[Federal Register Volume 61, Number 202 (Thursday, October 17, 1996)]
[Proposed Rules]
[Pages 54145-54147]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-26633]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 679

[I.D. 100996A]
RIN 0648-AI63


Fisheries of the Exclusive Economic Zone off Alaska; Definition 
of Overfishing

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice of availability of amendments to fishery management 
plans; request for comments.

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SUMMARY: These amendments would revise definitions of acceptable 
biological catch (ABC) and overfishing levels (OFLs) for groundfish 
species or species groups. The North Pacific Fishery Management Council 
(Council) has submitted Amendment 44 to the Fishery Management Plan for 
Groundfish of the Gulf of Alaska (GOA) and Amendment 44 to the Fishery 
Management Plan for the Groundfish Fishery of the Bering Sea and 
Aleutian Islands Area (BSAI) (FMPs). This action is necessary to ensure 
that conservation and management measures continue to be based upon the 
best scientific information available and is intended to advance the 
Council's ability to achieve, on a continuing basis, the optimum yield 
from fisheries under its jurisdiction. NMFS is requesting comments from 
the public on the proposed amendments, copies of which may be obtained 
from the Council (see ADDRESSES).

DATES: Comments on Amendments 44/44 must be submitted by December 10, 
1996.

ADDRESSES: Comments on the FMP amendments should be submitted to Ronald 
J. Berg, Chief, Fisheries Management Division, Alaska Region, NMFS, 
P.O. Box 21668, Juneau, AK 99802, Attn: Lori Gravel, or delivered to 
the Federal Building, 709 West 9th Street, Juneau, AK. Copies of 
Amendments 44/44 and the environmental assessment (EA) and related 
economic analysis prepared for the proposed action are available from 
the North Pacific Fishery Management Council, 605 W 4th Ave., Suite 
306, Anchorage, AK 99501-2252; telephone: 907-271-2809.

FOR FURTHER INFORMATION CONTACT: James Hale, 907-586-7228.


[[Page 54146]]


SUPPLEMENTARY INFORMATION: The Magnuson Fishery Conservation and 
Management Act (Magnuson Act) requires that each Regional Fishery 
Management Council submit any FMP or plan amendment it prepares to NMFS 
for review and approval, disapproval, or partial disapproval. The 
Magnuson Act also requires that NMFS, after receiving a fishery 
management plan or amendment, immediately publish a document in the 
Federal Register that the fishery management plan or amendment is 
available for public review and comment. This action constitutes such 
notice for Amendments 44/44 to the FMPs.
    Section 301(a) of the Magnuson Act establishes national standards 
for fishery conservation and management and requires that all fishery 
management plans create management measures consistent with those 
standards. National Standard 1 requires that conservation and 
management measures shall ``prevent overfishing while achieving, on a 
continuing basis, the optimum yield'' from fisheries in Federal waters. 
National Standard 2 requires further that conservation and management 
measures be based on the best scientific information available.
    The Magnuson Act includes a general definition of overfishing, but 
does not establish specific measures for determining where overfishing 
may occur. Pursuant to Sec. 301(b) of the Magnuson Act, the Secretary 
of Commerce issued advisory guidelines (codified at 50 CFR part 600, 
subpart D) that provide comprehensive guidance for the development of 
fishery management plans and amendments. An amendment to the advisory 
guidelines (54 FR 30826, July 24, 1989) requires that fishery 
management plans specify an objective and measurable definition of 
overfishing for each managed stock or stock complex and provide for an 
analysis of how the definition was determined and how it relates to 
biological potential. The guidelines require that an overfishing 
definition will: (1) Have sufficient scientific merit, (2) be likely to 
protect the stock from closely approaching or reaching an overfished 
status, (3) provide a basis for objective measurement of the status of 
the stock against the definition, and (4) be operationally feasible. 
See 50 CFR Sec. 600.310(c)(5).
    In response to the national standards and advisory guidelines, the 
Council developed an objective and measurable definition of overfishing 
and, in 1991, implemented that definition under Amendments 16 and 21 to 
the FMPs (56 FR 2700, January 24, 1991). In the years since 
implementation of that definition, fishery scientists have had the 
opportunity to evaluate the efficacy of current definitions of ABC and 
OFL. In light of that experience and with increased understanding of 
the reference fishing mortality rates used to define ABCs and OFLs, 
fishery scientists have raised several concerns about the present 
definitions and the extent to which they reflect and account for levels 
of uncertainty about fish stock populations. Consequently, NMFS' 
Overfishing Definitions Review Panel (ODRP) and the Council's 
Scientific and Statistical Committee (SSC) recommended redefining ABC 
and overfishing to facilitate more conservative, risk-averse management 
measures when stock size and mortality rates are not fully known.
    The ODRP and SSC recommended that a new definition of overfishing 
should: (1) Compensate for uncertainty in estimating fishing morality 
rates at a level of maximum sustainable yield (MSY) by establishing 
fishing mortality rates more conservatively as biological parameters 
become more imprecise; (2) relate fishing mortality rates directly to 
biomass for stocks below target abundance levels, so that fishing 
mortality rates fall to zero should a stock become critically depleted; 
and (3) maintain a buffer between ABC and the OFL. Accordingly, stock 
assessment scientists at the NMFS Alaska Fisheries Science Center have 
developed new proposed definitions consistent with these 
recommendations.

Revised Definitions of ABC and Overfishing

    The proposed definitions involve sophisticated statistical analyses 
of fish population dynamics. The analyses develop a series of six 
levels or tiers of reliable information available to fishery 
scientists. OFLs would be determined according to the tier that best 
characterizes the available information.
    The first tier, operating on the best available information, 
requires estimates of biomass and biomass at the level of MSY and a 
reliable description of the uncertainty (or probabilities) attending 
the variables involved in calculating fishing mortality at the level of 
MSY. Uncertainty is described by the distribution density of probable 
values: the more widely distributed the probable values, the more 
uncertainty exists in estimating which value most closely approximates 
the true value. Conversely, when probable values are clustered in a 
relatively small range, greater certainty exists that any one of these 
values represents a close approximation of the true value.
    In tier (1), ABC and OFLs are set by deriving two different 
statistical means or averages from the probable values for fishing 
mortality at MSY. The OFL is set at the arithmetic mean (the same as a 
common ``average''), and the ABC is set at the harmonic mean, which 
results typically in a lower value than the common average. The 
harmonic mean grows increasingly lower in relation to the average as 
the probable values become more widely distributed. For example, the 
average for the series of values 3, 4, 5, 6, and 7 is 5; the harmonic 
mean for the same series of values is 4.57. The series of values 1, 2, 
5, 8, and 9, for which the average is also 5, produces in contrast a 
harmonic mean of 2.58.
    When applied to the range of probable values for fishing mortality 
at MSY, the harmonic mean would produce a value for ABC that becomes 
increasingly lower in relation to the OFL as the uncertainty in 
approximating the true value for fishing mortality increases. This 
process creates a buffer between ABC and OFL to protect the stock 
against uncertainty in management parameters and against overly 
aggressive harvest. Conversely, when the probable values for fishing 
mortality are clustered within a relatively small range, greater 
probability (i.e., less uncertainty) exists that the true value for 
fishing mortality will be approximated. In that case, the buffer 
between ABC and overfishing would decrease appropriately.
    If the probabilities (i.e., the amount of uncertainty) cannot be 
reliably assessed for variables associated with fishing mortality at 
MSY, the remaining tiers provide, in descending order, for 
determination of ABC and OFLs with increasingly limited information. 
For tiers (1) and (2), the target abundance level is the size of the 
biomass necessary to produce MSY. Tier (3) provides for stocks for 
which reliable estimates of biomass at MSY are not available by setting 
the target abundance level at an estimate of the long-term average 
biomass that would be expected under average recruitment and a fishing 
mortality rate that would reduce the lifetime spawning stock to 40% of 
what it would be in the absence of fishing. Tiers (4) - (6) provide for 
stocks where target abundance levels cannot be known.
    In tiers (2) - (5), ABC and OFL would be determined by reliable 
information on point estimates of biological factors: biomass (tiers 
(2) - (5)); fishing mortality rates at MSY (tier (2)); long-term 
average biomass under average recruitment (tier (3)); percentages of 
the level of spawning per recruit necessary to maintain the biomass in 
the absence of

[[Page 54147]]

any fishing (tiers (2) - (4)), or natural mortality (tier (5)). In each 
of tiers (2) - (5), ABC is set substantially lower than the OFL, in the 
case of moderately depleted stocks, by being correlated to biomass 
size. In the case of severely depleted stocks, tiers (1) - (4) set ABC 
and OFL at zero. When biological information is extremely limited, tier 
(5) establishes an ABC level at 25 percent below the natural mortality 
rate.
    The sixth and final tier applies to stocks for which the only 
reliable information available is catch history. In such cases, the OFL 
would be set as the average catch from 1978 through 1995, unless an 
alternative value is established by the SSC on the basis of the best 
available scientific information, and ABC would be set lower than or 
equal to 75 percent of that OFL.
    Under the current definitions, the OFL is set equal to the average 
catch between 1977 and the current year in the absence of reliable 
biological information. As long as catch never exceeds that OFL, this 
forces the OFL to decrease over time. The SSC expressed concern that 
OFL should instead remain constant over time when catch history is the 
only information available. By setting terminal years at 1978 and 1995, 
the proposed definition would create a constant OFL for applicable 
fisheries.
    Catch history bears no relationship to biomass levels. However, in 
the absence of reliable biological information that would provide 
indicators about stock levels, catch history offers the only 
alternative, quantifiable information by which to manage a fishery. 
Tier (6) specifically provides for management of a fishery for which 
scientists have no other reliable and quantifiable information to 
indicate stock levels. In developing this final tier, the Council 
wanted to allow for the possibility that other information may become 
available that, while insufficient to establish OFL by a higher tier, 
would provide a more accurate assessment of stock levels. In this 
event, tier (6) allows for such information to supersede catch history 
in determining ABC and OFLs.
    Under the proposed revision, the SSC has responsibility for 
determining the reliability of information by using either objective or 
subjective criteria. The formal review process for a proposed 
definition of overfishing requires, prior to NMFS approval, 
certification by the Director, Alaska Fisheries Science Center, NMFS 
(Science Director), that the proposed definition complies with 
guidelines provided at 50 CFR 600.310(c)(5). These guidelines provide 
that an overfishing definition must: (1) Have sufficient scientific 
merit, (2) is likely to protect the stock from closely approaching or 
reaching an overfished status, (3) provides a basis for objective 
measurement of the status of the stock against the definition, and (4) 
is operationally feasible. The Science Director has certified that this 
proposed definition of overfishing complies with each factor of the 
guidelines, based on the following rationale.

Scientific Merit

    The scientific merit of Amendments 44/44 can be established on the 
basis of both internal and external evidence. Internally, evidence is 
provided by the extremely thorough scientific analysis of the new 
definition contained in the EA and the economic analysis, both in the 
main text and in the appendices. In addition, these documents cite 
examples from the scientific literature which support the new 
definition. External evidence comes in the form of peer review from the 
scientific community. Because the existing definitions of ABC and the 
OFL have been in place for several years, there has been ample 
opportunity for scientific review thereof. For example, the existing 
definitions have been reviewed by the Council's BSAI and GOA Plan 
Teams, the Council's SSC, and NMFS' ODRP. Each of these bodies consists 
at least in part of scientific experts in the field of marine fish 
stock assessment. The ODRP in particular was constituted explicitly for 
the purpose of providing expert scientific review of overfishing 
definitions developed pursuant to the guidelines contained in 50 CFR 
Sec. 600.305. The definitional changes contained in Amendment 44/44 are 
in direct response to requests made by the SSC and ODRP. These changes 
have been reviewed and are supported by the BSAI and GOA Plan Teams and 
the SSC. In addition, the material presented in Appendix B of the EA 
and related economic analysis has been presented in three different 
international scientific symposia, in the context of which it has been 
subject to the review of a large number of the world's foremost 
scientific authorities in this area of research.

Effective Action

    One of the important innovations of the new definition is that it 
institutes a mandatory buffer between ABC and OFL in all cases (under 
the existing definition, ABC and OFL can be the same, meaning that 
there is nothing to prevent the stock from being fished right up to the 
OFL). The new definition follows the ODRP's suggestion that management 
targets (ABC in this case) be distinguished clearly from management 
thresholds (OFL). Even if catches caused ABC to be exceeded by a small 
amount, overfishing would not likely result.

Objective Measurement

    The new definition is integrated into the management system in an 
explicit, objective, and measurable way. Each year, stock assessments 
are conducted on every species or assemblage managed under the BSAI and 
GOA groundfish FMPs. Each of these assessments produces quantitative 
values for the catches corresponding to ABC and OFL. Following review 
and possible modification by the Plan Teams and SSC, these are approved 
by the Council, which then adjusts ABC (downward) as appropriate in 
order to arrive at the total allowable catch. Rigorous in-season 
monitoring of the fishery produces a real-time estimate of the 
commercial catch, which is continually compared against the harvest 
specifications to determine whether the fishery can remain open. 
Because the harvest specifications and the commercial catch are 
measured in the same units, the objective basis for comparison of the 
two is clear.

Operational Feasibility

    As noted above, the new definition is tightly integrated into the 
existing management system, as is the existing definition. Insofar as 
the existing definition is operationally feasible, having successfully 
prevented overfishing of the groundfish resources since its 
implementation in 1990, and given that the new definition only improves 
on the existing one (e.g., through imposition of a buffer between ABC 
and OFL to reduce the level of danger implied by a harvest overrun), it 
is straightforward to predict that the new definition will be 
operationally feasible as well.
    NMFS will consider the public comments received during the comment 
period in determining whether to approve the proposed amendments. No 
regulatory changes are necessary to implement these FMP amendments.

    Authority: 16 U.S.C. 1801 et seq.

    Dated: October 11, 1996.
Gary Matlock,
Director, Office of Sustainable Fisheries, National Marine Fisheries 
Service.
[FR Doc. 96-26633 Filed 10-11-96; 3:07 pm]
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