[Federal Register: February 27, 1998 (Volume 63, Number 39)]
[Rules and Regulations]               
[Page 9967-9974]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



National Oceanic and Atmospheric Administration

50 CFR Part 226


Fish and Wildlife Service

50 CFR Part 17

Endangered and Threatened Wildlife and Plants; Decision on 
Designation of Critical Habitat for the Gulf Sturgeon

AGENCIES: National Marine Fisheries Service, National Oceanic and 
Atmospheric Administration, Commerce; and Fish and Wildlife Service, 

ACTION: Notice of decision on critical habitat designation.


SUMMARY: The National Marine Fisheries Service (NMFS) and the Fish and 
Wildlife Service (FWS), collectively the Services, announce a decision 
on designation of critical habitat for the Gulf sturgeon (Acipenser 
oxyrinchus desotoi), a federally listed threatened species pursuant to 
the Endangered Species Act of 1973, as amended. Based on lack of 
benefit to the species, the Services have determined that critical 
habitat designation is not prudent. This constitutes the Services' not 
prudent finding for the designation of critical habitat for the Gulf 

DATES: The finding announced in this notice was made on February 24, 

ADDRESSES: Information, comments, or questions should be submitted to 
the Field Supervisor, U.S. Fish and Wildlife Service, 6620 Southpoint 
Drive South, Suite 310, Jacksonville, Florida 32216; or the Regional 
Director, U.S. Department of Commerce, National Marine Fisheries 
Service, 9721 Executive Center Drive N., St. Petersburg, Florida 33702. 
The administrative record supporting this decision is available for 
public inspection, by appointment, during normal business hours at the 
above addresses.

FOR FURTHER INFORMATION CONTACT: Dr. Michael M. Bentzien, Assistant 
Field Supervisor, FWS, see ADDRESSES section above or telephone 904/
232-2580, extension 106; or Ms. Colleen Coogan, NMFS, see ADDRESSES 
section above or telephone 813/570-5312.



    The Gulf sturgeon (Acipenser oxyrinchus (=oxyrhynchus) desotoi), 
also known as the Gulf of Mexico sturgeon, is a nearly cylindrical fish 
with an extended snout, ventral mouth, chin barbels, and with the upper 
lobe of the tail longer than the lower. Adults range from 1.8 to 2.4 
meters (m) (6 to 8 feet (ft)) in length, with adult females larger than 
males. It is a subspecies of Atlantic sturgeon, Acipenser oxyrinchus 
(=oxyrhynchus), and is distinguished from Acipenser oxyrinchus 
oxyrinchus, the East Coast subspecies, by its longer head, pectoral 
fins, and spleen. The Gulf sturgeon is restricted to the Gulf of Mexico 
and its drainages, primarily from the Mississippi River to the Suwannee 
River, within the States of Louisiana, Mississippi, Alabama, and 
Florida. Sporadic occurrences are known as far west as Texas (Rio 
Grande), and marine waters in Florida south to Florida Bay (Wooley and 
Crateau 1985, Reynolds 1993). An anadromous species, the Gulf sturgeon 
migrates between fresh and salt water.
    The Services' involvement with the Gulf sturgeon began with 
monitoring and other studies of the Apalachicola River population by 
the FWS Panama City, Florida, Fisheries Assistance Office in 1979. The 
fish was included as a category 2 species in the FWS December 30, 1982 
(47 FR 58454) and September 18, 1985 (50 FR 37958) vertebrate review 
notices and in the January 6, 1989 (54 FR 554) animal notice of review. 
Category 2 designation was given at that time to species for which 
listing as threatened or endangered was possibly appropriate, but for 
which additional biological information was needed to support a 
proposed rule. In 1980, the FWS Jacksonville, Florida, Office 
contracted a status survey report on the Gulf sturgeon (Hollowell 
1980). The report concluded that the fish had been reduced to a small 
population due to overfishing and habitat loss. In 1988, the Panama 
City Office completed a report (Barkuloo 1988) on the conservation 
status of the Gulf sturgeon, recommending that the subspecies be listed 
as a threatened species pursuant to the Act. The Services jointly 
proposed the Gulf sturgeon for listing as a threatened species on May 
2, 1990 (55 FR 18357). In that proposed rule, the Service maintained 
that designation of

[[Page 9968]]

critical habitat was not determinable due to the sturgeon's broad range 
and the lack of knowledge of specific areas utilized by the subspecies. 
The final rule for the Gulf sturgeon was published on September 30, 
1991 (56 FR 49653). It included special rules promulgated under Section 
4(d) of the Act for a threatened species, allowing taking of Gulf 
sturgeon in accordance with applicable State laws, for educational and 
scientific purposes, the enhancement of propagation or survival of the 
species, zoological exhibition, and other conservation purposes. The 
final rule found that critical habitat designation ``may be prudent but 
is not now determinable.'' Further comments on the critical habitat 
issue were solicited from all interested parties following listing. A 
final decision on designation of critical habitat was to have been made 
by May 2, 1992.
    On August 11, 1994, the Sierra Club Legal Defense Fund, Inc. 
(Fund), on behalf of the Orleans Audubon Society and Florida Wildlife 
Federation, gave written notice of their intent to file suit against 
the Department of the Interior for failure to designate critical 
habitat for the Gulf sturgeon within the statutory time limits 
established under the Act. The Fund filed suit (Orleans Audubon Society 
v. Babbitt, Civ. No. 94-3510 (E.D. La)) following a combined meeting 
and teleconference with the Service on October 11, 1994.
    On August 23, 1995, the Services published a notice of decision (60 
FR 43721) on critical habitat designation for the Gulf sturgeon. The 
Services determined that critical habitat designation was not prudent 
based on the lack of additional conservation benefit to the species.
    On November 23, 1995, the above mentioned plaintiffs again gave 
notice of their intent to file suit against the Departments of the 
Interior and Commerce for failing to designate critical habitat for the 
Gulf sturgeon. On January 31, 1996, the Court denied both the Services' 
motion to dismiss the suit and the plaintiffs' motion to find the 
Services in contempt. On October 28, 1997, the Court rejected the 
plaintiffs' request for a Court order requiring the Services to 
designate critical habitat. The plaintiffs' motion for summary judgment 
was granted, with relief restricted to a remand of the matter to the 
agencies for further consideration based on the best scientific 
information available.

Critical Habitat Definition and Requirements

    Critical habitat is defined in section 3(5)(A) of the Act as ``(i) 
the specific areas within the geographic area occupied by a species * * 
* on which are found those physical or biological features (I) 
essential to the conservation of the species, and (II) that may require 
special management considerations or protection; and (ii) specific 
areas outside the geographical area occupied by a species at the time 
it is listed * * * upon determination by the Secretary that such areas 
are essential for the conservation of the species.'' The term 
``conservation,'' as defined in Section 3(3) of the Act, means ``* * * 
to use and the use of all methods and procedures which are necessary to 
bring any endangered or threatened species to the point at which the 
measures provided pursuant to this Act are no longer necessary,'' i.e., 
the species is recovered and can be removed from the list of endangered 
and threatened species. Section 4(a)(3) of the Act requires that 
critical habitat be designated at the time any species is listed as an 
endangered or threatened species, to the extent prudent and 
determinable. If a final regulation listing a species finds that 
critical habitat is not determinable, a critical habitat designation 
must be made within one additional year (within two years of the date 
on which the species was proposed for listing).
    Section 4(b)(2) of the Act requires the Services to consider the 
economic impact of designating any particular area as critical habitat. 
The Services' regulations for listing endangered and threatened species 
and designating critical habitat (50 CFR 424.19) require that, in 
analyzing such impacts, the Services identify any significant 
activities that would either affect an area considered for designation 
as critical habitat or be likely to be affected by the designation, and 
after proposing the designation for such an area, consider the probable 
economic and other impacts of the designation upon proposed or ongoing 
activities. An area may be excluded from critical habitat if it is 
determined that the economic benefits of such exclusion outweigh the 
conservation benefits of including the area in critical habitat. 
Exclusions may not be made if the failure to designate them as critical 
habitat would result in the extinction of the species concerned. This 
standard approximates the jeopardy standard of the Act, but may be less 
stringent because it requires a determination that the exclusion ``* * 
* will result in the extinction * * *'' rather than more probabilistic 
criterion ``* * * likely to jeopardize the continued existence * * *'' 
of section 7(a)(2).
    If no exclusions are made to critical habitat, it should (presuming 
adequate biological and distributional information is available) 
include all areas necessary to recover the species. If areas are 
excluded from critical habitat for economic reasons, final critical 
habitat designation could range from an area just under that required 
for recovery to an area barely sufficient to prevent the species' 
extinction, and insufficient for its recovery. In summary, while the 
Act defines ``conservation'' to mean recovery of the species, section 
4(b)(2) does not require the Services to designate critical habitat 
sufficient for the recovery of the species if economic benefits of 
excluding certain areas outweigh the conservation benefit to the 
species from their inclusion.
    In accordance with the definition of critical habitat provided by 
section 3(5)(A)(i) of the Act, the Services' regulations (50 CFR 
424.12) require the Services to consider the principal biological or 
physical features that are essential to the conservation of the 
species. General requirements of species include, but are not limited 
    (1) Space for individual and population growth, and for normal 
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, rearing of offspring, 
germination, or seed dispersal; and generally
    (5) Habitats that are protected from disturbance or are 
representative of the historic geographical and ecological 
distributions of a species.
    The regulations further require the Services to focus on principal 
biological or physical constituent elements within the defined area 
that are essential to the conservation of the species. Primary 
constituent elements may include, but are not limited to, roost sites, 
nesting grounds, spawning sites, seasonal wetland or dryland, water 
quality or quantity, host species or plant pollinators, geological 
formation, vegetation type, tide, and specific soil types.
    The regulations state that a designation of critical habitat is not 
prudent if either of the two following situations exist:
    (1) The species is threatened by taking or other human activity, 
and identification of critical habitat can be expected to increase the 
degree of such threat to the species, or
    (2) Such designation of critical habitat would not be beneficial to 
the species.
    Potential benefits of critical habitat designation derive from 
section 7(a)(2) of the Act, which requires Federal

[[Page 9969]]

agencies, in consultation with the Service, to ensure that their 
actions are not likely to jeopardize the continued existence of listed 
species or to result in the destruction or adverse modification of 
critical habitat of such species. Implementing regulations (50 CFR 
402.14) require each Federal agency to review its actions at the 
earliest possible time to determine whether any action may affect 
listed species or critical habitat. If a determination is made that a 
Federal action may adversely affect a listed species a formal 
consultation is required. All consultations result in a finding of 
whether or not the proposed action is likely to jeopardize the 
continued existence of the species, and, if critical habitat is 
designated, whether the action is likely to destroy or adversely modify 
critical habitat.
    Critical habitat, by definition, applies only to Federal agency 
actions. 50 CFR 402.02 defines ``jeopardize the continued existence 
of'' as meaning to engage in an action that would reasonably be 
expected, directly or indirectly, to reduce appreciably the likelihood 
of both the survival and recovery of a listed species in the wild by 
reducing the reproduction, numbers, or distribution of that species. 
``Destruction or adverse modification'' is defined as a direct or 
indirect alteration that appreciably diminishes the value of critical 
habitat for both the survival and recovery of a listed species. Such 
alterations include, but are not limited to, alterations adversely 
modifying any of those physical or biological features that were the 
basis for determining the habitat to be critical. Thus, in the section 
7(a)(2) consultation process, the jeopardy analysis focuses on 
potential effects on the species' populations, whereas the destruction 
or adverse modification analysis focuses on habitat value, specifically 
on those constituent elements identified in the critical habitat 
listings in 50 CFR 17.95, 17.96 (FWS), or 226 (NMFS). However, either a 
jeopardy or a destruction or adverse modification biological opinion 
requires the Services to find an appreciable effect on both the 
species' survival and recovery.
    Federal actions satisfying the standard for adverse modification 
are nearly always found to also jeopardize the species concerned, and 
the existence of critical habitat designation does not materially 
affect the outcome of consultation. Biological opinions which conclude 
that a Federal agency action is likely to adversely modify critical 
habitat but is not likely to jeopardize the species for which it is 
designated are extremely rare historically; none have been issued in 
recent years. Such situations might involve a Federal action in 
critical habitat outside of current range of the species, where the 
action would not reduce the current reproduction, distribution, or 
numbers of the species, but would appreciably reduce the value of 
critical habitat for both survival and recovery. For some highly 
endangered species whose survival and recovery in its current range was 
unlikely, and which depended on the expansion of its range and numbers 
into currently unoccupied habitat, the designation of unoccupied 
critical habitat may in certain rare instances provide additional 
protection to that afforded by the jeopardy standard. Since threatened 
species such as the Gulf sturgeon are, by definition, not currently at 
risk of extinction, but are rather anticipated to become so in the 
foreseeable future, unoccupied critical habitat would not be 
immediately required for their survival.
    It should be noted also that regardless of critical habitat 
designation, Federal agencies are required by section 7(a)(1) of the 
Act to utilize their authorities in furtherance of the Act's purposes 
by carrying out conservation (i.e., recovery) activities for listed 
species. For no jeopardy (or no destruction or adverse modification) 
biological opinions, the Services may provide discretionary 
conservation recommendations to the consulting Federal agency to assist 
them in this responsibility. Recovery plans also provide guidance on 
specific tasks that Federal and other agencies can carry out to assist 
in the recovery of listed species.

Ecology of the Gulf Sturgeon

    The Gulf sturgeon is an anadromous species inhabiting the Gulf of 
Mexico and Gulf Coast rivers from Louisiana to Florida. Adults and 
subadults spend eight to nine months each year in rivers where they 
spawn and three to four of the coolest months in estuaries or Gulf 


    In Florida, both adults and subadults begin moving from the Gulf of 
Mexico into the Suwannee and Apalachicola rivers in early spring until 
early May (Carr 1983, Wooley and Crateau 1985, Odenkirk 1989, Clugston 
et al. 1995). River water temperatures at that time range from 16.0 
deg.C to 23.0  deg.C (60.8  deg.F to 75.0  deg.F). Large females 
apparently prefer migrating upstream in shallow water areas, whereas 
deep water areas are preferred during downstream or post spawning 
migrations. This preference does not apply to males (Huff 1975). 
Downstream migration in the Apalachicola River begins in late September 
when water temperatures reach about 23.0  deg.C (75.0  deg.F), and 
extends into November (Wooley and Crateau 1985). During the fall 
migration from fresh to salt water, Gulf sturgeon in the Apalachicola 
River enter the Brothers River, a tributary located about 19.2 
kilometers (km) (12.0 miles (mi)) above the Gulf of Mexico. It is 
believed that the Brothers River is used as a staging area for Gulf 
sturgeon to osmoregulate (adjust to changed salinity) prior to entering 
the Gulf of Mexico. The sturgeon occupy a microhabitat 8.0 to 18.0 m 
(26.2 to 59.0 ft) in depth with a sand and clay substrate covered with 
Asiatic clams (Corbicula fluminea) and detritus (Wooley and Crateau 
1985). The fish remain in the Brothers River for an average of twelve 
days (Wooley and Crateau 1985, Odenkirk 1989). Very little is known 
about the estuarine and neritic (shallow coastal waters) habitat use of 
migrating Gulf sturgeon. Parauka (U.S. Fish and Wildlife Service 1997) 
found that subadult Gulf sturgeon immigrating from the Choctawhatchee 
River into the estuarine waters of Choctawhatchee Bay moved generally 
along the shoreline. Water depths ranged from 2.0 to 7.0 m (6.5 to 23.0 
ft) with a sand and mud substrate.

Freshwater Habitat

    Foster and Clugston (1997) found that telemetered Gulf sturgeon in 
the Suwannee River were frequently located close to springs throughout 
the warmest period, but none were located within a spring or the 
thermal plume emanating from a spring. The substrate of much of the 
Suwannee River is sand and limerock, especially in those areas near 
springs and spring runs. Wooley and Crateau (1985) reported that Gulf 
sturgeon in the Apalachicola River utilized the area immediately 
downstream from Jim Woodruff Lock and Dam (JWLD) from May through 
September. The area occupied consisted of the tailrace and spillway 
basin of JWLD and a large scour hole below the lock. The area consisted 
of sand and gravel substrate with water depths ranging from 6.0 to 12.0 
m (19.7 to 39.4 ft). Telemetry studies conducted on Gulf sturgeon in 
the Choctawhatchee River found that they did not distribute themselves 
uniformly throughout the river and did not occupy the deepest and 
coolest water available (Potak et al. 1995). Fish remained within two 
primary summer holding areas staying outside the main channel where 
water velocities were less than the maximum available. Most fish were 
in water depths of 1.5 to 3.0 m (4.9 to 9.9 ft) and substrates were 
silt or clay. Morrow et

[[Page 9970]]

al. (in press) reported that the lower part of the West Middle River 
(lower Pearl River system) was an important summer habitat for juvenile 
and sub-adult Gulf sturgeon. The habitat is characterized with water 
depths ranging from 9.0 to 19.0 m (29.5 to 62.3 ft) with sluggish flows 
and a hard substrate of sand and gravel.

Estuarine Habitat

    Mason and Clugston (1993) noted that the estuarine seagrass beds 
with mud and sand substrates appear to be important winter habitats for 
Gulf sturgeon where most of the feeding is thought to occur. Clugston 
et al. (1995) reported that the young Gulf sturgeon in the Suwannee 
River, weighing between 0.3 and 2.5 kilograms (kg) (0.7 to 5.5 pounds 
(lb)), remained in the vicinity of the river mouth and estuary during 
the winter and spring. Fox and Hightower (1997) captured adult Gulf 
sturgeon in the early spring in Choctawhatchee Bay prior to their 
migration into the Choctawhatchee River. Fish were collected in 
stationary gill nets set 455.0 m (1,500 ft) from shore at depths of 2.0 
to 4.0 m (6.5 to 13.0 ft). The bay at that site is about 5.5 km (3.4 
mi) wide and with depths up to 6.7 m (22.0 ft). Parauka (U.S. Fish and 
Wildlife Service 1997) collected 6 subadult Gulf sturgeon in the 
Choctawhatchee River, equipped them with acoustic tags, and monitored 
their movement in the estuary during the winter. Five of six fish 
remained in the estuary the entire winter occupying nearshore habitats, 
1.2 to 4.6 m (4 to 15 ft) in depth with a sand and mud substrate.

Food Habits

    Mason and Clugston (1993) reported that in the spring, immigrating 
subadult and adult Gulf sturgeon collected from the mouth of the 
Suwannee River contained gammarid, haustoriid, and other maphipods, 
polychaete and oligochaete annelids, lancelets, and brachiopods. 
However, once in fresh water, these Gulf sturgeon did not eat as 
evidenced by the presence of only a greenish-tinged mucus in their guts 
from June through October. The stomach contents of a 79.5 kg (175 lb) 
Gulf sturgeon collected in Choctawhatchee Bay during the winter 
contained adult ghost and commensal shrimp (R. Head, Gulf Coast 
Research Laboratory, personal communication 1997). Clugston et al. 
(1995) concluded that Gulf sturgeon appear to gain weight only during 
the winter and spring while in marine or estuarine waters and lose 
weight during the eight to nine month period while in fresh water. Carr 
(1983) reported that marked Gulf sturgeon from the Suwannee River 
gained up to 30 percent of body weight in one year but showed little or 
no growth when recaptured during the same season. Wooley and Crateau 
(1985) noted that Gulf sturgeon 80.0 to 114.0 centimeters (cm) (31.5 to 
44.9 inches (in)) long that were captured and recaptured in the 
Apalachicola River during the summer period exhibited weight losses of 
4 to 15 percent or 0.5 to 2.3 kg (1.1 to 5.1 lb).

River-Specific Fidelity

    The results of tagging studies suggest that Gulf sturgeon exhibit a 
high degree of river fidelity. From 1981 to 1993, 4,100 fish were 
tagged in the Apalachicola and Suwannee rivers, with 860 fish 
recaptured in the river of initial collection and only 8 sub-adults 
exhibiting inter-river movement (Wooley and Crateau 1985, U.S. Fish and 
Wildlife Service and Gulf States Marine Fisheries Commission 1995, Carr 
et al. 1996, Foster and Clugston 1997). Foster and Clugston (1997) 
noted that telemetered Gulf sturgeon in the Suwannee River returned to 
the same areas as the previous summer suggesting that chemical cuing 
may influence distribution. Wooley and Crateau (1985) indicate that the 
results of tagging Gulf sturgeon in the Apalachicola River would 
suggest the fish are genetically or behaviorally imprinted to the 
chemosensory environment of their home rivers. Stabile et al. (1996) 
analyzed Gulf sturgeon populations from eight drainages along the Gulf 
of Mexico for genetic diversity. He noted significant differences among 
Gulf sturgeon stocks and suggested that they displayed region-specific 
affinities and may exhibit river-specific fidelity. Stabile et al. 
(1996) identified five regional or river-specific stocks (from west to 
east)--(1) Lake Ponchartrain and Pearl River, (2) Pascagoula River, (3) 
Escambia and Yellow rivers, (4) Choctawhatchee River, and (5) 
Apalachicola, Ochlockonee, and Suwannee rivers.


    Gulf sturgeon are long-lived, reaching at least 42 years in age 
(Huff 1975). Age at sexual maturity for females ranges from 8 to 17 
years, and for males from 7 to 21 years (Huff 1975). Fertilized Gulf 
sturgeon eggs were collected at 2 upriver locations on the Suwannee 
River (Marchent and Shutters 1996) and 6 upriver sites on the Pea and 
Choctawhatchee rivers (Fox 1997). Habitat at the egg collection sites 
consisted of limestone bluffs and outcroppings, cobble, limestone 
gravel and sand with water depths ranging from 1.4 to 7.9 m (4.5 to 
26.0 ft). Water temperatures ranged from 18.3  deg.C to 22.0  deg.C 
(65.0  deg.F to 71.6  deg.F). Chapman et al. (1993) reported that three 
mature Gulf sturgeon had 458,080; 274,680; and 475,000 eggs and were 
estimated to have an average fecundity of 20,652 eggs/kg (9,366 eggs/


    Population estimates for Gulf sturgeon in the Apalachicola River 
have been conducted from 1984 to 1993. During that period, estimates of 
fish exceeding 45.0 cm (17.7 in) in length ranged from 96 to 131 fish 
with a mean of 115 (F. Parauka, FWS, personal communication; U.S. Fish 
and Wildlife Service and Gulf States Marine Fisheries Commission 1995). 
In the Suwannee River, a mark/recapture study implemented from 1986 to 
1994 estimated a population of 1,504 to 3,066 for Gulf sturgeon 
weighing between 3.0 and 81.0 kg (6.6 to 178.2 lb) (Carr et al. 1996). 
Morrow et al. (in press) estimated that the summer population of Gulf 
sturgeon in the West Middle Pearl River, 459 to 1143 mm (18 to 46 in) 
in length, ranged from 67 to 124 fish.

Habitat Needs

    The Gulf sturgeon requires nearshore (bays and estuaries) and 
offshore (Gulf of Mexico) feeding areas, and freshwater rivers for 
spawning and resting habitat. Specific habitat needs of the Gulf 
sturgeon, in the context of the constituent elements discussed above, 
    1. Migration corridors which support subspecies' distribution 
throughout its primary range. Primary range for the Gulf sturgeon in 
freshwater extends from the Mississippi River to the Suwannee River in 
Florida (Wooley and Crateau 1985). A migration corridor is a Gulf Coast 
river drainage within the primary range through which sturgeon pass 
between marine and estuarine environments to freshwater spawning and 
resting sites. Records of Gulf sturgeon through sightings, incidental 
captures, and tagging studies have been made over the last ten years 
from most major drainages and a number of smaller river systems 
(Reynolds 1993, U.S. Fish and Wildlife Service and Gulf States Marine 
Fisheries Commission 1995). Tagging studies in the Apalachicola and 
Suwannee rivers demonstrated the high probability of recapturing fish 
in the same river where they were first tagged (Wooley and Crateau 
1985, Foster and Clugston 1997). A small number of sub-adult fish 
exhibited inter-river movement; however, the data obtained from capture 
and recapture studies suggest that Gulf sturgeon have a high degree of 

[[Page 9971]]

fidelity. Stabile et al. (1996) noted significant genetic differences 
among Gulf sturgeon stocks and suggested that they displayed region-
specific affinities and may exhibit river-specific fidelity which 
further defines an essential migratory corridor. The significance of 
this study to critical habitat is discussed in the section on proposed 
    2. Silt-free, consolidated bottom substrate composed of rock, 
gravel or hard sand. This material can be the predominant benthic 
substrate in some drainages, while in others it can be more patchily 
distributed (U.S. Fish and Wildlife Service and Gulf States Marine 
Fisheries Commission 1995). This feature is often associated with 
springs, geologic outcroppings, and deep holes. Adult, sub-adult, and 
juvenile Gulf sturgeon frequent such sites and these areas are thought 
to be important for spawning and resting (Wooley and Crateau 1985, 
Odenkirk 1989, Carr et al. 1996, Marchent and Shutters 1996, Foster and 
Clugston 1997). Telemetry and tagging studies further suggest that 
individuals return to the same areas of the river inhabited the 
previous summer (Foster 1993, Carr et al. 1996, Foster and Clugston 
1997, U.S. Fish and Wildlife Service 1989, 1990, 1991, 1992, 1993).
    3. Adequate water quantity and quality for normal behavior in both 
fresh and brackish environments. Normal behavior includes, but is not 
limited to, migration of adult, subadult, and juvenile sturgeon; local 
movement and feeding by larval and juvenile stages; and reproduction. 
Natural surface and groundwater discharges influence a river's 
characteristic fluctuations in volume, depth, and velocity (Torak et 
al. 1993, Leitman et al. 1993). Migrating sturgeon and planktonic 
larvae are adapted to conditions in their natal rivers which affect 
distance traveled and survival. These demographics may be influenced by 
changes in the water quantity parameters (U.S. Fish and Wildlife 
Service and Gulf States Marine Fisheries Commission 1995).
    Temperature, sediment load, and chemical constituents are important 
water quality features. Seasonal changes in water temperature trigger 
sturgeon migration into and out of rivers (Wooley and Crateau 1985). 
Cooler waters associated with deep holes, springs and spring runs 
appear to be important for spawning (Marchant and Shutters 1996, Smith 
and Clugston 1997) and also as refugia from ambient water temperatures 
during summer and fall (Carr et al. 1996). Sturgeon access to these 
springs, spring runs, and deep holes may depend upon the maintenance of 
stream bed elevation through the natural removal and deposition of 
sediment (U.S. Army Corps of Engineers 1986). Changes in flow dynamics 
resulting from surface and groundwater withdrawals for drinking and 
irrigation (Torak et al. 1993, Leitman et al. 1993), and excessive 
sedimentation resulting from riverbed elevation changes due to dams and 
other navigation activities (U.S. Army Corps of Engineers 1986) have 
impacted these sites.
    Undesirable chemicals contaminating river water may enter sturgeon 
through contact with water, sediment, or food sources. Bateman and Brim 
(1994, 1995) found heavy metals, other inorganics, organochlorine 
compounds, and polycyclic aromatic hydrocarbons in juvenile and adult 
Gulf sturgeon from Florida. A variety of toxic effects to fish from 
these contaminants have been demonstrated (Mayer and Mehrle 1977, 
Armstrong 1979, Johnson and Finley 1980, White et al. 1983, Fox 1992).

Historical and Current Threats to the Species

    Identified threats for the Gulf sturgeon include historic 
overexploitation, incidental take, habitat loss and degradation, 
contaminants, and potential hybridization with a non-native species, 
the white sturgeon (Acipenser transmontanus), used in aquaculture.
    The Gulf sturgeon historically was considered important because its 
eggs and smoked flesh were valued foods, its oil was used in paints, 
and the swim bladder yielded isinglass, a gelatin used in food products 
and glues (Smith and Clugston 1994). The resulting demand produced an 
intense and directed fishing industry. Available landing records 
indicate that the principal commercial, recreational, and subsistence 
fisheries were in west Florida, especially in the Apalachicola and 
Suwannee rivers (Burgess 1963, Huff 1975, Swift et al. 1977, Futch 
1984, Barkuloo 1988). Directed commercial harvest of Gulf sturgeon in 
other Gulf states was minor or incidental. Most commercial fishing 
occurred from the late 19th century until the 1970's, with peak catches 
in Florida recorded around 1900. Harvest thereafter declined swiftly 
and averaged around three percent of peak until the fishery collapsed 
by the late 1970's. From 1972 to 1990, State regulatory agencies in 
Alabama, Mississippi, Florida, and Louisiana enacted laws prohibiting 
any take of Gulf sturgeon within their jurisdictional waters.
    The historic decline of Gulf sturgeon populations (Barkuloo 1988) 
begun by over-exploitation was later exacerbated by habitat 
destruction, degradation, and inaccessibility. Water control 
structures, high- and low-head dams, and sills within a number of river 
drainages throughout its range prevent or severely restrict sturgeon 
access to historic migration routes and spawning areas (Boschung 1976, 
Murawski and Pacheco 1977, Wooley and Crateau 1985, McDowell 1988). 
Dredging, spoil disposal, and other navigation maintenance may have 
adversely affected Gulf sturgeon habitats through lowering of river 
elevations, elimination of deep holes, and altering of rock substrates 
(Carr 1983, Wooley and Crateau 1985). Cool waters emanating from 
springs are believed to be important thermal refugia for sturgeon and 
other anadromous fish during warm weather (see below).
    S. Carr (pers. comm.) believed that cool water habitats which 
appear to serve as thermal refugia during summer months may be impacted 
by reduction in groundwater flows. Leitman et al. (1993) indicated that 
the major spring-fed flow component of Georgia's Flint River, a major 
flow contributor to the Apalachicola River during low-flow periods, has 
been reduced since the early 1970's from groundwater and surface water 
irrigation withdrawals. More specifically, increased groundwater 
withdrawal for irrigation in southwest Georgia may result in a 30 
percent reduction of discharge to streams (Hayes et al. 1983). These 
actions, in conjunction with drought, may have caused the observed 
reduction and cessation of water flow from several springs and spring 
runs in the upper Apalachicola River. Reduction of cool water flows or 
their complete loss during critical summer periods could subject 
sturgeon to increased environmental stress.
    Agricultural and industrial contaminants also may be affecting fish 
populations. DDT and its DDD/DDE metabolites were detected in Gulf 
sturgeon samples collected from Florida Gulf river drainages between 
1985 to 1991 (Bateman and Brim 1994). A second organochlorine 
insecticide, toxaphene, was detected in fish from the Apalachicola 
River during the same study. General organochlorine effects on fish 
include reproductive failure, reduced survival of young, and 
physiological alterations affecting their ability to withstand stress 
(White et al. 1983). DDT compounds are also known to be endocrine 
disrupters (Fox 1992). Toxaphene has been shown to impair reproduction, 
reduce growth in adults and juveniles, and alter collagen formation in 
fry, resulting in ``broken back syndrome'' (Mayer and Mehrle

[[Page 9972]]

1977). Bateman and Brim (1994, 1995) also detected heavy metals 
including arsenic, cadmium, lead, mercury, and polycyclic aromatic 
hydrocarbons, the latter at levels which could adversely affect 
development and survival of eggs and larval and juvenile fish.
    Accidental or intentional introductions of cultured stocks and non-
endemic species, such as the white sturgeon (Acipenser transmontanus), 
could also potentially harm wild Gulf sturgeon stocks. In addition to 
these anthropogenic impacts, the life history of Gulf sturgeon 
complicates recovery efforts. Breeding populations take years to 
establish due to their advanced age at sexual maturity. The subspecies 
appears to be a home stream spawner, with little if any natural 
repopulation by migrants from other rivers.

Application of Critical Habitat Designation to Threats

    Take of Gulf sturgeon is prohibited throughout its range by section 
9 of the Act and by State laws. Critical habitat designation would 
provide no benefit to the application of these prohibitions.
    Habitat loss and degradation and contaminant threats are directly 
related to physical and biological features essential to the 
conservation of the Gulf sturgeon. Additional protection from critical 
habitat designation would apply in the case of Federal actions that 
were likely to destroy or adversely modify critical habitat yet not 
jeopardize the continued existence of the species. The Services believe 
this scenario is highly unlikely. The U.S. Army Corps of Engineers' 
navigation maintenance activities, dam and water control construction 
and operations, and permitting program have the potential to affect all 
of the constituent elements discussed above--(1) migration corridors 
could be affected by dams and possibly reduced water flow, (2) bottom 
substrate could be affected by dredging or deposition of dredged 
materials, and (3) water quality could be affected by increased 
turbidity or changed temperature, and water quantity could be reduced. 
In order to trigger an adverse modification biological opinion without 
jeopardy, such effects would have to appreciably reduce the value of 
designated critical habitat for both the survival and recovery of the 
Gulf sturgeon without reducing its reproduction, distribution, or 
numbers. Most of the Corps' activities will take place in occupied 
habitat and a significant reduction in habitat value within occupied 
habitat of the Gulf sturgeon will inevitably reduce its reproduction, 
distribution, or numbers, thus providing the protection of the jeopardy 
prohibition. Unoccupied upstream habitat will still be subject to 
consultation, regardless of critical habitat designation, if a proposed 
project would affect downstream occupied habitat (e.g., changed water 
flows). An example would be the Flint and Chattahoochee rivers in 
Georgia, where the disappearance of Gulf sturgeon occurred following 
the construction of Jim Woodruff Dam and its locks in Florida in 1956.
    On July 25, 1996, the FWS provided the Corps with a biological 
opinion on the proposed West Pearl River Navigation Project in 
Louisiana and Mississippi. The project involved dredging three river 
segments. The Gulf sturgeon was one of the federally listed species 
considered in the opinion. Regardless of the lack of designated 
critical habitat, the FWS considered features of the Gulf sturgeon's 
habitat (resuspension of sediments, spread of contaminants, turbidity 
increases from increased navigation, geomorphic changes) in reaching 
the decision that the project was not likely to jeopardize the 
continued existence of the Gulf sturgeon. The no jeopardy finding was 
based on two factors--(1) existing stable populations of the Gulf 
sturgeon are found in off-project portions of the Lower Pearl River 
Basin; and (2) The proposed project activities were localized and 
temporary in nature.
    This biological opinion demonstrates that habitat features are an 
essential part of the analysis for any biological opinion under the 
jeopardy standard; that is, any analysis of the effects on 
reproduction, distribution, or numbers of the Gulf sturgeon would have 
to consider the effects of changes to the fish's habitat. Critical 
habitat designation would not have added additional protection--it 
would not have been possible to arrive at a destruction of adverse 
modification biological opinion because habitat value for both survival 
and recovery of the species was not appreciably reduced.
    Permitting under the Environmental Protection Agency's (EPA) 
National Pollution Discharge Elimination System (NPDES), water quality 
standards, and pesticide registration have the potential to affect 
water quality for the Gulf sturgeon. Since the Gulf sturgeon inhabits 
larger channel areas, the effects of any point discharge into its 
habitat would likely be minimized by dilution, and the States of 
Louisiana, Mississippi, Alabama, and Florida set water quality 
standards that are believed to be protective of aquatic life. The 
Service believes that if current Federal water quality standards under 
the CWA are maintained, there will be no need to modify the State's 
water quality standards to protect habitat for the Gulf sturgeon. 
Pesticide registration would have to be evaluated on a case-by-case 
basis. The Services believe that, for these activities to reach the 
survival and recovery criteria, reproduction, distribution, or numbers 
of the Gulf sturgeon would be affected and that potential threats can 
be effectively addressed under the jeopardy standard.

Relation of Critical Habitat Designation to Recovery/Management 

    Section 4(f)(1) of the Act requires the Services to develop and 
implement recovery plans for endangered and threatened species, unless 
such a plan would not promote the conservation of the species.
    The Services classify recovery tasks according to three priorities:
    (1) Priority 1 tasks are actions that must be taken to prevent 
extinction or to prevent the species from declining irreversibly in the 
foreseeable future.
    (2) Priority 2 tasks are actions that must be taken to prevent a 
significant decline in species population, habitat quality, or some 
other significant negative impact short of extinction.
    (3) Priority 3 tasks are all other actions necessary to meet the 
recovery objectives.
    The section 7 consultation process is closely linked with recovery 
through both section 7(a)(1) and 7(a)(2). Because priority 1 and 2 
tasks are closely related to a species' survival and recovery, they 
provide guidance on Federal activities that could result in jeopardy or 
destruction or adverse modification biological opinions. Priority 3 
tasks provide guidance on activities that could further the 
conservation of the species, and which would be included by the 
Services as conservation recommendations, pursuant to 50 CFR 402.14(j) 
in biological opinions.
    The Recovery/Management Plan (Plan) for the Gulf sturgeon (U.S. 
Fish and Wildlife Service and Gulf States Marine Fisheries Commission, 
1995) was written by a recovery/management team including 
representatives from the affected States, the Services, the U.S. Army 
Corps of Engineers, the Caribbean Conservation Corporation, the 
University of Florida, and a commercial fisherman. The Plan was 
approved by the Services and the Gulf States Marine Fisheries 
Commission in September 1995. The basic objectives of the Plan are:
    (1) In the short term, prevent further reductions of wild Gulf 
sturgeon populations throughout the range.
    (2) For recovery, establish population levels that would allow 
delisting of the

[[Page 9973]]

Gulf sturgeon by management units based on river drainages.
    (3) Establish, following delisting, a self-sustaining population 
that could support fishing pressure within management units.
    When a recovery plan has been prepared for a species it 
incorporates the management actions necessary for the conservation of 
the species. If the recovery tasks involve Federal actions, they are 
subject to consultation under section 7 of the Act, either between the 
implementing agency and the Services or, if carried out by FWS or NMFS, 
within the agency.
    Critical habitat designation is not included as a task in the Plan. 
However, since potential benefits of critical habitat designation are 
linked to recovery tasks through the section 7 consultation process, 
the Services have analyzed priority 1 and 2 recovery actions (those 
which are required for the survival of the Gulf sturgeon) for potential 
added protection if critical habitat were designated. The analysis is 
based on the assumption that loss of habitat value to the point of 
affecting survival in occupied habitat will, by definition, reduce 
reproduction, distribution, or numbers of the Gulf sturgeon. Critical 
habitat designation, therefore, will not add protection in occupied 
habitat because the definition of destruction or adverse modification 
and that of jeopardy both require an effect on survival (and recovery) 
of the species. The high priority tasks are summarized as follows:

                                                          Habitat value affected, not                           
        Priority                      Task                 reproduction, numbers, or         Net benefit from   
                                                                 distribution               critical habitat?   
1.......................  1.3.1  Develop and           No                                No.                    
                           implement monitoring                                                                 
1.......................  2.5.3  Regulate accidental   No                                No.                    
                           and intentional                                                                      
1.......................  2.1.2  Reduce or eliminate   No                                No.                    
                           incidental mortality.                                                                
1.......................  2.4.5  Restore natural       No                                No.                    
                           river habitats.                                                                      
1.......................  2.3.1  Protect habitat with  Potentially                       No.                    
                           existing laws or                                                                     
                           additional laws or                                                                   
2.......................  2.1.1  Effectively enforce   No                                No.                    
                           take prohibitions.                                                                   
2.......................  1.1.1  Locate important      No                                No.                    
2.......................  1.1.2  Characterize          No                                No.                    
                           essential habitat areas.                                                             
2.......................  1.2  Conduct life history    No                                No.                    
2.......................  2.2.1  Identify              No                                No.                    
2.......................  2.2.2  Eliminate             Potentially                       No.                    
2.......................  2.4.6  Coordinate            No                                No.                    
                           consistent water projects.                                                           
2.......................  2.4.1  Identify dam/lock     Yes                               No.                    
                           sites for restoration.                                                               
2.......................  2.4.4  Minimize effects of   Potentially                       No.                    
                           navigation projects.                                                                 
2.......................  4.3  Implement projects to   No                                No.                    
                           achieve recovery plan                                                                
2.......................  4.2  Seek funding for        No                                No.                    
                           recovery activities.                                                                 
2.......................  2.2.4  Eliminate impacts to  Potentially                       No.                    
                           water quality and quantity.                                                          
2.......................  2.2.5  Assess effects of     No                                No.                    
                           groundwater pumping on                                                               
                           riverine habitat.                                                                    

    Tasks 1.3.1, 2.5.3, 2.1.2, and 2.1.1 are not habitat related and 
would not benefit from critical habitat designation. Tasks 1.1.1, 
1.1.2, 1.2, 2.2.1, 2.4.6, 2.4.1, 4.3, 4.2, and 2.2.5 are informational 
or procedural and are, therefore, also independent of potential 
critical habitat benefits.
    Tasks 2.4.5 and 2.3.1 address both occupied and unoccupied habitat; 
however, there is no priority 1 or 2 task in the plan requiring 
additional authority for protecting unoccupied habitat. Protection of 
unoccupied habitat is, therefore, essential for full recovery, but not 
for survival of the Gulf sturgeon.
    Under tasks 2.2.2, 2.2.4 and 2.4.4 navigation and water quality and 
quantity projects in unoccupied habitat will not affect survival of the 
Gulf sturgeon unless they indirectly affect its reproduction, 
distribution, or numbers in occupied areas. The criterion requiring 
harm to both ``survival and recovery'' is not met by projects affecting 
only unoccupied habitat.
    Most of the Plan tasks involve activities that affect the 
reproduction, numbers, and distribution of the Gulf sturgeon, and, 
therefore, for which critical habitat designation would afford no 
additional protection. Tasks that would potentially receive additional 
protection from the section 7 prohibition on destruction or adverse 
modification of critical habitat are those that involve unoccupied 
habitat, where habitat might be reduced in value without affecting 
reproduction, numbers, or distribution of the Gulf sturgeon. However, 
habitat related tasks in the Plan involving unoccupied habitat do not 
meet the ``survival and recovery'' criterion in the definition of 
destruction or adverse modification. In summary, no high priority 
recovery plan actions (those which are designed to ensure survival of 
the Gulf sturgeon) have been identified that would benefit from 
critical habitat designation. Known or anticipated Federal agency 
actions that would appreciably diminish the value of critical habitat 
of the Gulf sturgeon (thereby invoking the destruction or adverse 
modification standard) would also reduce appreciably the likelihood of 
both the survival and recovery of the species by reducing its 
reproduction, numbers, or distribution (thus triggering the jeopardy 
standard). Both definitions require impairment of survival and recovery 
and are functionally equivalent.
    Based on the above discussion, the Services have determined that 
the lack of additional conservation benefit from critical habitat 
designation for this species makes such designation not prudent.

References Cited

    A complete list of all references cited herein is available upon 
request from the Jacksonville Field Office (see ADDRESSES section).
    Authors: The primary authors of this document are Dr. Michael M. 
Bentzien and Mr. Francis M. Parauka, FWS; and Ms. Colleen Coogan, NMFS 
(see ADDRESSES section).

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

[[Page 9974]]

    Dated: February 20, 1998.
Jamie Rappaport Clark,
Director, Fish and Wildlife Service.

    Dated: February 24, 1998.
David L. Evans,
Deputy Assistant Administrator for Fisheries, National Marine Fisheries 
[FR Doc. 98-5193 Filed 2-26-98; 8:45 am]