[Federal Register Volume 60, Number 173 (Thursday, September 7, 1995)]
[Proposed Rules]
[Pages 46571-46572]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-22173]



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DEPARTMENT OF THE INTERIOR
50 CFR Part 17


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
for a Petition to List the Mono Lake Brine Shrimp as Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: The Fish and Wildlife Service (Service) announces a 12-month 
finding for a petition to list the Mono Lake brine shrimp (Artemia 
monica) under the Endangered Species Act of 1973, as amended (Act). 
This aquatic crustacean occurs only in Mono Lake, Mono County, 
California. A recent decision by the California State Water Resources 
Control Board to revise the water rights of the City of Los Angeles in 
the Mono Basin has apparently removed the threat of habitat degradation 
to the Mono Lake brine shrimp. As a result of the protections offered 
by this decision, the Service finds that the Mono Lake brine shrimp 
does not meet the definition of an endangered or a threatened species 
at the present time.

DATES: The finding announced in this document was made on July 24, 
1995. Comments from all interested parties will be accepted until 
further notice.

ADDRESSES: Data, information, comments, or questions concerning this 
petition should be sent to the U.S. Fish and Wildlife Service, Field 
Supervisor, Ventura Field Office, 2493 Portola Road, Suite B, Ventura, 
California 93003.

FOR FURTHER INFORMATION CONTACT: Cathy R. Brown (see ADDRESSES section) 
telephone 805-644-1766; facsimile 805/644-3958.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (16 U.S.C. 1531 et seq.), requires that for any petition to 
revise the Lists of Endangered and Threatened Wildlife and Plants that 
contains substantial scientific and commercial information a finding be 
made within 12 months of the date of receipt of the petition on whether 
the petitioned action is: (a) not warranted, (b) warranted, or (c) 
warranted but precluded from immediate proposal by other pending 
proposals. Such 12-month findings are to be published promptly in the 
Federal Register.
    In a petition dated June 16, 1987, and received by the Service on 
June 19, 1987, the Service was requested by Dr. Dennis D. Murphy, of 
the Center for Conservation Biology, Stanford University, to list the 
Mono Lake brine shrimp as an endangered species. The petition cited 
threats to this species that would result from increasing salinity 
caused by continued water diversions from the streams tributary to Mono 
Lake. The Service's 90-day finding, that substantial information 
existed indicating that the petitioned action may be warranted, was 
published in the Federal Register on August 19, 1988 (53 FR 31721). A 
status review was initiated at that time. A timely finding on the 
subject petition was precluded by higher priority listing actions until 
the present time.
    The Mono Lake brine shrimp is a species of fairy shrimp found only 
in Mono Lake, Mono County, located east of the Sierra Nevada Mountain 
Range in northeastern California. It is a branchiopod crustacean in the 
order Anostraca whose members have stalked compound eyes. It is 
characterized by an elongated body trunk of 20 or more segments, and 
the absence of a carapace.
    Mono Lake may be the second oldest continuously existing lake in 
North America with an estimated age ranging from 500,000 to one million 
years (Vorster 1985). It is a terminal lake, that is, a closed system 
with no outlet flows. Lake level is maintained by five principal 
inflowing streams that originate in the Sierra Nevada mountain range 
from meltwater of the previous winter's snowpack. When the net inflow 
is less than the net evaporation, salinity concentrations increase as 
the lake's surface elevation declines. Beginning in 1941, the City of 
Los Angeles Department of Water and Power (Los Angeles) diverted water 
from four of the five streams flowing into Mono Lake for its municipal 
and domestic use. The water exports have caused a decline of 14 meters 
(m) (45 feet (ft)) in lake surface elevation and a 100 percent increase 
in lake salinity (Dana and Lenz 1986). Mono Lake surface elevation was 
about 1,956 m (6,417 ft) above mean sea level and the water salinity 
was about 48 grams per liter (parts per thousand (ppt)) before water 
exports began in 1941 (Vorster 1985, Botkin et al. 1988). Currently, 
the lake surface elevation is about 1,943 m (6,375 ft) with a salinity 
of 100 ppt (M. Davis, Mono Lake Committee, pers. comm., 1994).
    High salinities deleteriously affect Mono Lake brine shrimp 
reproduction. In addition, female age at reproduction increases 
significantly, and the number of ovoviviparous broods per year and 
brood size decrease significantly as salinity increases from 76 ppt to 
118 ppt (Dana and Lenz 1986). Some of these negative effects on adult 
Mono Lake brine shrimp fecundity occur at present lake salinities. At 
the current salinity of about 100 ppt, about 50 percent of Mono Lake 
brine shrimp cysts do not hatch (Dana and Lenz 1986).
    In September 1994, the California State Water Resources Control 
Board issued Water Rights Decision #1631, revising Los Angeles's water 
rights to provide greater protection to public trust values of Mono 
Lake. The State Board's decision establishes an average lake level of 
1,948 m (6,392 ft), with an estimated salinity of 69 ppt. These 
conditions are expected to be beneficial to brine shrimp reproduction 
and should provide adequate protection for the long-term viability of 
the Mono Lake brine shrimp.
    On the basis of the best available scientific and commercial 
information, the Service finds that listing the Mono Lake brine shrimp 
is not warranted because the taxon is not in danger of extinction or 
likely to become so in the foreseeable future. The Service will 
reclassify the Mono Lake brine shrimp as a category 3C candidate for 
listing and will continue to monitor its status. Category 3C candidates 
are those taxa that have proven to be more abundant or widespread than 
previously believed and/or those that are not subject to any 
identifiable threat. If information becomes available indicating that 
the 

[[Page 46572]]
Mono Lake brine shrimp is threatened with extinction, the Service would 
reevaluate this decision.

References

    A complete list of references used in the preparation of this 
finding is available upon request from the Ventura Field Office (see 
ADDRESSES section).

Author

    The primary author of this document is Cathy R. Brown, Ventura 
Field Office (see ADDRESSES section).

Authority

    The authority for this action is the Endangered Species Act (16 
U.S.C. 1531 et seq.)

    Dated: July 24, 1995.
John G. Rogers,
Acting Director, Fish and Wildlife Service.
[FR Doc. 95-22173 Filed 9-6-95; 8:45 am]
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