[Federal Register: January 26, 2004 (Volume 69, Number 16)]
[Page 3592-3598]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

Endangered and Threatened Wildlife and Plants; 12-Month Finding 
for a Petition To List the Midvalley Fairy Shrimp as Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding for a petition to list the midvalley fairy shrimp 
(Branchinecta mesovallensis) under the Endangered Species Act of 1973, 
as amended. After reviewing the available scientific and commercial 
information, we find that listing is not warranted at this time. We ask 
the public to submit to us any new information that becomes available 
concerning the status of or threats to the species. This information 
will help us monitor and encourage the conservation of this species.

DATES: The finding announced in this document was made on January 20, 
2004. Although further listing action will not result from this 
finding, we request that you submit new information concerning the 
status of or threats to this species whenever it becomes available.

ADDRESSES: The complete file for this finding is available for 
inspection, by appointment, during normal business hours, at the 
Sacramento Fish and Wildlife Office, U.S. Fish and Wildlife Service, 
2800 Cottage Way, Sacramento, CA 95825-1846. Submit new information, 
materials, comments, or questions concerning this species to the 
Service at the above address.

FOR FURTHER INFORMATION CONTACT: Glen Tarr or Arnold Roessler, at the 
Sacramento Fish and Wildlife Office (see ADDRESSES section above), by 
telephone at (916) 414-6600, by facsimile at (916) 414-6712, or by 
electronic mail at mvfairyshrimp@fws.gov.



    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition 
to revise the List of Threatened and Endangered Species that contains 
substantial scientific and commercial information that listing may be 
warranted, we make a finding within 12 months of the date of the 
receipt of the petition on whether the petitioned action is (a) not 
warranted, or (b) warranted, or (c) warranted but precluded by other 
pending proposals. Such 12-month findings are to be published promptly 
in the Federal Register.
    On August 31, 2001, we received a petition dated August 14, 2001, 
from the Center for Biological Diversity and VernalPools.Org, 
requesting us to list the midvalley fairy shrimp as an endangered 
species. On April 29, 2003, we announced an initial petition finding in 
the Federal Register that the petition presented substantial 
information to indicate the petitioned action may be warranted (68 FR 
22724). In accordance with section 4(b)(3)(A) of the Act, we have now 
completed a status review of the best available scientific and 
commercial information on the species, and have reached a determination 
regarding the petitioned action. This determination meets deadline 
requirements established by a court-approved consent decree (Butte 
Environmental Council v. Wayne White, Consent Decree, CIV.S-00-797 

Species Information

    The midvalley fairy shrimp is a small (0.28 to 0.79 inch (in), (7 
to 20 millimeter (mm)) freshwater crustacean found in shallow ephemeral 
pools (pools that seasonally fill and dry up) near the middle of 
California's Central Valley (Helm 1998; Eriksen and Belk 1999; Belk and 
Fugate 2000). It swims on its back by beating its phyllopods, which are 
legs with leaflike or paddlelike structures. The moving phyllopods also 
extract oxygen from the water, along with floating bits of food such as 
phytoplankton and detrital bacterial colonies.
    The midvalley fairy shrimp was only recently formally described as 
a species by Belk and Fugate (2000). Adult males of the species most 
closely resemble male Conservancy fairy shrimp (Branchinecta 
conservatio), while adult females more closely resemble female vernal 
pool fairy shrimp (Branchinecta lynchi). Distinguishing characteristics 
include differently shaped second antennae for males, and the absence 
of a pair of bumps on the third thoracic segments of females (Belk and 
Fugate 2000). Both of these characteristics can not be confirmed 
through visual observation in the field.

Range and Distribution

    Midvalley fairy shrimp have been found in the following California 
counties: Sacramento, Solano, Contra Costa, San Joaquin, Madera, 
Merced, Fresno and Yolo (Belk and Fugate 2000; California Natural 
Diversity Database (CNDDB) 2003a). The known occurrences of midvalley 
fairy shrimp are distributed in five different Vernal Pool Regions as 
described by Keeler-Wolf et al. (1998) (Southeastern Sacramento Valley, 
Livermore, Southern Sierra Foothills, San Joaquin Valley, and the 
Solano-Colusa Region). Each of these regions is classified as having 
different or unique vernal pool characteristics. The area encompassed 
by these regions includes the vernal pool habitats in the San Joaquin 
Valley, the Sierra Nevada foothills from Yuba County south to Kern 
County, the Sacramento Valley from Glenn County south to Santa Clara 
County along the Coast Range. Although the vernal pool grassland 
complexes which are contained within these regions offer unique or 
specific environmental conditions for the species inhabiting them, 
without site specific knowledge of the exact habitat requirements of 
the midvalley fairy shrimp it would be difficult to rule these areas 
out as not being habitat available for the species. Midvalley fairy 
shrimp are distributed within the same vernal pool complexes as other 
listed vernal pool crustaceans (vernal pool fairy shrimp, vernal pool 
tadpole shrimp (Lepidurus packardi), and conservancy fairy shrimp) and 
known habitat preferences for midvalley fairy shrimp can be reasonably 
presumed to fall within the parameters of these listed vernal pool 
    Since we published our 90-day finding on a petition to list the 
species in April, 2003 (68 FR 22724), the CNDDB has documented six new 
sites (two in Yolo County and 4 in Sacramento County). This brings the 
total number of known occurrences from 52 to 58. Additional records not 
recorded in CNDDB have also been documented as a result of surveys in 
east Merced County in 2001 and 2002 (K. Fien, in litt. 2002, CNDDB 
2002, CNDDB 2003). The increase of known locations lends additional 
support to the idea that the range and distribution of midvalley fairy 
shrimp is greater than the distribution of known occurrences. The two 
reported occurrences in Yolo County are in an area previously not known 
to support midvalley fairy shrimp.
    With the exception of eastern Merced County, the range and 
distribution of the midvalley fairy shrimp has been

[[Page 3593]]

poorly documented by surveys. Helm's (1998) survey of large 
branchiopods is the most comprehensive, but the 95 locations surveyed 
in that study are spread out across the northern counties of the state, 
leaving many counties within or on the borders of the midvalley fairy 
shrimp's known range with few or no sampled locations. The known range 
is primarily based on occurrence data submitted to the CNDDB, but such 
data do little to rule out the existence of additional occupied areas 
(CNDDB in litt 2003). Most potentially occupied sites have yet to be 
surveyed for the species, and surveys conducted for other vernal pool 
species can not be relied on to provide midvalley fairy shrimp data to 
the CNDDB. The species is difficult to identify, and was not formally 
described until 2000 (Belk and Fugate 2000). Although survey permits 
for listed vernal pool species now require biologists to submit any 
midvalley fairy shrimp data to the CNDDB, failure to do so would be 
difficult to detect.
    In addition the CNDDB has yet to incorporate data from certain 
surveys conducted in eastern Merced County in 2001 and 2002 that 
specifically looked for midvalley fairy shrimp (among other species) 
(K. Fien, California Department of Fish and Game (CDFG), in litt. 
2002). These surveys are among the most comprehensive conducted for the 
species in the Merced area and produced a great deal of new site data. 
It is difficult to estimate how many new occurrences the additional 
surveys sites represent because CNDDB occurrences combine population 
locations within about 0.25 miles (mi) (0.40 kilometers (km)) (Darlene 
McGriff, CNDDB, pers. comm. 2003), and because some of the additional 
site data include multiple records at the same location (John Hunter, 
Restoration Ecologist, Jones and Stokes, pers comm. 2003). However, 
visual examination of the new locations using Geographic Information 
Systems (GIS) software shows a fairly continuous distribution of new 
sightings running from the proposed UC Merced area to Myer's Ranch, 
about 6 mi (9.7 km) to the east. New sightings also show up in the area 
of the Cunningham Ranch, about 10 mi (16 km) east by southeast of the 
UC Merced site, and also in a relatively small area at the southeast 
corner of the County about 20 mi (32 km) southeast of the UC Merced 
site. The total area roughly encompassed by new sightings not yet 
included in the CNDDB is approximately 25 square miles (mi\2\) (65 
square kilometers (km\2\)) or 15,600 acres (ac) (6,475 hectares (ha)).
    The extent which a species is threatened depends on numerous 
factors including the species' range and distribution. Vernal pool 
fairy shrimp species such as midvalley and the other listed 
Branchinecta are cryptic in nature and often require several years of 
surveying to identify occupied and unoccupied habitat. Also these 
species (especially the vernal pool fairy shrimp) tend to experience 
local extirpation and colonization events overtime within and between 
the vernal pool habitats and complexes in which it is found. As a 
result, a species may not express itself on a regular basis in every 
vernal pool or vernal pool complex it is found. During the process to 
list the four vernal pool crustaceans, the original distribution and 
range of the California fairy shrimp (Linderiella occidentalis) was 
believed to be much more restricted than later found after subsequent 
survey efforts. The California fairy shrimp is subject to the same 
threats of habitat loss and alteration as the four listed crustaceans, 
yet due to its range and distribution is more widespread and not under 
threat of extinction. Subsequently, the final rule to list excluded the 
California fairy shrimp and designated the vernal pool fairy shrimp as 
threatened from endangered (59 FR 48136, September 19, 1994). Similarly 
the vernal pool clam shrimp (Cyzicus sp.) also occurs in vernal pools, 
is under the same threats as other vernal pool species yet is well 
distributed and well documented throughout its range and not under 
threat of extinction. As discussed above, the range and distribution of 
the midvalley fairy shrimp is not well established due to its recent 
description as a species and may conceivably be much more extensive 
than indicated by currently available information.
    The vernal pool habitat within Stanislaus and San Joaquin Counties 
provides specific examples that midvalley fairy shrimp may be more 
widespread than currently documented (CNDDB 2003). Both these counties 
have relatively large tracts of habitat (as discussed below), including 
rangeland on their eastern margins (University of California 1998) with 
mapped vernal pool areas containing widely scattered smaller pools and 
closely packed (high density) pools of varying sizes (Holland 1998). 
They also include Riverbank geologic formations, as well as other 
formations shown by surveys in east Merced County to support midvalley 
fairy shrimp populations (CDMG 1981, CDMG 1991, Vollmar 2002). The 
current survey protocols for the listed vernal pool crustaceans 
requires that permitees stop netting vernal pools once a positive 
identification of a listed species has been recorded. This would result 
in portions of a vernal pool complex not being specifically surveyed. 
Also the frequency of sampling outlined in the protocols may also 
result in negative detections of midvalley fairy shrimp due to their 
ability to complete their lifecycle within a short time frame (Service 
Eriksen and Belk 1999). With the similarity of physical characteristics 
between midvalley and other Branchinecta species it would be difficult 
at best to identify the species only through visual observation of the 
    We attempted to address these problems in 2001 by commissioning a 
rangewide midvalley fairy shrimp survey, but although the survey did 
find some new populations, the survey was not conducted comprehensively 
or systematically. Also, most of the sightings found merely served to 
confirm population sites that were already in the published literature. 
The survey therefore did little to verify range or distribution limits 
of the species (Jan Knight, Service, in litt. 2002). We are currently 
funding a new survey to complete this work and are working closely with 
the contractors to ensure use of a reliable sampling methodology 
capable of supporting conclusions regarding both absence and presence 
of midvalley fairy shrimp in surveyed areas.


    Midvalley fairy shrimp live primarily in vernal pools, but 
occasionally may also be found in vernal swales and other ephemeral 
wetlands such as roadside puddles (Helm 1998; Belk and Fugate 2000; 
Vollmar 2002; CNDDB 2003). Vernal pools are shallow depressions with 
relatively impermeable soils that pond water during the winter and 
early spring, dry down during the spring, and are completely dry by the 
late spring or early summer. Vernal pools support a specific community 
of plants and animals adapted to such conditions (Keeler-Wolf et al. 
1998). Vernal swales are similar to vernal pools, but tend to convey 
surface runoff during wet seasons in shallow, vegetated channels. 
Vernal swales may interconnect vernal pools to form a matrix of swale 
and pool features called a vernal pool complex (Helm 1998). The 
majority of sightings of this species have been in vernal pools. For 
instance, a survey conducted in the early 1990s for large branchiopods 
in 27 California counties found 13 midvalley fairy shrimp occurrences 
in vernal pools (Helm 1998) and one in a vernal swale. A 2002 survey of 
eastern Merced County found midvalley fairy shrimp in 72 locations,

[[Page 3594]]

all of which were vernal pools (Vollmar 2002). A survey in 2000 
documented several midvalley fairy shrimp occurrences in vernal pools, 
roadside drainages, and along a railroad easement (Rogers 2001).
    Generally, the species appears to require shallow vernal pools with 
low to moderate dissolved salts (Eriksen and Belk 1999). Cysts appear 
to hatch best in cool water (about 10 degrees Celsius 
(C) (50 degrees Fahrenheit (F))), though 
adults have exhibited a high tolerance for warmer water conditions, and 
Helm (1998) found one occurrence in water that was 32 C 
(90 F) (Helm 1998; Eriksen and Belk 1999). A comparison 
of the characteristics of pools used by eight branchiopod species 
endemic to northern California found that midvalley fairy shrimp used 
the shallowest pools, both as determined according to average pool 
depth (4.0 in (10.1 centimeters (cm)) and maximum potential pool depth 
(5.4 in (13.7 cm)) (Helm 1998). It also used pools with the least 
potential ponding area (average of 721 square feet (ft\2\) (67 square 
meters (m\2\)) and total water volume (average of 23,908 cubic feet 
(ft\3\) (677 cubic meters (m\3\)) of all the endemic branchiopods but 
one (that one being the Modoc Plateau tadpole shrimp (Lepidurus sp., 
not yet formally described), which was only found in two pools). 
Another study in Merced County found midvalley fairy shrimp in even 
smaller and shallower pools, averaging 5.1 in (13 cm) maximum ponding 
depth and 229.4 ft\2\ (21 m\2\) maximum ponding area (Vollmar 2002).
    Known midvalley fairy shrimp occurrences most commonly occur on 
``Riverbank'' geologic formations and on low terrace, basin rim, and 
volcanic mudflow landforms (Helm 1998; Vollmar 2002). Landforms are 
surface geomorphic features formed by the deposition of soil and rock 
through flooding, glacial outwash, and volcanic eruptions (Smith and 
Verrill 1998). The landform types frequented by midvalley fairy shrimp 
occur at relatively low elevations with low gradients. Additionally, 
occurrences in eastern Merced County appear to cluster in areas 
containing a dense concentration of vernal pools, as mapped by Holland 
(1998) (CNDDB 2003; Kristi Fien, CDFG, in litt. 2002, as explained by 
Jennifer Housely, Jones and Stokes, in litt. 2003, compiling data from 
Vollmar 2002, EIP Associates 1999, EIP Associates 2001, and URS 2000). 
This association is less clear in the northern portion of the species' 
range, holding fairly well for Solano County, which has a large area of 
high-density habitat, but less well for Sacramento County, which has 
several smaller areas of such habitat at higher elevations. Yolo County 
has two midvalley fairy shrimp occurrences, but has virtually no high 
density vernal pool areas at all. Vollmar (2002) found midvalley fairy 
shrimp on Laguna geological formations, which are more typically found 
underlying high terrace grasslands (Reiner and Swenson 2000). 
Additionally, Helm (1998) found about 20 percent of his midvalley fairy 
shrimp populations on volcanic mudflow landforms underlain by Merhten 
geologic formations. Valley Springs is another geologic formation 
typical of volcanic mudflow landforms (Reiner and Swenson 2000), and 
Vollmar's (2002) study found roughly as many populations on Merhten and 
Valley Springs formations combined, as on Riverbank.
    The apparent tendency of the species to avoid higher elevation 
terraces may conflict with its tendency to occur in smaller pools. 
Vollmar's (2002) stratified random survey of rangeland in eastern 
Merced County found average pool size on higher terraces to be small, 
shallow, and ``seemingly ideal'' for the species. Yet midvalley 
occurrences tended to occur in the smaller pools of the lower terraces, 
where average pool size was medium to large. Across the state, only 
three known population locations occur on soils associated with high 
terrace landforms (USDA 1998; Smith and Verrill 1998; CNDDB 2003). 
These occurrences (occurrences 1, 28, and 45 in the CNDDB) all occur 
within 2.0 mi (3.2 km) of each other in Sacramento County, and are all 
within about 0.5 mi (0.8 km) of the mapped edge of such soils.
    Generally, all the midvalley fairy shrimp habitat requirements and 
correlations appear to fall within the range of habitat used by vernal 
pool fairy shrimp. For instance, midvalley fairy shrimp tend to use 
small, shallow pools, while vernal pool fairy shrimp can use pools that 
are either small or medium (Helm 1998). Helm's (1998) study, for 
example, found midvalley fairy shrimp in pools ranging from 8 to 19 cm 
(3.1 to 7.5 in) maximum ponding depth, and vernal pool fairy shrimp in 
pools of 3 to 122 cm (1.2 to 48 in) maximum ponding depth. Similarly, 
Vollmar's (2002) study in east Merced County found midvalley fairy 
shrimp in pools from 2 to 9 cm (0.79 to 3.5 in) maximum ponding depth, 
and vernal pool fairy shrimp in 2 to 16 cm (0.79 to 6.3 in) pools. 
Vollmar (2002) also found that midvalley fairy shrimp tend to avoid 

high terrace landforms, but found vernal pool fairy shrimp in both high 
and low terrace landforms. Vernal pool fairy shrimp in eastern Merced 
County were also found on every geographic formation and in every area 
of the map (within 1 mi (1.6 km)) where midvalley fairy shrimp were 
found (EIP Associates 2001; Vollmar 2002). In other counties, known 
midvalley fairy shrimp locations also tend to occur within about a mile 
of known vernal pool fairy shrimp locations. The six midvalley fairy 
shrimp occurrences in San Joaquin County are the most serious 
exceptions to this trend. These occurrences were found in marginal 
roadside habitat from 5 to 15 mi (8 to 24 km) away from the nearest 
vernal pool fairy shrimp. Solano County also has four midvalley 
occurrences at distances of 1.5 to 5 mi (2.4 to 8 km) away from vernal 
pool fairy shrimp, and there is one such occurrence each in Contra 
Costa, Sacramento, Fresno, and Madera Counties.

Reproduction and Growth

    As might be expected from a species found in relatively small, 
potentially quick-drying pools, the midvalley fairy shrimp showed the 
fastest maturation rate of all the endemic Northern California 
branchiopods tested (Helm 1998). Interestingly, whereas Helm found that 
midvalley fairy shrimp could reach maturity (defined as having at least 
one individual in the population with apparently functioning sexual 
organs) in as few as 8 days, the average time to maturity was 26.3 
days, which was considerably more than the 18.0 days on average 
required for vernal pool fairy shrimp. Helm relates that the late-
season rain that led to the quickest maturation rate was followed by 
particularly warm weather and eventually resulted in water temperatures 
of 32 C (90 F) in the midvalley fairy 
shrimp's pool. The midvalley fairy shrimp's ability to mature and 
reproduce unusually quickly in warm water, while maintaining a 
maturation rate comparable to other species in cooler water, may allow 
it to take advantage of late spring or early summer storms without 
sacrificing its ability to utilize more long-lived ponds that form 
earlier in the season (Helm 1998). As stated above current survey 
protocols call for surveys to begin during the winter once the pools 
fill and stop once a listed species has been found or the pool dries in 
the spring. The timing and frequency of sampling outlined in the 
protocols may not be able to detect midvalley fairy shrimp occurrences.
    Midvalley fairy shrimp populations survive the seasonal desiccation 
of their ponds by laying eggs encased in nearly impervious shells. 
Embryos within these eggs enter a dormant state called

[[Page 3595]]

diapause, which in related species can last for decades if necessary, 
until such time as their pools refill and proper environmental cues 
allow them to hatch. Dormant eggs are referred to as cysts, and because 
not all cysts hatch with each refilling of a pool, they can form a cyst 
bank (similar to a seed bank) in the soil that produces new populations 
of adult shrimp where none had been seen in years. Since the cysts can 
pass unharmed through the digestive systems of other animals, and since 
they are very small (0.012 in (0.27 mm)), they can be transported to 
new locations by birds or mammals and potentially colonize other vernal 
pools. Cysts also float after having been dried, so they can be washed 
to new locations by flooding (Eriksen and Belk 1999). After hatching, 
the shrimp pass through three stages of growth, called nauplius, 
metanauplius and juvenile, before becoming adults. These stages differ 
primarily in the extent to which the thoracic and abdominal segments 
have developed. For instance, the nauplius lacks thoracic segments and 
their accompanying phyllopods, and so must use its antenna for 
locomotion (Eriksen and Belk 1999).

Discussion of Listing Factors

    Section 4 of the Act (16 U.S.C. 1533) and implementing regulations 
at 50 CFR part 424 set forth procedures for adding species to the 
Federal endangered and threatened species list. A species may be 
determined to be an endangered or threatened species due to one or more 
of the five factors described in section 4(a)(1). These factors and 
their application to midvalley fairy shrimp are as follows:

A. The Present or Threatened Destruction, Modification, or Curtailment 
of Its Habitat or Range

    Midvalley fairy shrimp are potentially vulnerable to the same urban 
and agricultural conversion pressures mentioned in our listing 
determination for the vernal pool fairy shrimp, vernal pool tadpole 
shrimp, Conservancy fairy shrimp, and longhorn fairy shrimp (B. 
longiantenna) (Service 1994). Holland (1998) documented average annual 
losses of vernal pool complexes by county ranging from 0 to over 30,000 
ac (12,140 ha) per year, and averaging about 550 ac (223 ha) per year 
through 1997 in counties known to contain midvalley fairy shrimp. 
Baseline years for each county ranged from 1985 to 1994, however. If we 
include only those counties (Sacramento, Solano, Fresno and Contra 
Costa) whose vernal pool losses can be ascertained from about 1994, 
which was the year the first 4 vernal pool crustaceans were listed (59 
FR 48136, September 19, 1994), the average loss rate drops to 182 ac 
(74 ha) per year. Although this drop in the rate of habitat loss cannot 
be specifically attributed to the listing of the four vernal pool 
crustaceans, the listing and the protections of the Act certainly can 
be attributed to moderating vernal pool losses.
    Of the 58 midvalley fairy shrimp occurrences in the CNDDB (2003), 
23 occurrences (roughly 40 percent) are on protected lands and 14 are 
in rural areas not currently under threat. In addition, approximately 
66 sightings of midvalley fairy shrimp have also been documented as a 
result of surveys in east Merced County in 2001 and 2002 (K. Fien, in 
litt. 2002, CNDDB 2002, CNDDB 2003). Approximately 30 of these 
sightings are on protected lands and 23 are in rural areas not 
currently under threat. The remainder is within the proposed UC Merced 
development area. As discussed in the Range and Distribution section 
above, it is not clear how many CNDDB occurrences these sightings will 
eventually represent; however, after reviewing the point data it is 
reasonable to assume that a majority of the sites will represent new 
occurrences and not confirmations of existing CNDDB records. Taken 
together, the eastern Merced easement lands, which contain known 
midvalley fairy shrimp sightings, total approximately 20,750 ac (8,397 
ha) (Kristi Fien, in litt. 2003). The easements are permanent, will 
generally be managed by the Nature Conservancy, and cannot be 
extinguished by selling the land to a new owner (Jeff Single, 
California Department of Fish and Game, in litt. 2003; Service, in 
litt. 2003). They are also currently independent of any additional 
vernal pool conservation actions to be taken by UC as part of its 
Conservation Strategy for vernal pool species.
    Compared to the vernal pool fairy shrimp and vernal pool tadpole 
shrimp which consistently occur within the range of midvalley fairy 
shrimp this proportion of protection of occurrences is far greater than 
the other listed species. The protected midvalley fairy shrimp lands 
include two national wildlife refuges, several vernal pool conservation 
banks, a California Department of Fish and Game ecological reserve, and 
several Nature Conservancy and CDFG conservation easements. Overall the 
protected sites include representative locations from four of the five 
vernal pool regions occupied by midvalley fairy shrimp (see Habitat, 
above) (Keeler-Wolf et al. 1998), including five sites in Sacramento 
County (Southeastern Sacramento Valley Region), 13 sites in east Merced 
County (Southern Sierra Foothills Region), one site in central Merced 
County (San Joaquin Valley Region), and four sites in Solano and Yolo 
counties (Solano-Colusa Region).
    In east Merced County, 13 CNDDB occurrences are on large land 
parcels protected by conservation easements. The CDFG purchased the 
easements specifically to help mitigate any impacts to vernal pool 
species that might result from construction in the area, particularly 
construction of the University of California (UC), Merced. The only 
portion of the proposed UC which has gone through Service review and 
the section 7 process is the phase 1 of the project. Phase 1 of the 
project occurred on an area which did not result in take to listed 
vernal pool species and as a result no take authorization was given for 
the development. Additional expansion of the UC will require 
consultation with the Service through section 7 of the Act.
    In contrast, we are aware of development plans at various stages of 
completion for nine sites (15.5 percent). Of these nine, none have 
finalized plans to remove the known midvalley fairy shrimp habitat, and 
some are undergoing formal or informal consultation with us under 
section 7 of the Act for potential effects to listed vernal pool 
species. An additional 12 sites are located on habitat that has already 
been largely converted to other uses such as housing developments, 
vineyards or row crops. These sites generally involve relatively small 
remnant patches of habitat surrounded by the new land use. Although 
some of these sites are small, the midvalley fairy shrimp's ability to 
occupy small shallow pools, and its relative heat tolerance, may allow 
it to persist under the modified hydrologic patterns of such areas. 
Freshwater fairy shrimp species such as the midvalley may also be less 
susceptible to inbreeding effects that can threaten small isolated 
populations (Fugate 1998).
    Based on the information available on specific threats, the amount 
of land area protected containing midvalley fairy shrimp occurrences 
either through location on specific vernal pool preserves, wildlife 
refuges, or through conservation easements we believe that the threats 
to the known occurrences of midvalley fairy shrimp are not to a level 
where the species is at risk of becoming extinct through a significant 
portion of its range. Approximately 64 percent of the CNDDB occurrences 
are either protected or are currently not under any identifiable threat 
(23 protected, 14 not specifically threatened). In addition, a

[[Page 3596]]

significant number of sightings in eastern Merced County not included 
in CNDDB are also either protected or not currently under threat. These 
occurrences represent a good cross section of the known range of the 
species and occupy examples of the various vernal pool habitat types 
habitat within four of the five vernal pool regions (Keeler-Wolf et al. 

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    The listing petition acknowledges, and we agree, that current data 
do not indicate that these factors constitute a threat to the midvalley 
fairy shrimp at this time.

C. Disease or Predation

    The listing petition acknowledges, and we agree, that current data 
do not indicate that these factors constitute a threat to the midvalley 
fairy shrimp at this time.

D. The Inadequacy of Existing Regulatory Mechanisms

    The primary cause for the decline of vernal pool species is loss of 
habitat due to human activities. State and Federal laws exist that 
provide some protection to the midvalley fairy shrimp. Existing 
regulatory mechanisms that could provide some protection for the 
midvalley fairy shrimp include: (1) Section 404 of the Federal Clean 
Water Act; (2) occurrence with other species protected by the Federal 
Endangered Species Act; (3) consideration under the California 
Environmental Quality Act (CEQA) and other State regulations; and (4) 
local laws and regulations.


    Clean Water Act (CWA): The Clean Water Act (33 U.S.C. 1251 et. 
seq.) prohibits the discharge of pollutants into ``navigable waters,'' 
which it defines as ``the waters of the United States'' (33 U.S.C. 
1311, 1362). Section 404 of the CWA (33 U.S.C. 1344) provides an 
exception to this general prohibition by authorizing the U.S. Army 
Corps of Engineers (Corps) to issue permits for the discharge of dredge 
or fill material. Regulations issued by the Corps define the term 
``waters of the United States'' to include ``wetlands * * * the use, 
degradation or destruction of which could affect interstate or foreign 
commerce'' (33 CFR 328.3). Under this authority, the Corps has 
regulated the discharge of fill material into vernal pools, except for 
discharges specifically exempted by the CWA, such as those resulting 
from ``normal farming, silvicultural and ranching activities'' (33 
U.S.C. 1344(f)(1)(A)). The CWA requires project proponents to obtain a 
permit from the Corps prior to undertaking many activities (e.g., 
grading, discharge of soil or other fill material) that would result in 
the filling of wetlands subject to the Corps' jurisdiction. However, in 
light of a recent Supreme Court decision (Solid Waste Agency of 
Northern Cook County v. U.S. Army Corps of Engineers No. 99-1178, 2001 
(SWANCC)), the Corps' Sacramento District Office, which administers the 
section 404 permit process across the known range of the midvalley 
fairy shrimp, no longer requires section 404 permits for filling in 
vernal pools unless those pools are connected at some time by overland 
flow to navigable waters or their tributaries. The district office is 
determining which pools will require permits on a case-by-case basis, 
and estimates that ``most'' of the vernal pools in the district will 
remain subject to section 404 regulations (Nancy Haley, Corps 
Sacramento District Office, pers. comm. 2003).
    For pools and discharges requiring permits, the section 404 process 
provides three levels of review. Projects involving fill of more than 
0.5 ac (0.2 ha), or which may affect listed species or otherwise have 
more than a minimal adverse effect on the environment, require 
individual permits. The Corps issues such permits on a case-by-case 
basis according to guidelines established at 40 CFR part 230. 
Guidelines particularly applicable to vernal pool protection include 
requirements that: (1) No practicable alternatives exist with less 
environmental impact; (2) the project comply with the Endangered 
Species Act; (3) the project not contribute to significant water 
quality degradation as measured by impacts to (among other things) 
wildlife health and ecosystem diversity; and (4) appropriate and 
practicable steps be taken to minimize adverse impacts. Such 
appropriate and practicable steps may include the creation and 
protection of vernal pools in mitigation banks (60 FR 58605, July 31, 
    Smaller projects with minimal adverse effects may be issued a 
general permit. Such permits contain standardized provisions for 
particular types of projects within a particular region or across the 
nation. The general permits most applicable to midvalley fairy shrimp 
are nationwide permits (NWPs) 39 and 40, which authorize discharges due 
to development and to nonexempted agricultural activities respectively 
(67 FR 2019, January 15, 2002). General permits are the most common 
type issued, and require less review by the Corps than individual 
permits (Ruffolo 2002). Provisions in both NWP 39 and 40 also provide 
for the lowest level of review, under which wetlands of up to 0.1 ac 
(0.04 ha) may be filled without prior notification to the Corps if 
other requirements of the permit are met.
    Available information indicates the section 404 permit process in 
some cases may be relatively effective at protecting wetlands under its 
jurisdiction (Ruffolo 2002). Such information, however, does not 
account for projects that do not come under permit review, such as 
vernal pool fill associated with normal farming or ranching practices. 
The tendency for midvalley fairy shrimp to occur on Riverbank 
formations and other low terrace land forms would subject the species 
and its habitat to a high degree of agricultural development pressure. 
In reviewing the information on habitat preferences for midvalley fairy 
shrimp for shallow vernal pool habitats and the fact that some of the 
occurrences are already isolated due to habitat fragmentation it is 
questionable that the Corps would take jurisdiction over the pools 
inhabited by midvalley fairy shrimp.
    Considering the potential continued trend of vernal pool losses 
throughout the state and the questions raised regarding jurisdiction 
over vernal pools, it is possible that the regulatory mechanisms 
provided under the CWA may provide some minimal protection to the 
midvalley fairy shrimp.

Endangered Species Act

    The Act will afford incidental protection to midvalley fairy shrimp 
where they co-exist with species already listed as threatened or 
endangered. Fleshy owl's-clover (Castilleja campestris ssp. 
succulenta), Solano grass (Tuctoria mucronata), Colusa grass (Neostafia 
colusana), Conservancy fairy shrimp, vernal pool tadpole shrimp, and 
vernal pool fairy shrimp, are listed as threatened or endangered under 
the Act and occur in some of the same habitat as the midvalley fairy 
shrimp. Consequently, prospective developers requiring a Federal permit 
(such as a permit to fill vernal pools under section 404 of the CWA, 33 
U.S.C. 1344 et seq.) would already be required to survey for listed 
species prior to developing midvalley fairy shrimp pools in those 
quadrangles. This could lead to consultation requirements prior to 
destruction or modification of midvalley fairy shrimp pools, if those 
pools or their associated complexes also support occurrences of listed 
shrimp. When

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considering the occupancy of vernal pool grasslands with listed vernal 
pool crustaceans we evaluate the biological and physical factors 
associated with the vernal pool wetland. Factors such as proximity to 
adjacent vernal pools, watersheds, hydrology, number of occurrences, 
connectivity with other vernal pools, wetland swales, and extent of the 
associated uplands are evaluated. As a result of this evaluation 
occupancy is usually considered within the complex and not isolated to 
an individual pool. This distribution occurs because different areas of 
the cyst bank hatch at different times in response to local conditions 
(59 FR 48136, September 19, 1994; Eriksen and Belk 1999). However, none 
of these species except the vernal pool fairy shrimp have been found to 
co-occur with midvalley fairy shrimp in the same vernal pools (Eriksen 
and Belk 1999) and this observation is believed to be a result of 
overland flow in a heavy precipitation event and not as a result of 
overlapping habitat requirements. Biological surveys are often 
inadequate and project proponents may miss detection of midvalley fairy 
shrimp due to its ability to occur in shallow pools which are inundated 
for short periods. In instances where coexistence of listed species and 
midvalley fairy shrimp are documented in the same complex, there may be 
incidental protection although there is no consultation requirement to 
avoid take or minimize effects of the action on the midvalley fairy 


    California Environmental Quality Act (CEQA): The California 
Environmental Quality Act (Public Resources Code Sec. 21000-21177) 
requires a full disclosure of potential environmental impacts of 
proposed projects and offers broad opportunities to protect rare, 
threatened, endangered plants or animals and their habitats. Federally 
listed animals are considered rare, threatened, or endangered for 
purposes of CEQA (14 CCR 15380), which means that habitat protections 
taken under CEQA for the vernal pool fairy shrimp may also benefit the 
midvalley fairy shrimp in the same manner as discussed above with 
regard to the Act. In addition CEQA protects the environment more 
generally and broadly than the Endangered Species Act and mitigates all 
impacts to the environment. Protection of habitat under CEQA does not 
require the species be listed under the Endangered Species Act.
    The public agency with primary authority or jurisdiction over a 
proposed project is designated as the lead agency and is responsible 
for conducting a review of the project and consulting with other 
agencies concerned with the resources affected by the project. Section 
15065 of the CEQA guidelines requires a finding of significance if a 
project has the potential to ``reduce the number or restrict the range 
of a rare or endangered plant or animal.'' Once significant effects are 
identified, the lead agency may either require changes in the project 
to mitigate the effects, or else in rare instances may decide that 
overriding social or economic considerations make mitigation 
infeasible. Projects approved under the latter circumstances are still 
required to mitigate. However, as a result without the fail safe of a 
jeopardy prohibition, projects may be approved that cause environmental 
damage, such as the destruction of rare species or their habitats. 
Protection of listed or rare species through CEQA is, therefore, 
dependent upon the discretion of the agency involved and available 
mitigation with no absolute protection. CEQA will therefore contribute 
to the protection of midvalley fairy shrimp habitat, but there may be 
instances where ``overriding considerations'' result in destruction, 
albeit mitigated, of midvalley fairy shrimp habitat.
    The California Department of Fish and Game (CDFG) is the agency 
responsible for managing and regulating fish and wildlife resources in 
California. CDFG's mission is to manage California's diverse fish, 
wildlife, and plant resources, and the habitats upon which they depend, 
for their ecological values and for their use and enjoyment by the 
public. CDFG has no officially adopted regulations or statutes 
pertaining to wetlands. However, Fish and Game Code Sec. 1601 and Sec. 
1603 charge CDFG with executing Streambed Alteration Agreements. As a 
designated Trustee and/or Responsible Agency under CEQA Sec. 15386 and 
Sec. 15381, CDFG reviews and comments on documents produced by the lead 
agencies. These regulations only apply to streams and stream corridors 
and are not mechanisms which would protect upland areas and vernal pool 


    We are not aware of any specific county or city ordinances or 
regulations that provide protection for the midvalley fairy shrimp.
    Based on the current level of protections afforded wetland habitats 
through the CEQA, CWA and the ESA, we believe that the existing 
regulatory mechanisms provide some protection of the midvalley fairy 
shrimp. However, the protections of the ESA are only coincidental and 
the CWA and CEQA while protecting some vernal pool habitat do not 
necessarily protect all of it.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

    We are not aware of any other factors that constitute a threat to 
the midvalley fairy shrimp at this time.

Petition Finding

    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
faced by this species. We reviewed the petition, information available 
in our files, other published and unpublished information, and comments 
submitted to us during the public comment period following our 90-day 
petition finding, and we consulted with recognized vernal pool 
crustacean experts and other resource agencies. On the basis of the 
best scientific and commercial information available, we find that the 
proposal to list the midvalley fairy shrimp is not warranted at this 
time. Although vernal pool habitat continues to be lost in parts of the 
midvalley fairy shrimp's range, from what we know of the current range 
and distribution of the species, it is well represented by occurrences 
on protected lands and with occurrences in areas with little or no 
current threat. Additionally, although several development projects and 
land use changes are affecting known occurrences, their effects are 
being mitigated and we are not aware of any occurrences likely to be 
extirpated in the near future due to habitat loss. While the existing 
regulatory mechanisms under CEQA, the CWA, and the ESA do not ensure 
protection of midvalley fairy shrimp, they are likely to moderate the 
rate and extent of habitat loss for midvalley fairy shrimp through 
their direct application and as an indirect benefit of conservation 
efforts undertaken for the other listed vernal pool crustaceans. As a 
result of these factors we find that the species is not in danger of 
extinction in the foreseeable future.
    We will continue to monitor the status of the species, and to 
accept additional information and comments from all concerned 
governmental agencies, the scientific community, industry, or any other 
interested party concerning this finding.


    A complete list of references used in the preparation of this 
finding is available upon request from the

[[Page 3598]]

Sacramento Fish and Wildlife Office (see ADDRESSES section).


    The primary author of this document is the Sacramento Fish and 
Wildlife Office, U.S. Fish and Wildlife Service (see ADDRESSES 


    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: January 20, 2004.
Marshall P. Jones Jr.,
Director, Fish and Wildlife Service.
[FR Doc. 04-1510 Filed 1-23-04; 8:45 am]