Mechanisms), which may have reduced the number of smalltail sharks
brought into fish markets. Due to these inconsistencies in sampling
methods and the additional confounding factor of management
prohibitions, it is impossible to assign a quantitative value to the
magnitude of decline based on these data.
Batista and Silva (1995), while conducting an age and growth study
of juvenile smalltail sharks in Maranh[atilde]o coastal waters of the
BNC, did not find evidence of size-selective fishing. The authors
concluded that fisheries had not seriously affected the stock because
there was no specific fishery for smalltail sharks in the region and
bycatch data did not show a clear tendency for back-calculated lengths
to diminish with age class (i.e., ``Lee's phenomenon;'' Ricker 1975).
Lee's phenomenon suggests that faster-growing fish would be exposed to
size-selective fishing mortality sooner and die younger, where slower
growers would survive, meaning slower-growing fish would be over-
represented in the contemporary population. Batista and Silva (1995)
did not observe back-calculation bias in their samples, suggesting
selective fishing pressure was not taking place. Over two decades
later, Martins et al. (2018) conducted interviews with experienced
artisanal gillnet and longline fishers to describe shark catch over
time and the status of local stocks. The fishers reported that
smalltail sharks were once easily caught during the 1980s and 1990s in
the BNC but were now scarce and found only in deeper offshore waters
(Martins et al. 2018). The authors reported that fishers indicated that
smalltail shark is the species at the greatest risk of extinction in
Maranh[atilde]o waters (Martins et al., 2018).
Relative to the BNC, records of smalltail shark catches off
Brazil's central, southeast, and south coasts are less frequent;
however, there is some anecdotal evidence of decline. Gadig (2001)
states that data indicate smalltail sharks were abundant on the south
coasts of S[atilde]o Paulo in the 1960s, but catches there are now
uncommon.
The most direct explanation for declines in smalltail shark
populations is overexploitation. Santana et al. (2020) reports that
smalltail shark was the most abundant elasmobranch species in fisheries
off the BNC in the 1980s, but its population has been declining since
the 1990s. Most (90.6 percent) smalltail shark specimens (n=937)
collected with gillnets in the eastern BNC in the 1980s were juveniles
(<6 years old). Demographic analysis indicated mortality and
exploitation rates in the 2000s were 92.3 percent above the fishing
mortality rate corresponding to the population equilibrium threshold
(Santana et al., 2020). Santana et al. (2020) reported that the
combination of compromised recruitment of juveniles, overfishing, and
intrinsically low resilience (e.g., slow growth rate, late age of
maturity, and low fecundity) relative to other small coastal shark
species all contributed to model-estimated population declines. Santana
et al. (2020) predicted between a 77.1 percent to 99.9 percent decline
in abundance by 2011. Santana et al. (2020) also reported several
localized extinctions for the species in the northeastern and
southeastern regions of Brazil. However, Santana et al. (2020) also
predicted between a 49.5 percent to 94.2 percent decline in abundance
by 1997, which stands in contrast to the findings of Batista and Silva
(1995) discussed previously, which suggested fishing pressure was not a
concern for the species during the early 1990s.
A decline in the abundance of the smalltail shark in Brazil is
reported almost uniformly across disparate data sources. Given the
available information, the SRT was unable to estimate the magnitude of
the smalltail shark's abundance decline in Brazil in quantitative
terms. However, the SRT concluded the available information suggests
the population in Brazil has declined substantially based on the number
and consistency of local references reporting this conclusion and the
fact that at least a portion of these studies relied on quantitative
data.
Assessment of Extinction Risk
As noted previously, the ESA defines an endangered species as ``any
species which is in danger of extinction throughout all or a
significant portion of its range'' and a threatened species as ``any
species which is likely to become an endangered species within the
foreseeable future throughout all or a significant portion of its
range'' (16 U.S.C. 1532(6) and (20)). NMFS' implementing regulations
describe the ``foreseeable future'' as extending into the future as far
as we can make reasonably reliable predictions about the threats to the
species and the species' responses to those threats (50 CFR 424.11(d)).
On November 21, 2025, NMFS and the U.S. Fish and Wildlife Service
(USFWS) published a proposed rule that would slightly revise the
description of the foreseeable future to state that it ``extends only
so far into the future as the Services can reasonably determine that
both the future threats and the species' responses to those threats are
likely'' (90 FR 52607, November 21, 2025). The current and proposed
regulations instruct us to describe the foreseeable future on a case-
by-case basis, using the best available data and taking into account
considerations such as the species' life-history characteristics,
threat-projection timeframes, and environmental variability. The
current and proposed regulations also state that we need not identify
the foreseeable future in terms of a specific period of time. We
considered the proposed revision to this regulation and concluded that
our assessment of the extinction risk for the smalltail shark is the
same under either description of the foreseeable future.
For the assessment of extinction risk for the smalltail shark, the
SRT considered the ``foreseeable future'' to extend out approximately
25 years for the main identified threats of overutilization and
inadequacy of existing regulatory mechanisms and most other potential
threats. Given the species' life history (i.e., mean generation time
approximately 8 years and maximum age approximately 34 years), it would
likely take multiple generations for management actions to be reflected
in population status. Similarly, the impact of present threats to the
species could be realized in the form of noticeable population declines
within this time frame, as demonstrated in the available survey and
fisheries
[[Page 47200]]
data. The SRT also acknowledged that population recovery is likely
dependent on when a protective regulatory measure, such as a closure,
is implemented and enforced, and also the status of the population at
the time of the closure.
To assess the potential threat of warming seas and the increasing
frequency and intensity of extreme weather events, the SRT considered
these environmental shifts over a longer time horizon, extending out to
2100. The SRT determined that warming seas and increasing extreme
weather events could be reasonably expected through the year 2100,
albeit with increasing uncertainty in their magnitude through time;
however, the SRT could not reasonably determine how smalltail sharks
would respond to these environmental changes.
In analyzing the extinction risk of smalltail shark, the SRT
considered not only the current and potential threats impacting the
species' status but also the species' demographic status and
vulnerability. Thus, the SRT conducted an extinction risk analysis in
three parts: (1) demographic risk analysis, (2) threats assessment, and
(3) overall extinction risk analysis.
Demographic Risk Analysis
A demographic risk analysis is an assessment of the manifestation
of past threats that have contributed to the species' current status
and informs the consideration of the biological response of the species
to present and future threats. The SRT's demographic analysis assessed
demographic risk by considering a set of questions adapted from
McElhany et al. (2000). The SRT considered the best scientific and
commercial data available regarding four demographic characteristics
(i.e., abundance/trends, growth rate/productivity, spatial structure/
connectivity, and diversity) for the smalltail shark to evaluate how
these factors influence extinction risk for the smalltail shark. After
reviewing all relevant biological and commercial information for the
species, each SRT member assigned a ranking to each of the four
demographic factors. Risks for each demographic factor were ranked on a
scale of 1 (low risk) to 3 (high risk). Details about these risk
categories can be found in the status review report (Heublein et al.,
2025). This process helped the SRT integrate and summarize a large
amount of diverse information and served as a useful tool to help the
SRT organize the information and assist in the process for determining
overall risk of extinction for the species.
Abundance
There is minimal information on global and regional abundance
estimates for the smalltail shark. Although robust quantitative data
useful in exploring trends in population abundance are lacking,
available data from other sources (e.g., fish markets, interviews and
fisher surveys) and anecdotal accounts consistently indicate abundance,
or frequency of encounters, has declined significantly off Brazil since
the 1980s (Feitosa et al., 2018; Martins et al., 2018; da Silva
Ferrette et al., 2019; Martins et al., 2021). Modeled catch probability
distributions from their reported range predicted declines in smalltail
sharks between the 1970s and 2010s, with the greatest declines
predicted along eastern South America (approximately -50 percent) and
throughout the GOA (approximately -40 percent), and to a lesser extent,
along the northern coast of South America (approximately -10 percent;
Feitosa et al., 2020b). Notably, modeled declines of smalltail sharks
outside of the northern coast of South America were based on extremely
limited data, and we were unable to find empirical studies of global
smalltail shark abundance beyond these modeling estimates. Although
population declines are apparent across studies, there is substantial
uncertainty in the magnitude of decline.
Santana et al. (2020) performed demographic modeling based on 937
smalltail sharks caught between 1984 and 1986 during experimental
gillnet fisheries sampling off the Brazilian state of Maranh[atilde]o.
Santana et al. (2020) estimated theoretical population declines ranging
from 7 to 28 percent per year. There are important shortcomings in this
analysis and questions about the life history data used in the models,
given the magnitudes of decline predicted appear to be well above those
suggested by other studies.
Considering the ongoing threat of overutilization by artisanal
fisheries and the consistent reports of population decline, it is
likely the abundance of smalltail sharks in the core BNC region has
declined substantially since the 1980s. Data from regions outside of
the BNC are more limited and offer minimal insight into the species'
abundance. Anecdotal reports from fishers in Mexico and southern
Brazil, however, state that smalltail shark numbers are significantly
reduced from several decades ago (Gadig 2001; Bravo-Zavala et al.,
2022).
In contrast to the Santana et al. (2020) study results for
Maranh[atilde]o state in Brazil, studies conducted in other areas where
the species has been historically abundant (i.e., off the coasts of
southern Central America and other areas in northern Brazil) indicate
the smalltail shark continues to be a common species. For example, da
Silva Rodrigues-Filho et al. (2009) found smalltail shark to be the
most common shark species at the municipal fish market in
Bragan[ccedil]a and at the docks in Bacuriteua and Bragan[ccedil]a (in
the Brazilian state of Par[aacute]) between October 2005 and December
2006 (n=57/122). Feitosa et al. (2018) found smalltail shark to be the
third most abundant shark species in samples taken from BNC fish
markets (Amap[aacute] (n=48), Bel[eacute]m (n=26), Bragan[ccedil]a
(n=55), Vigia (n=13), Carutapera (n=14), Raposa (n=53), and Tutoia
(n=219)), appearing in 9.81 percent of samples. Similarly, da Silva
Ferrette et al. (2019) found smalltail shark to be the third most
common shark species in samples taken from BNC fish markets, appearing
in 98 (14 percent) of 700 samples taken from the states of Par[aacute]
(n=400) and Natal (n=300).
Following the completion of the Status Review Report, Coelho et al.
(2025) published the results of interviews with 314 fishers from across
the Maranh[atilde]o State coastline in the BNC conducted between
December 2019 and October 2020. Smalltail shark was the second most
abundant shark species, with 1,576 total fisher reports
(Reentr[acirc]ncias Maranhenses, n=684; Upaon A[ccedil]u, n=353; Foz do
Rio das Pregui[ccedil]as, n=539). Smalltail sharks were most commonly
caught by gillnet (approximately 90 percent of catch) in
Reentr[acirc]ncias Maranhenses; by gillnet (approximately 65 percent)
and longline (approximately 30 percent) in Upaon A[ccedil]u; and by
gillnet (approximately 55 percent), longline (approximately 20
percent), and beach seine (approximately 20 percent) in Foz do Rio das
Pregui[ccedil]as. Per fisher reports, smalltail shark were the third
most commonly caught shark in Reentr[acirc]ncias Maranhenses (3.58
4.34 sharks, N=191), the second most commonly caught shark
in Upaon A[ccedil]u (5.43 6.04 sharks, N=65), and the most
commonly caught shark in Foz do Rio das Pregui[ccedil]as (9.29 7.65 sharks, N=58).
While the SRT agreed smalltail shark abundance has very likely
decreased since the 1980s, the uncertainty associated with quantifying
the decline affected their rankings. Thus, while the available
abundance information indicates the smalltail shark is not presently at
a high risk of extinction, the majority of the SRT thought the
likelihood of declining abundance in the foreseeable future contributed
to the
[[Page 47201]]
species' extinction risk. Conversely, one SRT member considered
abundance to be a low demographic risk, based on the data uncertainty,
limited data available, and certain reports indicating that the species
is still commonly captured in the core of its range. Overall, the SRT
ranked abundance as a moderate risk to the extinction of the smalltail
shark.
We considered the SRT's findings and agree that although modeled
catch probability distributions from their reported range suggest
declines in smalltail sharks between the 1970s and 2010s (Feitosa et
al., 2020b), it is difficult to determine the magnitude of this
decline. Records in the northern GOA are too sparse to be conclusive
regarding any trend. Analyses for the southern GOA using the
potentially biased Lessa and Santana (1998) growth parameters suggests
low to moderate vulnerability to current gillnet and longline fisheries
in the southern GOA, a finding supported by low documented catch rates
(Bravo-Zavala et al., 2022). No information on a trend was available
for Honduras or Venezuela. Historically, smalltail sharks were the most
common species of shark encountered in gillnet surveys off Trinidad and
Tobago (Shing 2006) and in handline studies off French Guiana,
Suriname, and Guyana (Kleijn 1974), but given the lack of comparative
contemporary studies, no trend can be inferred for these countries.
Notably, smalltail sharks were the second most abundant shark species
identified in Guyana fish markets by Kolmann et al. (2017), suggesting
the species may still be reasonably abundant off that coast. Off
Brazil, where smalltail sharks are caught as bycatch in a variety of
fisheries (Lessa et al., 1999; Marceniuk 2020), the SRT was unable to
verify the large declines modeled by Santana et al. (2020). It is
possible the percentage of smalltail sharks encountered in fish markets
and port sampling declined between the 1980s-2000s (Lessa 1997; Menni
and Lessa 1998; da Silva Rodrigues-Filho et al., 2009) and 2014-2018
(Feitosa et al., 2018; da Silva Ferrette et al., 2019; Martins et al.,
2021); however, differences in observed abundance could also be
explained by differences in source fishery, sampling methodology,
overall study purpose, and the enactment of harvest prohibitions by
Brazil beginning in 2014.
We conclude that the smalltail shark is vulnerable to
overexploitation due to its coastal, shallow-water habitat and the
continued operation of largely unmonitored artisanal gillnet fisheries
and semi-industrial and industrial shrimp and general teleost trawl
fisheries in their range (Santana et al., 2020). While anecdotal
reports, limited studies, and models suggest a likely population
decline--with some estimates indicating a significant reduction off
Brazil since the 1980s--the absence of comparable and systematic long-
term studies makes it impossible to definitively quantify the extent of
this decline or evaluate contemporary abundance in the context of
extinction risk.
Growth Rate/Productivity
The majority of the available information on growth rate and
productivity in smalltail sharks is summarized by Santana et al.
(2020), who estimated low population growth rate and extremely low
survival rates in the BNC. However, the limited life history
information for the species likely contributed to these results being
more extreme than would be expected. Two age and growth studies are
available for this species, although only one provides growth curves
(Lessa and Santana 1998), and one was based mostly on juvenile
individuals (Batista and Silva 1995). The lack of data from larger
individuals may have greatly influenced the estimated age and
subsequent growth parameters for the species, with no data to anchor
the growth curves' upper limit. This results in a model that
overestimates theoretical maximum size (L[infin]). Maximum
age is calculated based on the time required to reach
L[infin], leading to an overestimate of lifespan which then
translates to pessimistic estimates of population growth potential. The
estimated growth coefficients for smalltail sharks are similar to those
estimated for slower growing larger species (e.g., dusky sharks) and
lower than those estimated for other small, coastal shark species
(Cort[eacute]s 2002). The lack of samples from larger individuals in
the Lessa and Santana (1998) study may have contributed to a
surprisingly low growth coefficient estimate, which, in turn, could
result in underestimates for individual and population growth rates.
Although smalltail sharks reproduce biennially (de Campos Santos et
al., 1999; Castro 2011b), there is limited reproductive information
available for the species by which we can further assess the species
productivity.
Population growth and mortality estimates provided by Santana et
al. (2020) suggested low recovery potential even in the absence of
fishing, although, as noted above, there were various shortcomings in
the modeling approach used. The SRT noted uncertainty in the growth
coefficients used to determine recovery potential. The growth model of
Lessa and Santana (1998) is the foundation for assumptions regarding
the apparent slow growth, late age at maturity, and low estimated
fecundity for the species that drive the conclusions of Santana et al.
(2020) and Bravo-Zavala et al. (2022) regarding the relatively low
productivity for this species when compared to other small, coastal
sharks.
There was no available information indicating that reproductive
traits have changed over time. The species does not exhibit trends in
demographic or reproductive and growth characteristics that portend
declines in per capita growth rate. As with other life history data,
the information available about reproductive traits is based on a
limited sample of adult smalltail sharks (Lessa et al., 1999).
Because the estimated population growth rate is unreliable, the SRT
could not be certain if the population growth rate is above or below
replacement and whether depensation is a risk factor. However, the SRT
felt that continued declines in abundance and evidence of overfishing
suggested population growth rates for smalltail sharks are likely below
replacement. Although there is currently little evidence of depensatory
processes in smalltail shark populations, the SRT indicated it was
likely that smalltail shark are at increased risk for negative impacts
due to depensatory processes in the foreseeable future.
Given the potentially high levels of harvest occurring along the
north coast of South America, and evidence of significant population
declines throughout the BNC (core range), the majority (four of six) of
SRT members found that current population growth and productivity rates
present a moderate risk to the species, significantly contributing to
its long-term extinction risk. Two SRT members, however, concluded that
growth rate and productivity were a low risk, primarily because of the
lack of conclusive evidence of population decline and the continued
presence of smalltail sharks across a broad geographic range.
We considered the SRT's findings and agree with their
characterization of the uncertainty regarding the population growth
rate for smalltail shark populations. Santana et al. (2020) calculated
a mean finite population growth rate ([lambda]) for smalltail sharks of
0.902 year-1 (0.756-1.011 year-1), suggesting a
declining population. As noted by the SRT, Cort[eacute]s (2002)
reported slightly higher population growth rates (1.086
year-1) for smalltail sharks. Additionally, Cortes (2016)
[[Page 47202]]
presented a meta-analysis of the intrinsic rate of population growth
(rmax) calculated by six different methods across 65 shark
species: (1) Myers et al. (1997)'s extinction risk equation, which was
intentionally misspecified to omit a cumulative survival term; (2)
Eberhardt et al. (1982)'s equation, a derivation of the Euler-Lotka
equation assuming constant adult survival and fecundity; (3) Skalski et
al. (2008)'s equation, a modification of Eberhardt et al. (1982) that
does not require estimates of longevity; (4) Smith et al. (1998)'s
rebound potentials, which incorporate density dependence through
increased pre-adult survival; (5) Niel and Lebreton (2005)'s
Demographic Invariant Method, which combines age-based matrix models
with allometric models; and (6) the traditional Euler-Lotka equation,
which is age-structured and uses age-specific survivorship. The Cortes
(2016) estimate of rmax for smalltail shark corresponds to a
[lambda] of 1.203 year-1 (1.097-1.437 year-1).
To further evaluate the productivity of smalltail shark
populations, we updated the analysis of Cortes (2016) with reproductive
parameters from Santana et al. (2020) to compute rmax for
smalltail shark (Farmer 2025). Cort[eacute]s (2016) used
rmax results from the Euler-Lotka equation (Method 6) to
define slow-growing (rmax <=0.05), medium-growing (0.05 <
rmax <=0.15), and fast-growing (rmax >0.15)
populations. Using updated reproductive parameters, we found the
smalltail shark median value for rmax for the Euler-Lotka
equation was 0.084, making it a medium-growing population following the
Cort[eacute]s (2016) criteria (Farmer 2025). Further, the median value
for rmax for smalltail sharks exceeded the median value for
medium-growing species evaluated by Cort[eacute]s (2016) in 5 of 6
methods evaluated. The updated rmax values correspond to a
[lambda] of 1.049 year-1 (0.881-1.102 year-1);
slightly lower than Cortes (2002) and Cortes (2016) but still
reflecting positive population growth potential for 5 of 6 methods
evaluated. A lambda value greater than one is a good indicator for a
species' health and resilience. It suggests that the birth rate and
survival rates are sufficient to overcome the death rate, leading to a
growing population. The relatively high rmax for smalltail
shark suggests a greater capacity for a population to increase its
numbers under ideal conditions, such as low density and abundant
resources (Begon et al., 2006). Smalltail shark populations may be able
to withstand higher levels of exploitation relative to less productive
shark species because their rapid reproductive rates and shorter
generation times enable them to compensate for individuals removed
through harvesting (Myers and Mertz 1998).
We agree with the SRT that analysis of the smalltail shark
population's growth and recovery potential is hampered by significant
data limitations, particularly regarding life history traits and a lack
of comprehensive, up-to-date studies. The SRT was concerned that
smalltail sharks may not be as slow-growing as predicted by the Lessa
and Santana (1998) growth model, which may have been biased by the lack
of samples from larger individuals. Smalltail sharks have a late age at
maturity and low fecundity relative to most other small coastal sharks;
however, relative to other Carcharhinid sharks, including species that
support directed fisheries, the smalltail shark matures at a relatively
young age (6 years; Lessa et al., 1999), has a protracted mating season
(Castro 2011b), and produces reasonably large broods, averaging 4 to 10
pups per biennial cycle (Lessa et al., 1999, de Campos Santos et al.,
1999, Castro 2011b). The pups are also reasonably large at birth (i.e.,
>20% of adult size; Lessa et al., 1999, de Campos Santos et al., 1999).
Large size at birth tends to lead to lower natural mortality rates in
shark species by creating a natural predation refuge due to size,
higher foraging competence due to better developed sensory systems, and
higher innate energy reserves (Branstetter 1990, Hoenig and Gruber
1990, Cort[eacute]s 2000). While some existing models and studies, such
as those by Santana et al. (2020), suggest a low intrinsic population
growth rate, low survival rates, and a minimal capacity for recovery
for smalltail sharks relative to other small coastal sharks, these
conclusions are uncertain due to shortcomings in the underlying data
and are contradicted by other studies (Cortes 2002, Cortes 2016, Farmer
2025).
Diversity
There is limited available data to inform an assessment of
smalltail shark genetic diversity. There has been only one
geographically-limited and potentially biased study analyzing the
genetic variability of the smalltail shark; no conclusive signs of
increased or reduced genetic variability were reported (Tavares et al.,
2013). It is reasonable to assume that significant reduction in
abundance would reduce the species' phenotypic and genetic diversity.
However, there is insufficient information to assess whether and to
what degree this reduction has occurred and is contributing to the
species' extinction risk. Further, information related to smalltail
shark life history is outdated (1980s-1990s), and it is unclear if any
changes have occurred over time. Limited genetic and life history
information precludes any evaluation of the population structure or
diversity factor as neither contemporary nor historical baseline
studies needed for comparisons across time are available.
There is no available evidence that there are geographically
distinct or spatially separated populations of this species. Feitosa et
al. (2020a) showed there is suitable habitat throughout the range of
the smalltail shark. Additionally, there is no information on
dispersal, seasonal movement, or migration patterns that would indicate
gene flow could be restricted. Ecological changes directly related to
smalltail shark habitat are largely unknown, and there is no indication
that the potential natural processes that cause ecological variation
have been significantly altered.
Since juvenile smalltail sharks are reported to be caught in higher
numbers than other age classes (Batista and Silva 1995; Santana et al.
2020), it is possible that this removal could lead to alterations in
life history traits over time. Overharvesting of juveniles can lead to
a shift towards earlier maturation, smaller size, and increased
fecundity (Rutter 1903; Kuparinen and Festa-Bianchet 2017). However,
juvenile-dominated catch was documented in the 1980s even when
smalltail sharks were considered to be in higher abundance, and life
history characteristics documented at the time did not appear to
reflect potential changes in growth or reproduction.
Given the above information, the SRT concluded the species does not
appear to be at risk of extinction because of alterations to the
natural processes of dispersal, migration, and gene flow. Some SRT
members (two of six) concluded that the demographic factor of diversity
presented a moderate risk, in part due to the potential changes over
time associated with continued fishing on specific age groups and the
lack of genetic information for this species. The majority of the SRT
(four of six) concluded that diversity was unlikely to significantly
contribute to the species extinction risk (low risk). The SRT noted low
genetic diversity may pose a future risk in combination with low
abundance and continued overexploitation. However, at this time, they
concluded that the evidence is not substantial enough to suggest that
significant changes in or loss of
[[Page 47203]]
phenotypic or genetic traits are altering genetic diversity to the
extent that it is significantly contributing to the species' long-term
extinction risk.
We conclude that an assessment of the smalltail shark's genetic
diversity and population structure is severely limited by a lack of
robust, contemporary data. There is no conclusive evidence of
significant genetic loss; the few available studies include an
inconclusive genetic analysis (i.e., Tavares et al., 2013; see
Population Structure and Genetics, above) and a demographic study
relying on outdated data. It is therefore unclear if reduced genetic
variation is contributing to risk of extinction for the species. We
find that the best scientific information available supports a
conclusion of low risk for diversity and population structure. However,
the lack of a genetic baseline and the potential for fishing pressure
to alter life history traits over time contribute to a high degree of
uncertainty in this conclusion.
Spatial Structure and Connectivity
Smalltail sharks occupy coastal waters out to the continental shelf
edge from eastern Brazil into the northern GOA. Based on species
distribution modeling by Feitosa et al. (2020b), there appears to be
large amounts of suitable habitat available for smalltail sharks
throughout their range. The smalltail shark has a generalist diet
(Lessa and Almeida 1997). Given their generalist nature and habitat
plasticity, the SRT did not identify obvious disruptions in spatial
structure or connectivity, such as geographic range contraction or
isolation, for the species.
As noted above, there is no evidence indicating geographically
distinct or spatially separated populations of this species; however,
the available genetic data are limited. Some reports have suggested the
species may be extirpated from the southern extent of its range, but
there is no indication that the species' distribution throughout its
range has been fragmented or significant gaps in its habitat have been
created. There is minimal available information on connectivity
throughout its range, and natural rates of dispersal are unknown.
In conclusion, although some studies suggest the range of smalltail
sharks has contracted over time, reports suggest that it remains
relatively common along the northern coast of South America. While
there are reports that fishing pressure may be depleting smalltail
shark populations in nearshore shallow water habitats, the species
demonstrates a capacity to utilize a variety of habitats (Feitosa et
al., 2020b). Smalltail sharks do not appear to be limited by dispersal
or a lack of habitat patches, including nursery habitats (Feitosa et
al., 2020a). Habitat degradation from coastal development is not
considered a primary threat. Although information on habitat
destruction and population connectivity is limited, the species'
apparent adaptability and broad range suggest that habitat-related
threats are not currently a primary risk to its overall survival, even
as the core population in northern Brazil faces heightened fishing
mortality. Thus, based on the best available information, the SRT
concluded, and we agree, that spatial structure and connectivity
throughout the species' range poses a low extinction risk to the
smalltail shark in the foreseeable future.
Threats Assessment
As noted previously, section 4(a)(1) of the ESA and NMFS'
implementing regulations (50 CFR 424.11(c)) state that we must
determine whether a species is endangered or threatened because of any
one or a combination of the following factors: (A) the present or
threatened destruction, modification, or curtailment of its habitat or
range; (B) overutilization for commercial, recreational, scientific, or
educational purposes; (C) disease or predation; (D) inadequacy of
existing regulatory mechanisms; or (E) other natural or manmade factors
affecting its continued existence. The SRT summarized information
regarding each of these threats. Similar to the demographics risk
analysis, the SRT members were provided a template and asked to rank
the significance of each threat in terms of its contribution to the
smalltail shark risk of extinction. Risks for each threat were ranked
on a scale of 1 (low risk) to 3 (high risk). More details about the
definitions of the rankings and process followed by the SRT can be
found in the status review report (Heublein et al., 2025). We conclude
the SRT's findings with respect to the ESA section 4(a)(1) listing
factors are well-considered and based on the best available scientific
information, and we concur with their assessment.
Factor A was considered a low threat given the lack of clear
impacts from human activities on the core habitats of smalltail shark
and the lack of direct evidence of health impacts from contaminants on
the species. The BNC is an important region for smalltail sharks, and
Feitosa et al. (2020b) predicted that this area has the highest
occurrence probability throughout the species' range. However, there
are no systematic surveys to assess habitat associations, and relevant
data are almost exclusively fishery-dependent or based on very small
spatial scales. Coastal development and anthropogenic activity may
alter the availability and quality of nearshore habitat; however, there
is no direct evidence that these actions are significantly contributing
to extinction risk of the smalltail shark.
Factor C was considered a low threat due to lack of evidence
suggesting disease or predation were affecting the status of the
species. Factor E was also considered a low threat because there was
limited information regarding how warming seas or increased extreme
weather events would affect smalltail shark. Warming seas may cause
significant habitat loss for the smalltail shark, particularly at the
extreme fringe of their range in the northern Gulf of America (Diaz-
Carballido et al. 2022). However, the species may find thermal refuge
in deeper waters or experience minimal habitat reductions in their core
Brazilian range (O'Brien et al. 2024), where they are also less likely
to suffer from climate-driven changes in prey availability due to their
opportunistic diet (Cort[eacute]s 1999; Gadig 2001; Castro 2011b). The
SRT noted that these conclusions are highly uncertain because there are
no direct studies on the species' climatic variability and the current
modeling reflects broader environmental drivers rather than specific
biological responses. Factors B and D (overutilization for commercial,
recreational, scientific, or educational purposes and inadequacy of
existing regulatory mechanisms) were determined to have potential
impacts on the overall extinction risk of the species. These threats
are discussed in detail below.
Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
Fisheries in U.S. Waters
Time series of landings data are largely absent with the exception
of historical landings records in U.S. waters where catch of smalltail
sharks has been prohibited since 1999 (64 FR 29090, May 28, 1999). No
changes in catch rates or abundance could be detected from the limited
landings data available prior to the harvest prohibition, and there is
no indication that overutilization is a threat to the smalltail shark
in U.S. waters.
Foreign Fisheries
Southern GOA
Fishermen anecdotally report that the species was historically much
more abundant in the southern GOA (Bravo-Zavala et al., 2022), but
recent studies
[[Page 47204]]
have found that they now comprise only a small percentage (0.2-3
percent) of total shark catch in gillnet and longline fisheries in the
Yucat[aacute]n region (Castillo-G[eacute]niz et al., 1999;
P[eacute]rez-Jim[eacute]nez and Mendez-Loeza 2015; P[eacute]rez-
Jim[eacute]nez et al., 2020). Bravo-Zavala et al. (2022) used limited
abundance information to determine that smalltail sharks had low to
moderate cumulative vulnerability to current gillnet and longline
fisheries in the southern GOA. Yet, Bravo-Zavala et al. (2022) also
noted that the species had the lowest rebound potential score among the
small sharks considered in their study, partly due to decreases in
distribution and abundance compared with past decades.
Honduras
Anecdotal reports suggest that the majority of shark species taken
as bycatch in Honduran fisheries are in the family Carcharhinidae,
which includes the smalltail shark (K. Alvarado, Honduras General
Directorate of Fisheries and Aquaculture, personal communication, July
25, 2023); however, species-specific information is lacking. Rojas et
al. (2000) reported that smalltail sharks represented one percent of
commercial fisheries catch in Honduran waters in the 1990s. Directed
fishing and exploitation of shark species has been prohibited in the
maritime territorial waters of Honduras since 2011.
Venezuela
Smalltail sharks are more common in commercial landings along the
northern coast of South America than in Central America. Marquez et al.
(2019) documented that smalltail sharks comprised 3.1 percent of the
elasmobranch catch in the Sucre State (Venezuela) artisanal gillnet and
longline fisheries from 2016 to 2017. Arocha et al. (2002) reported
smalltail sharks made up 8.4 percent of the catch on tuna and swordfish
vessels off Venezuela from 1994 to 2000, but length measurements and
location data suggest possible species misidentification. In a fishery-
independent study conducted in the Gulf of Venezuela during the mid-
2000s, smalltail sharks comprised 2 percent of sharks collected
(Tavares and S[aacute]nchez 2012). The SRT was unable to locate any
analyses regarding the sustainability of Venezuelan landings of
smalltail shark.
Trinidad and Tobago
In Trinidad and Tobago, there is no quantitative data on abundance,
but the limited available information suggests that smalltail sharks
are the most commonly caught shark species (Shing 2006). Shing (2006)
reported that Walker in his 1992 Trinidad and Tobago shark stock
assessment had conducted a preliminary assessment of smalltail shark
abundance and ``concluded that it was not yet at the stage of maximum
exploitation.'' Castro (2011) states: ``It is the most abundant shallow
water shark around Trinidad, where I have seen hundreds taken in a
single bottom gillnet.'' The SRT found it concerning that the gillnet
fisheries in Trinidad and Tobago seem to disproportionately capture
juveniles and gravid females, which can have severe repercussions on
the productivity and resilience of the population (Santana et al.,
2020).
Guyana, Suriname, and French Guiana
Smalltail sharks are regularly harvested in Guyanese fisheries.
Smalltail sharks made up nearly 45 percent of the catch across all
species collected during a study conducted between 1968 and 1970
targeting sharks from Venezuela to French Guiana, and most of the
smalltail sharks were caught handlining off Guyana (Kleijn 1974). The
limited information available suggests smalltail sharks were relatively
common in the coastal waters of Guyana, Suriname, and French Guiana
from 1968 to 1970 (Kleijn 1974). Since this study, limited shark
research has been conducted in this region, but Kolmann et al. (2017)
used DNA barcoding in Guyanese fish markets to determine the smalltail
shark was the second most abundant shark species present (17.4 percent
of all sharks sampled across six markets).
Brazil
The majority of information on smalltail sharks in commercial and
artisanal fisheries comes from Brazil and is described in detail in the
Global and Regional Abundance Estimates and Trends section above. Due
to differences in study design and data limitations, the SRT was unable
to quantitatively estimate declines in smalltail shark abundance in the
BNC or other regions. However, several disparate sources suggest that
fishing pressure has significantly reduced smalltail shark abundance
over the last few decades (e.g., CPUE declines in fisheries, lower
relative abundance in fish markets, age-growth-based demographic
models, and anecdotal accounts). Lessa et al. (2018), citing Stride et
al. (1992) and Morais (2004), reported an 85 percent decline in
smalltail shark catch rates from the 1990s and 2000s from trawl fishery
monitoring; however, the SRT noted inconsistencies in the way this
dataset was described and was not able to acquire the primary source
data to verify the reported trend. Gadig (2001) reported that smalltail
sharks are uncommon on the south coasts of S[atilde]o Paulo but had
been abundant in the 1960s. In a study of the artisanal gillnet fishery
in Maranh[atilde]o, Santana et al. (2020) determined smalltail sharks
were already overharvested in the 1980s. Interviews conducted by
Martins et al. (2018) with experienced artisanal gillnet and longline
fishers in the BNC indicate that smalltail sharks were once easily
caught during the 1980s and 1990s, but are now scarce and found only in
deeper offshore waters. The artisanal gillnet fishery targeting
weakfish and mackerel fishing fleets have increased in size over the
past several decades and are using longer gillnets (three-fold
increase) (Mour[atilde]o et al., 2014; Feitosa et al., 2020b).
Smalltail sharks make up a major component of the bycatch within these
fisheries, and the potential for bycatch has increased through time due
to increasing fishing effort, including increased soak times to offset
declines in target species (Mour[atilde]o et al., 2014; Feitosa et al.,
2020b), which may, in turn, increase bycatch mortality rates. In the
early 2000s, smalltail sharks were the most common (46.7 percent; n=57
of 122) shark examined in BNC fish markets (da Silva Rodrigues-Filho et
al., 2009); however, studies conducted in the BNC from 2014 to 2018
reported that smalltail sharks had dropped to the third most abundant
shark species, representing between 5.5 and 13.1 percent of the total
specimens examined (Feitosa et al., 2018; da Silva Ferrette et al.,
2019; Martins et al., 2021). Although percent presence of smalltail
sharks declined between these studies, the studies are not directly
comparable due to confounding differences in study design and the
enactment of harvest prohibitions by Brazil in 2014.
Several factors could influence commercial fisheries in Brazil and
landings and sale of smalltail sharks over time (e.g., gear, target
species, regulations). However, the disparate sources of available
information consistently suggest a steep decline in the abundance of
smalltail sharks in Brazil. Overfishing in the BNC has likely continued
to deplete the smalltail shark population, as fishing effort is
reported to have increased in spite of declining catch rates (Feitosa
et al., 2019). Similar to Trinidad and Tobago, the SRT was concerned
that BNC gillnet fisheries seem to disproportionately capture juveniles
and gravid females.
The well-documented presence of smalltail shark product in markets
(Feitosa et al., 2018; da Silva Ferrette et al., 2019; Martins et al.,
2021) suggests illegal, unreported, and unregulated
[[Page 47205]]
(IUU) fishing could be a substantial contributor to the overutilization
of the species; however, the level of IUU fishing is unknown, and there
are no available studies assessing the impacts of IUU fishing on the
smalltail shark. It is likely that illegal harvest and trade of
smalltail shark fins is occurring and will continue to occur into the
foreseeable future. Recent information from Brazil indicates the
species is still retained and brought to local markets or shipped
overseas (Feitosa et al., 2018; da Silva Ferrette et al., 2019; Martins
et al., 2021). Globally, demand for shark fins appears to be
decreasing; however, demand for shark meat appears to be increasing
(Dent and Clarke 2015). Recent studies have found smalltail shark fins
being sold in Hong Kong markets (Carde[ntilde]osa et al., 2018). It is
unclear if these fins are sourced from illegal shark fishing or
international trade operations. Despite the recent listing of
Carcharhinid sharks (including smalltail sharks) in Convention on
International Trade in Endangered Species of Wild Fauna and Flora
(CITES) Appendix II, the efficacy of this listing may be insignificant
if compliance and reporting are poor. Further, CITES measures apply
only to international trade and do not address compliance with national
fishing restrictions and domestic trade. Overall, given the high
likelihood of underreported harvest data and inconsistencies with data
collection, IUU fishing of smalltail sharks, and the evidence of
significant declines of smalltail sharks in the core of their range,
the SRT concluded that smalltail shark populations are likely subject
to high exploitation rates throughout the majority of their range, with
overutilization significantly contributing to the species' risk of
extinction in the foreseeable future.
Summary
All SRT members agreed that fishing, including IUU fishing, is the
greatest threat to smalltail sharks. Harvest of the species has
primarily involved targeted and incidental catch in commercial and
artisanal fisheries off the northern coast of South America. The best
available information suggests a significant decline in smalltail shark
populations within the core of the species' range along the BNC since
the 1980s (Santana et al., 2020), and this conclusion is supported by a
number of regional experts (Pollom et al., 2020). Interviews by Martins
et al. (2018) suggest that fishing practices in the BNC have changed
little over the past 4 decades, but effort has increased (Feitosa et
al., 2019) and harvest and sale have continued regardless of
regulations (Feitosa et al., 2018; da Silva Ferrette et al., 2019). It
is impossible to characterize with certainty the rate or extent to
which the species has declined due to inconsistencies in sampling
methods and data types between studies. The available fishing data from
non-core areas to the north and south of BNC is insufficient to draw
any conclusions about abundance trends in these areas. Based on the
uncertainty in the rates of decline and the limited data from regions
outside BNC, the majority of the SRT ranked commercial and artisanal
fishing as a moderate threat to the extinction of the smalltail shark.
However, one SRT member gave this a high threat ranking (the only high
ranking awarded by any SRT member to any threat or demographic risk)
due to the scale and intensity of fishing pressure in northern South
America.
In conclusion, we find that overutilization, primarily from
artisanal and commercial fishing, is the most significant threat to the
smalltail shark, particularly within its core population area off
northern Brazil. While the species is not typically a target for
commercial fisheries, it is a frequent component of bycatch in gillnet,
longline, and trawl fisheries, where a disproportionate number of
juveniles and gravid females are captured. The intensity and
unregulated nature of this fishing pressure have likely driven
significant population declines, with anecdotal reports and some
empirical data suggesting a substantial reduction in catch and
distribution over time, including a reported 85 percent decline in
trawl CPUE in northern Brazil from the 1990s to the 2000s. However,
data limitations and inconsistent methodologies make it difficult to
extrapolate a single estimate of population decline across the species'
range and to present day. In addition to legal harvests, illegal
fishing and poaching for the fin trade are documented (Feitosa et al.,
2018; da Silva Ferrette et al., 2019; Carde[ntilde]osa et al., 2020;
Martins et al., 2021; Liu et al., 2021). This illegal activity,
alongside the general lack of effective regulation and poor compliance,
further exacerbates the threat to the species and complicates
management efforts.
Inadequacy of Existing Regulatory Mechanisms
Smalltail shark fins and meat have high commercial value, and
inadequate regulatory mechanisms can leave the species vulnerable to
overharvest. All countries within the species' range have measures in
place to prevent shark finning, and 10 of 31 countries either prohibit
all shark harvest or have specific regulations on the harvest of
smalltail sharks. However, the success of these regulations, including
their enforcement, varies. Below is a summary of regulatory measures
that currently apply to the species throughout its range and an
analysis of whether they are inadequate to protect the species from
identified threats.
U.S. Domestic Regulatory Mechanisms
In U.S. waters, there is no sign of decline in smalltail shark
landings prior to harvest prohibitions, and there are no contemporary
landings or illegal harvest reports indicating that compliance and
enforcement are inadequate. There are a variety of regulatory measures
in place to protect the species, described below.
Magnuson-Stevens Fishery Conservation and Management Act (MSA)
The MSA is the primary law governing marine fisheries management in
U.S. Federal waters, which extend from the seaward boundary of each of
the coastal states out to the outer boundary of the exclusive economic
zone (EEZ), generally 200 nautical miles offshore. Key purposes of the
MSA are to ``take immediate action to conserve and manage the fishery
resources found off the coasts of the United States'' and ``promote
domestic commercial and recreational fishing under sound conservation
and management principles.'' 16 U.S.C. 1801(b)(1)(3). The MSA directs
the Secretary to prepare fishery management plans (FMPs) with respect
to highly migratory species (HMS), including sharks, in the U.S. EEZ of
the Atlantic Ocean, GOA (MSA uses ``Gulf of Mexico'' to describe the
area that has been renamed as Gulf of America), and Caribbean Sea (16
U.S.C. 1852(a)(3) and 16 U.S.C. 1854(f)(3)). The Atlantic HMS
Management Division within NMFS develops regulations for Atlantic HMS
fisheries in Federal waters (domestic) and, for U.S. citizens and
vessels, on the high seas (international). Smalltail sharks are managed
in the prohibited species complex. Sharks in this complex cannot be
retained or possessed. Smalltail sharks were originally part of the
small coastal species management unit starting in 1993 (58 FR 21931,
April 26, 1993); however, they were added to the prohibited shark
complex as part of the 1999 FMP for Atlantic Tunas, Swordfish, and
Sharks (64 FR 29090, May 28, 1999).
Individual states establish regulations for sharks in state waters.
However, as a condition of their HMS permit, federally permitted shark
fishers are
[[Page 47206]]
required to follow Federal regulations in all waters, including state
waters, unless the state has more restrictive regulations. The Atlantic
States Marine Fisheries Commission implemented an interstate coastal
shark FMP in 2010. This interstate FMP coordinates shark management
measures among all states along the Atlantic coast (Florida to Maine).
States in the GOA (Alabama to Texas) and U.S. territories in the
Caribbean do not have the same coordination. However, smalltail sharks
have been prohibited in commercial fisheries in all U.S. states and
territories since 2014 or earlier (Heublein et al., 2025, appendix 1).
Shark Finning Prohibition Act of 2000
The Shark Finning Prohibition Act was enacted in December 2000 and
implemented by final rule on February 11, 2002 (67 FR 6194). Section 9
of the Shark Finning Prohibition Act defines finning as the practice of
taking a shark, removing the fin or fins from a shark, and returning
the remainder of the shark to the sea. Section 3 of the Shark Finning
Prohibition Act amended the MSA to prohibit any person under U.S.
jurisdiction from: (i) engaging in the finning of sharks; (ii)
possessing shark fins aboard a fishing vessel without the corresponding
carcass; and (iii) landing shark fins without the corresponding
carcass. Section 3 of the Shark Finning Prohibition Act also contains a
rebuttable presumption that any shark fins landed from a fishing vessel
or found on board a fishing vessel were taken, held, or landed in
violation (of the act) if the total weight of shark fins landed or
found on board exceeds 5 percent of the total weight of shark carcasses
landed or found on board. The Shark Finning Prohibition Act also
requires NMFS to provide Congress with an annual report describing our
efforts to implement the law. The 2018 Shark Finning Report (NMFS 2018)
indicated the mean value of shark fin imports dropped from $12,000 to
$5,000 per metric ton from 2016 to 2017 before reaching $0 when all
imports ceased in 2019 (NMFS 2023). The same reports showed that the
mean value of exports decreased from $71,000 per metric ton in 2016
(NMFS 2018) to $5,515 per metric ton in 2022 (NMFS 2023). U.S.
participation in the fin trade is decreasing, although this could be
driven by reduced demand for shark fins worldwide (Dent and Clarke
2015).
Shark Conservation Act of 2010
The Shark Conservation Act was signed into law on January 4, 2011,
and amended the High Seas Driftnet Fishing Moratorium Protection Act
and the MSA to improve existing domestic and international shark
conservation measures. To address concerns over the practice of shark
finning, the Shark Conservation Act, among other things, prohibits any
person from removing shark fins at sea (with a limited exception for
smooth dogfish) or possessing, transferring, or landing shark fins
unless they are naturally attached to the corresponding carcass.
Shark Fin Sales Elimination Act of 2023
The Shark Fin Sales Elimination Act became effective on December
23, 2022. The law prohibits the possession, transport, and sale of
shark fins with limited, narrow exceptions. In combination with the
Shark Finning Prohibition Act of 2000 and the Shark Conservation Act of
2010, this law allows fishers to transport, land, sell, and export
whole sharks with fins naturally attached; however, they may not land,
possess, sell, or export detached fins.
Summary of Findings: Inadequacy of Existing U.S. Domestic Regulatory
Measures
Landing records of smalltail sharks in U.S. waters were rare prior
to Federal harvest prohibitions. Smalltail shark landings were reported
only in 9 years between 1984 (NMFS' earliest landing record) and 2000
(the earliest implementation of Federal prohibitions). Adoption of the
prohibited shark complex from the 1999 FMP for Atlantic Tunas,
Swordfish, and Sharks by all U.S. states and territories (2014 or
earlier) has reduced the harvest of smalltail sharks to likely rare
incidents of misidentification. Smalltail sharks have only been
reported in one landings record since the adoption of harvest
prohibitions in all U.S. waters (NMFS 2018). Notably, this recreational
landings record could have been a case of misidentification or
unawareness of regulations.
Implementation of the Shark Finning Prohibition Act, the Shark
Conservation Act, and the Shark Fin Sales Elimination Act have resulted
in declines in U.S. exports of shark fins. Additionally, 14 U.S. states
and 3 U.S. territories have enacted legislation controlling shark
finning by banning the possession and sale of shark fins (Heublein et
al., 2025, appendix 1). These state laws have reduced U.S. landings of
sharks and therefore U.S. trade and consumption of shark fins. However,
it is important to note that the United States has traditionally played
a relatively minimal role in the global shark fin trade (0.3 and 0.4
percent of global imports and exports in U.S. dollars according to
Ferretti et al. (2020)). Measures prohibiting the possession and sale
of shark fins may provide some additional conservation benefits to
sharks, including the smalltail shark, by discouraging the landing of
any sharks.
International Regulatory Mechanisms
Regulations in Brazil
Brazil is the only country outside of the United States and its
territories with regulations specifically addressing smalltail sharks.
Smalltail sharks were listed as critically endangered on the Brazilian
National Red List in 2014 (Ordinance 445/2014) and this designation was
reaffirmed in the 2023 update (Ordinance 354/2023). The listing
prohibits the capture, transport, storage, processing, and
commercialization of the species. Monitoring and enforcement of these
regulations, however, is limited and implementation status is
considered uncertain (Begossi et al., 2017; Pollom et al., 2020).
Available reports suggest that regulations to protect smalltail sharks
from harvest in Brazil are not effectively enforced, as the species
continues to be identified in Brazilian fish market samples. Feitosa et
al. (2018) evaluated samples collected between 2014 and 2016 from the
major BNC fishing ports of Bel[eacute]m (n=26), Bragan[ccedil]a (n=55),
Vigia (n=13), Carutapera (n=14), Raposa (n=53), Tutoia (n=219) and
broadly across Amapa state (n=48) in 2007 and found that smalltail
shark fins comprised 9.8 percent of all identified samples. Similarly,
da Silva Ferrette et al. (2019) evaluated the species composition of
three large seizures of shark fins conducted by Brazilian law
enforcement in Bel[eacute]m, Natal, and S[atilde]o Paulo and found that
smalltail shark fins comprised 13.1 percent of all identified samples
(n=98/747).
United Nations Convention on the Law of the Sea (UNCLOS)
The UNCLOS defines the rights and responsibilities of signatory
nations with respect to their use of the world's oceans, establishing
guidelines for businesses, the environment, and the management of
marine natural resources. The importance of collaborative management
for highly migratory species is addressed in Article 64, which states:
``The coastal State and other States whose nationals fish in the region
for the highly migratory species listed in Annex I shall cooperate
directly or through appropriate international organizations with a view
to ensuring conservation and promoting
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the objective of optimum utilization of such species throughout the
region, both within and beyond the exclusive economic zone.''
Carcharhinid sharks (including smalltail sharks) are listed in Annex I,
Highly Migratory Species, of UNCLOS and, therefore, benefit from the
cooperation required under Article 64. These provisions require party
nations to regulate activities of vessels flying their flag and give
them the right to monitor and inspect vessels of other nation parties
to ensure compliance with internationally agreed fishing regulations,
including regulations established by regional fishery management
organizations (RFMOs).
Convention on International Trade in Endangered Species of Wild Fauna
and Flora (CITES)
CITES is an international convention that aims to ensure that
international trade in animals and plants does not threaten their
survival, and Carcharhinid sharks (including smalltail sharks) were
included in Appendix II of CITES on November 25, 2023. Appendix II
includes species not necessarily threatened with extinction, but whose
trade must be controlled to ensure utilization is compatible with their
survival. Thus, international trade in smalltail sharks is allowed with
an export permit, re-export certificate, or introduction from the sea
(IFS) certificate granted by the proper management authority. These
permits or certificates may be granted if the trade is found to be non-
detrimental to the species' survival in the wild and the specimen was
found to have been legally acquired. An IFS certificate applies when a
specimen is taken on the high seas (not under any state's jurisdiction)
and landed in a state. An analysis of trade data and fin samples from a
Hong Kong market led Carde[ntilde]osa et al. (2018) to conclude that
compliance with reporting of trade of CITES-listed shark species was
low in 2015 through 2016. However, due to the recency of the species'
inclusion in Appendix II, compliance with CITES reporting and
permitting requirements for this species is unknown.
International Shark Fishing and Finning Regulations
Finning bans and regulations have been implemented by several
countries and RFMOs (Heublein et al., 2025, appendix 1). These finning
bans and regulations range from requiring fins to remain attached to
the body to allowing fishers to remove shark fins if the weight of the
fins does not exceed 5 percent of the total weight of shark carcasses
landed or found onboard. This latter measure limits shark finning while
allowing processing flexibility to the fishing industry (Shiffman and
Hammerschlag 2016). All of the relevant RFMOs prohibit the retention of
fins onboard that weigh more than 5 percent of the weight of sharks to
curb the practice of shark finning. Under the fin-to-carcass ratio
measure, landing sharks that do not have fins attached to the body
makes it difficult to match fins to a carcass (Lack and Sant 2009).
This can allow for switching the fins of species fishers can legally
land the carcasses of for the fins of prohibited but more valuable
species, a practice called ``high grading'' (Shiffman and Hammerschlag
2016). Controls on finning also lack the capacity to provide
differential protection to those shark species most at risk from
overfishing and have no impact on the mortality of sharks that are
discarded because their fins have either no or very low market value
(Lack and Sant 2009). Several countries have enacted complete shark
fishing bans (i.e., bans on retention and possession of sharks and
shark products), including Honduras (2010), The Bahamas (2011), the
Cayman Islands (2015), the British Virgin Islands (2015), Bonaire
(2015), Sabah (2015), St. Maarten (2016), and the Dominican Republic
(2017) (Porcher and Darvell 2022). Mexico implemented a seasonal (May
through June) ban on shark fishing in the GOA and Caribbean starting in
2012. International laws and regulations intended to curb finning are
not always effectively enforced by countries and RFMOs (Biery and Pauly
2012). Despite these measures, smalltail shark fins continue to be
found in illicit shark fin stockpiles in Brazil, which are likely bound
for Asian markets (da Silva Ferrette et al., 2019; Carde[ntilde]osa et
al., 2020; Liu et al., 2021).
Summary of Findings: Inadequacy of Existing International Regulatory
Measures
Although international agreements under the authority of UNCLOS,
CITES, and RFMOs play an important role in facilitating cooperation
between participating countries, challenges in identifying vessels,
ports, and authorities and at-sea enforcement limit their efficacy at
controlling overutilization of smalltail shark. The detection of
smalltail shark fins in Hong Kong markets in 2018 and illicit shark fin
stockpiles in Brazil after shark finning was banned throughout most of
the species range (da Silva Ferrette et al., 2019; Carde[ntilde]osa et
al., 2020) suggests continued noncompliance with these international
agreements.
The efficacy of regulations within the EEZ of specific fishing
nations may face similar challenges, and it is difficult to validate
compliance. Smalltail sharks appear to be or have once been common in
multiple South American and Caribbean countries (i.e., Venezuela,
Guyana, and Trinidad and Tobago). However, there are no recent surveys
or monitoring data in these countries to estimate abundance trends.
Thus, we are unable to assess if the regulations in these countries are
adequate to protect the smalltail shark from overfishing.
Although mostly based on disparate and anecdotal data sources, all
available reports indicate the abundance of smalltail sharks in Brazil
(specifically the BNC) is in decline due to both directed harvest and
bycatch. The lack of monitoring data and enforcement along largely
undeveloped coastlines prevents the development of fisheries management
plans that could mitigate the threat of overutilization. The reduced
abundance, continued landings (Feitosa et al., 2018), and finning of
the species (da Silva Ferrette et al., 2019) all suggest that the
harvest and shark finning regulations are inadequately enforced in
Brazil, the core of the species' range. The fisheries statistics
program in Brazil was discontinued in 2011 (Barreto et al., 2017), and
fishing effort has increased with declining catch rates and little
oversight (Santana et al., 2020). These varying lines of evidence all
suggest that existing regulatory mechanisms are inadequate to
effectively address the threat of overutilization.
Ultimately, the SRT was not able to conclusively assess the
adequacy of current regulations and compliance outside of Brazil and
U.S. waters. However, given the available information that is
indicative of poor enforcement in the core range (e.g., declining
trends, recent presence in fish markets, and fin seizures) and the
probable issues with monitoring and enforcement throughout the
Amazonian Coast, five of six SRT members concluded that the threat of
inadequate existing regulatory mechanisms is a moderate risk to the
species.
We agree with the SRT's conclusion that although various countries
within the smalltail shark's range, including Brazil, have established
regulations to manage shark stocks and prevent overfishing, the
implementation and enforcement of these measures are likely inadequate
to address the threat of overutilization, especially in the species'
core habitat. Brazil, for instance, has prohibited the harvest of
smalltail sharks since 2014; however, this regulation appears poorly
enforced, with smalltail sharks and their fins still commonly found in
local markets and
[[Page 47208]]
law enforcement seizures. While some international and national
regulations (e.g., in the United States and Honduras) are deemed
sufficient, their effectiveness across the species' broad and multi-
jurisdictional range is difficult to assess. The lack of monitoring
data and a clear understanding of the full extent of illegal harvest
and poaching prevent the development of a comprehensive management
plan. As a result, the inadequacy of both existing regulations and
their enforcement, particularly in Brazil, remains a significant threat
to the species.
Overall Extinction Risk Assessment
Guided by the results from their demographic risk analysis and
threats assessment, the SRT members used their informed professional
judgment to make an overall extinction risk assessment for the
smalltail shark. Here, we first review the SRT's findings and next
discuss our conclusions regarding the risk of extinction to the
smalltail shark. The SRT used a likelihood point (Forest Ecosystem
Management Assessment Team 1993) method to evaluate the overall risk of
extinction and express uncertainty. Each SRT member distributed 10
likelihood points among the following three extinction risk categories:
Low risk: A species is at low risk of extinction if it is not at
moderate or high level of extinction risk (see moderate risk and high
risk below). A species may be at low risk of extinction if it is not
facing threats that result in declining trends in abundance,
productivity, spatial structure, or diversity. A species at low risk of
extinction is likely to show stable or increasing trends in abundance
and productivity with connected, diverse populations.
Moderate risk: A species is at moderate risk of extinction if it is
on a trajectory that puts it at a high level of extinction risk in the
foreseeable future (see description of high risk below). A species may
be at moderate risk of extinction due to current or projected threats
or declining trends in abundance, productivity, spatial structure, or
diversity.
High risk: A species with a high risk of extinction is at or near a
level of abundance, productivity, spatial distribution/connectivity, or
diversity that places its continued persistence in question. The
demographics of a species at such a high level of risk may be highly
uncertain and strongly influenced by stochastic or depensatory
processes. Similarly, a species may be at high risk of extinction if it
faces clear and present threats (e.g., confinement to a small
geographic area; imminent destruction, modification, or curtailment of
its habitat; or disease epidemic) that are likely to create imminent
and substantial demographic risks.
Based on the demographic factors contributing to risk, the evidence
of significant declines in abundance and overutilization in fisheries,
and inadequacy of current regulations and enforcement to control that
threat, the SRT assigned the majority of likelihood points (53 percent)
to the moderate risk category. Due to uncertainty caused by the lack of
landings data and inconsistent study methodologies, team members placed
many of their likelihood points in the low risk (42 percent) and, to a
much lesser extent, high risk (5 percent) categories. Overall, three of
six (50 percent) SRT members assigned six or more of their likelihood
points to the moderate risk category.
The SRT's primary concerns for smalltail shark were the cumulative
threat of overutilization and the inadequacy of existing regulatory
mechanisms to address it. While there is not currently a targeted
fishery for smalltail sharks, the species has historically comprised a
significant component of retained bycatch in various artisanal
fisheries throughout their core range (Almeida et al., 2011). The
threat of overutilization is exacerbated by the lack of enforcement and
monitoring of fisheries regulations in the core of the range off Brazil
and potentially across the broader northern South America region.
Although smalltail shark life history studies are outdated and
potentially inapplicable for assessing the current population, the
consistent reports of population decline from various sources and the
limited life history information suggest that the species has
relatively low population growth. However, the magnitude of population
decline could not be accurately quantified, it was unclear whether
declines had occurred in several areas within the range, and the growth
potential was higher than most medium-growing shark populations. In
their overall extinction risk assessment, the SRT was divided in their
opinion of whether the species is on a trajectory that would put it at
a high level of extinction risk in the foreseeable future, with three
members assigning half or more of their points to moderate or high risk
and three members assigning half or more of their points to low risk.
The SRT concluded that available information does not demonstrate
that the smalltail shark is currently at or near a level of abundance,
productivity, spatial structure, or diversity that places its
persistence in question. Despite multiple lines of evidence (Gadig
2001; Feitosa et al., 2018; Martins et al., 2018; da Silva Ferrette et
al., 2019; Martins et al., 2021; Bravo-Zavala et al., 2022) suggesting
declines, potentially of greater than 90 percent (Santana et al., 2020)
since the 1980s, smalltail sharks continue to be relatively abundant in
BNC fish markets (da Silva Rodrigues-Filho et al., 2009; Feitosa et
al., 2018; da Silva Ferrette et al., 2019; Coelho et al., 2025). While
there is compelling evidence of localized decreases in smalltail shark
abundance, uncertainty in the current and projected abundance to 2050
was a major reason three of six SRT members assigned at least half of
their points to the low category.
The near even split between low and moderate extinction risk scores
was also driven by the uncertainty regarding the future of smalltail
shark management. The SRT found that regulatory controls for smalltail
shark populations are generally increasing; however, the efficacy of
those controls is questionable. If regulations were adequately
enforced, then the increasing regulations seen in most parts of the
smalltail sharks' range may facilitate an increase in abundance.
However, if direct harvest, including illegal harvest, continues
unabated, there is a chance of smalltail shark abundance declining in
the core range in the foreseeable future. Furthermore, in fisheries
with high bycatch of smalltail sharks, the target species are also
experiencing substantial declines in numbers, which has resulted in
extended soak times for fishing gear (Mor[atilde]u et al., 2014;
Feitosa et al., 2019) and an increase in the likelihood of bycatch
mortality. These trends could result in a higher risk of extinction for
this species.
Overall, after considering the best available scientific and
commercial information, including the uncertainty in that information,
the SRT collectively assessed that the smalltail shark is most likely
at a moderate risk of extinction throughout its range. The SRT
concluded that declining abundance, limited reproductive capacity, and
trends in the threats of overutilization (through commercial,
artisanal, and IUU fishing) and inadequate management and enforcement
put smalltail shark on a trajectory towards a high level of extinction
risk in the foreseeable future. The SRT assigned an average of 5.3
1.6 points to moderate and 4.2 1.8 points to
low risk, reflecting substantial uncertainty whether the species was at
low or moderate risk. The SRT members provided narratives supporting
their overall risk recommendations. A common theme was that the limited
and
[[Page 47209]]
often contradictory life history data and the presence of numerous
sources of bias in existing studies makes a definitive conclusion on
the severity and urgency of the extinction risk impossible. The
narratives provided by SRT members indicate they spread points across
categories to reflect their significant uncertainty about population
status into their risk scoring, but most did not think there was
sufficient information to definitively support a recommendation of
moderate extinction risk.
In making our determination with respect to whether the smalltail
shark warrants listing under the ESA, we considered the SRT's review,
along with the best available scientific and commercial data, in light
of the ESA's standards for making listing determinations. We agree with
the SRT's conclusion that the most prominent threat to smalltail sharks
is overutilization, primarily from unregulated artisanal and commercial
fishing that disproportionately harvests vulnerable juveniles and
gravid females, particularly in the species' range off the BNC. We
agree with the SRT's conclusion that smalltail shark population
abundance has likely declined in the BNC and agree that the magnitude
of this decline is impossible to quantify due to a pervasive lack of
robust scientific data. We find substantial uncertainty and conflicting
information with regards to the abundance of the smalltail shark.
Despite apparent declines in the BNC (Santana et al. 2020), and despite
being a prohibited species in Brazil, the species still commonly
appears in BNC markets (Feitosa et al., 2018; da Silva Ferrette et al.,
2019; Martins et al., 2021) and is commonly caught in all areas of the
BNC (Coelho et al., 2025). Limited data from 1985 to 2000 (Shing 2006)
and from fish markets (Kolmann et al., 2017) indicate the species may
be relatively common in Trinidad and Tobago and Guyana, respectively.
We find there is adequate information to indicate the species has
declined from historical levels and is likely overfished; however,
there is substantial uncertainty in the magnitude of the decline and
the demographic consequences of the decline.
We agree with the SRT's conclusion that the demographic
consequences of overutilization and inadequate regulatory controls for
smalltail shark are uncertain. Smalltail shark are capable of
inhabiting a broad geographic range of suitable habitats (Feitosa et
al., 2020b), including multiple nursery habitats (Feitosa et al.,
2020a), and are opportunistic predators with a generalist diet (Lessa
and Almeida 1997). Demographic plasticity is typically associated with
resilience for species (Bradshaw 1965; Stearns 1976; Warner and Chesson
1985; Taylor et al., 2019). Additionally, despite their potentially low
productivity relative to most small coastal sharks (Santana et al.,
2020), we find that relative to most Carcharhinid sharks, including
several species that support directed fisheries, smalltail sharks
mature at a relatively young age (6 years; Lessa et al., 1999), have a
protracted mating season (Castro 2011b), and produce a relatively large
brood (Lessa et al., 1999; de Campos Santos et al., 1999; Castro
2011b). These traits give them an intrinsic population growth potential
exceeding that for most shark species characterized as having medium-
growing populations (Cortes 2016; Farmer 2025). Given their relatively
rapid reproductive rates and shorter generation times, we expect
smalltail shark populations to be better able to compensate for
individuals removed through harvesting (Myers and Mertz 1998) than most
shark species, particularly in the absence of a directed fishery;
however, empirical data to support this conclusion is lacking.
Conversely, we note that the species appears to have lower reproductive
potential than most small coastal sharks and demographic modeling
suggests a potentially extreme decline (Santana et al., 2020). Overall,
there is no indication that global abundance has declined to the point
that reproductive success of the species has declined or inbreeding has
resulted (Tavares et al., 2013), nor is there evidence of other
depensatory processes associated with small populations. However, we
note that the only genetic study conducted (Tavares et al., 2013) was
small in scale and not specifically designed to evaluate demographic
risk.
We must determine on the basis of the best scientific and
commercial data available whether a species is at risk of extinction,
and we conclude that the available evidence is insufficient to indicate
the smalltail shark is in danger of extinction or likely to become so
within the foreseeable future. The Status Review Report, the narratives
and extinction risk recommendation of the Status Review Team, and the
best scientific information available, as described above, emphasize
the conflicting information and substantial uncertainty surrounding the
status of this species. That uncertainty was a primary factor
considered by the SRT in making a moderate risk recommendation, and we
find that the demographic and threats-based evidence supporting the
SRT's moderate risk recommendation is insufficient to indicate
smalltail sharks are in danger of extinction or likely to become so
within the foreseeable future throughout their range.
Determination of Status Throughout a Significant Portion of Its Range
As noted previously, a species may warrant listing under the ESA if
it is in danger of extinction or likely to become so in the foreseeable
future throughout all or a significant portion of its range. Thus, a
species may be endangered or threatened throughout the entirety of its
range, or a species may be endangered or threatened throughout only a
significant portion of its range. In 2014, NMFS and USFWS finalized a
policy that provided the agencies' interpretation of the phrase
``significant portion of its range.'' (``SPR Policy,'' 79 FR 37578,
July 1, 2014). Certain aspects of the SPR Policy have been invalidated
by courts (e.g., Desert Survivors v. DOI, 336 F. Supp. 3d 1131 (N.D.
Cal. 2018), Center for Biological Diversity (CBD) v. Everson, 435 F.
Supp. 3d 69 (D.D.C. Jan. 28, 2020)). Given our conclusion that
available evidence is insufficient to indicate smalltail sharks are in
danger of extinction or likely to become so within the foreseeable
future throughout the species' range, we evaluated whether there is any
portion of the species' range for which both (1) the species is at a
moderate or high risk in that portion and (2) the portion is
significant. Both criteria must be met to allow for listing the species
based on its status in the SPR.
As discussed in the SPR Policy, theoretically, there are an
infinite number of ways to divide a species' range into portions.
Because the majority of relevant smalltail shark data (e.g., population
trends, fisheries regulations) were collected or summarized at the
jurisdiction level and the primary identified threats to smalltail
sharks (i.e., overutilization, illegal harvest, and inadequate
regulations) are managed at the jurisdiction level, the SRT initially
evaluated portions at the level of jurisdictions. However, the SRT
found a paucity of demographic information or information on threats
for the smalltail shark outside of Brazilian waters. Even in Brazil's
coastal waters, the reported quantitative population trends require
accepting considerable assumptions (see Abundance and Growth Rate and
Productivity in Extinction Risk Results and Conclusions). Brazilian
waters, specifically those of the BNC, are the reported core
distribution of the smalltail shark (Feitosa et al., 2020b;
[[Page 47210]]
Santana et al., 2020), based on their relatively common encounters in
fisheries in that region (Feitosa et al., 2018; da Silva Ferrette et
al., 2019; Coelho et al., 2025). The apparent relative abundance of
smalltail sharks within the BNC suggests this region may serve as the
source population for smalltail sharks on the periphery of their range.
The SRT assessed extinction risk in Brazil and assigned 55 percent of
overall extinction risk points to the moderate risk category and 38
percent to the low risk category. On average, the SRT assigned 5.5
1.4 points to moderate risk and 3.8 1.3
points to low risk out of 10 possible points, with their point spread
reflecting uncertainty in the underlying data used to determine
extinction risk. The majority of scientific studies involving smalltail
shark considered in the SRT's range-wide recommendation originated in
Brazil, and specifically the BNC; as such, the SRT's scoring was nearly
identical with their range-wide scoring.
Based on the best available scientific and commercial information,
we agree with the SRT that the BNC likely represents the historical
core population for smalltail sharks. We agree with the SRT's
conclusion that although smalltail shark population abundance has
likely declined in the BNC, the magnitude of this decline is impossible
to quantify due to a pervasive lack of robust scientific data. We note
that despite possibly extreme declines (Santana et al., 2020) and
despite being a prohibited species in Brazil not directly targeted by
any fishery, the species still commonly appears in BNC markets and
catches (Feitosa et al., 2018; da Silva Ferrette et al., 2019; Martins
et al., 2021; Coelho et al., 2025). The common appearance of smalltail
sharks in BNC markets suggests inadequate enforcement but also somewhat
contradicts demographic projections predicting population collapse in
the region (Santana et al., 2020). The smalltail shark exhibits a broad
distribution with a generalist diet and multiple nursery habitats and
possesses key life-history traits--including early maturity, large
brood size, and medium population growth relative to most shark species
(Cort[eacute]s 2016; Farmer 2025)--that confer demographic plasticity
and resilience. We conclude that there is reasonable evidence to
suggest that smalltail sharks are likely overharvested off Brazil,
despite the lack of a directed fishery. However, we find that the
evidence supporting the SRT's moderate risk recommendation for the
Brazil portion is insufficient to overcome the substantial
contradictions and uncertainty noted above. We find that, similar to
the range-wide extinction risk assessment, which was primarily informed
by data from studies conducted in the BNC, uncertainty was a primary
factor considered by the SRT in making a moderate risk recommendation
for the Brazil portion of the range. We find that the demographic and
threats-based evidence supporting the SRT's moderate risk
recommendation is insufficient to support a listing recommendation
under the ESA. We conclude that the available evidence is insufficient
to indicate smalltail sharks are in danger of extinction or likely to
become so within the foreseeable future in the Brazil portion of the
range.
The SRT evaluated 15 total jurisdictions in the range of smalltail
shark for extinction risk (table 4 in Heublein et al., 2025), including
Brazil, and assigned the majority of points to moderate risk for all
jurisdictions other than the United States, which was scored as mostly
low risk. The SRT noted that for jurisdictions other than Brazil in
northern South America (e.g., Guyana, Suriname, French Guiana, Trinidad
and Tobago), demographic data are extremely limited to inform a risk
determination. No jurisdiction received more moderate risk points from
the SRT than Brazil. Mexico received 53 percent moderate risk points,
and 10 other jurisdictions received 50 percent. Most jurisdictions
received few (3 to 7 percent) high risk points. Nicaragua received 50
percent moderate risk points but also received 12 percent high risk
points. The high risk points assigned to Nicaragua were assigned by one
SRT member due to concerns about the lack of data and reflected their
uncertainty in assigning risk points. All jurisdictional portions
evaluated were consistent with the range-wide recommendation of
moderate risk with the exception of U.S. waters, which received a
majority (58 percent) of low risk points. The SRT considered combining
portions; however, given that no portions were found to have elevated
risk of extinction relative to the species' risk throughout its range,
the SRT concluded that any combination of the jurisdiction-level
portions would have the same or lower extinction risk than the
jurisdiction-level portions from which it was comprised. Because no
portions exceeded the SRT's moderate risk recommendation for the range-
wide listing, the SRT did not evaluate any portions for significance.
We have considered the SRT's analysis and partially agree with
their conclusions regarding the risk of extinction for smalltail shark
in different portions of the range. We concur that U.S. waters, with
extremely limited historical occurrence of the species and considerable
regulations affording effective protections, are low risk to the
species. We find no evidence of decline off Trinidad and Tobago (Shing
2006) and Guyana (Kolmann et al., 2017). We conclude that smalltail
sharks within these portions are facing low risk of extinction.
For Mexico, a study by Bravo-Zavala et al. (2022) suggested low to
moderate cumulative vulnerability to current gillnet and longline
fisheries, with low documented catch rates supporting the low
vulnerability designation. Bravo-Zavala et al. (2022) note that fishers
indicated the species was very abundant in Campeche before the 1990s
whereas it only accounted for 2% of the total shark catches in the area
in the 1990s (Castillo-G[eacute]niz et al., 1998). Bravo-Zavala et al.
(2022) suggest that cumulative susceptibility and cumulative
vulnerability for the species was likely higher before the 1990s than
after. Although this finding suggests a decrease in abundance and/or
distribution for smalltail shark populations in the Campeche Bank area,
insufficient information is available to determine the magnitude or
significance of this decline for this small coastal shark species with
relatively high population growth potential. We conclude there is
insufficient information to assign an overall risk recommendation to
the Mexico portion. Similarly, we find no information regarding
demographic factors or trends for smalltail shark in Belize, Columbia,
Costa Rica, French Guiana, Guatemala, Honduras, Nicaragua, Panama,
Suriname, or Venezuela. We conclude that the available evidence is
insufficient to indicate smalltail sharks are in danger of extinction
or likely to become so within the foreseeable future in these portions
of the range.
Distinct Population Segments Analysis
Under the ESA, a listing determination may address a ``species,''
which is defined to also include subspecies, and, for any vertebrate
species, any DPS that interbreeds when mature (16 U.S.C. 1532(16)). A
joint policy issued by the USFWS and NMFS provides criteria for
determining DPSs (``DPS Policy,'' 61 FR 4722, February 7, 1996). The
joint DPS Policy identifies two elements that must be considered when
identifying a DPS: (1) the discreteness of the population segment in
relation to the remainder of the taxon to which it belongs and (2) the
significance of the population segment to the remainder of the taxon to
which
[[Page 47211]]
it belongs. A population segment may be considered discrete if it is
markedly separate from other populations of the same taxon as a
consequence of physical, physiological, ecological, or behavioral
factors, or if it is delimited by international governmental
boundaries. Genetic differences between the population segments being
considered may be used to evaluate discreteness. If a population
segment is considered discrete, its biological and ecological
significance must then be evaluated. Significance is evaluated in terms
of the importance of the population segment to the overall welfare of
the species.
The petition to list the smalltail shark did not provide
information regarding potential DPSs of the smalltail shark or request
that we consider listing any particular population segment. To
determine whether any discrete populations of smalltail sharks exist,
the SRT examined the best available information on smalltail shark
population structure, including tagging, tracking, and genetics
studies. Only one genetic study on the smalltail shark exists (Tavares
et al., 2013), and that study did not examine population structure and
only examined smalltail shark samples collected off of the Brazilian
state of Par[aacute]. There was no available information on smalltail
shark population structure, movement ecology, or migratory behavior.
The team found no information indicating that major barriers to the
species' dispersal that would result in marked separation between
potential populations or that smalltail sharks were not a panmictic
population across its known range. Overall, the SRT, based on the best
available information, did not find evidence to support the existence
of discrete populations of smalltail sharks. We agree that there are no
population segments of the smalltail shark that would qualify as a DPS
under the DPS Policy.
Similarity in Appearance
The petition to list the smalltail shark requested that we use the
authority under section 4(e) to list species that are similar in
appearance to smalltail sharks. Section 4(e) of the ESA (16 U.S.C.
1533(e)) provides that the Secretary may, by regulation of commerce or
taking, and to the extent he deems advisable, treat any species as an
endangered or threatened species even though it is not listed pursuant
to section 4 of the ESA if: (A) such species so closely resembles in
appearance, at the point in question, a species that has been listed
pursuant to section 4 of the ESA that enforcement personnel would have
substantial difficulty differentiating between the listed and unlisted
species; (B) the effect of this substantial difficulty is an additional
threat to an endangered or threatened species; and (C) such treatment
of an unlisted species will substantially facilitate the enforcement
and further the policy of this chapter. As previously described in the
Life History, Ecology, and Status of the Petitioned Species section,
sharks of the genus Rhizoprionodon (sharpnose sharks) are similar to
the smalltail shark in size and placement of the second dorsal fin in
relation to the origin of the anal fin. However, since we have
determined that smalltail shark does not warrant listing as threatened
or endangered, we have similarly determined not to treat sharpnose
sharks as an endangered or threatened species under section 4(e).
Final Listing Determination
Section 4(b)(1) of the ESA requires that NMFS make listing
determinations based on the best scientific and commercial data
available after conducting a review of the status of the species and
taking into account those efforts, if any, being made by any state or
foreign nation, or political subdivisions thereof, to protect and
conserve the species. We have independently reviewed the best available
scientific and commercial information, public comments submitted in
response to the notice of the initiation of a status review (88 FR
33075, May 23, 2023), the status review report (Heublein et al., 2025),
and other published (e.g., Coelho et al., 2025; Farmer 2025) and
unpublished information, and we have consulted with species experts and
individuals familiar with smalltail shark. We considered each of the
statutory factors to determine whether it presented an extinction risk
to the smalltail shark on its own, now or in the foreseeable future,
and also considered the combination of those factors to determine
whether they collectively contribute to the extinction risk of the
species, currently or in the foreseeable future. As previously
explained, we could not identify a significant portion of the species'
range that is threatened or endangered, nor did we find that any DPSs
of the species exist. Therefore, our determination is based on a
synthesis and integration of the foregoing information, factors and
considerations, and their effects on the status of the species
throughout its entire range.
We have determined the smalltail shark is not presently in danger
of extinction, nor is it likely to become so in the foreseeable future
throughout all or a significant portion of its range. Therefore, the
smalltail shark does not meet the definition of a threatened species or
an endangered species and does not warrant listing as threatened or
endangered. This finding is consistent with the statute's requirement
to base our findings on the best scientific and commercial data
available, summarized and analyzed above.
This is a final action, and, therefore, we are not soliciting
public comments.
References
A complete list of the references used in this 12-month finding is
available upon request, and also available at: https://www.fisheries.noaa.gov/species/smalltail-shark.
Peer Review
In December 2004, the Office of Management and Budget (OMB) issued
a Final Information Quality Bulletin for Peer Review establishing
minimum peer review standards, a transparent process for public
disclosure of peer review planning, and opportunities for public
participation. The OMB Bulletin, implemented under the Information
Quality Act (Pub. L. 106-554) is intended to enhance the quality and
credibility of the Federal Government's scientific information, and
applies to influential or highly influential scientific information
disseminated on or after June 16, 2005. To satisfy our requirements
under the OMB Bulletin, we received peer reviews from three independent
peer reviewers on the status review report (Heublein et al., 2025),
which are available online (https://www.noaa.gov/organization/information-technology/peer-review-plans). All peer reviewer comments
were addressed prior to dissemination of the final status review report
and publication of this 12-month finding. We conclude that these
experts' reviews satisfy the requirements for ``adequate [prior] peer
review'' contained in the bulletin (sec. II.2.).
Authority: The authority for this action is the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).
Dated: July 23, 2026.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine
Fisheries Service.
[FR Doc. 2026-15204 Filed 7-27-26; 8:45 am]
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