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

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 226

DEPARTMENT OF THE INTERIOR

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,

Interior.

ACTION: Notice of decision on critical habitat designation.

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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

sturgeon.

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

1998.

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.

SUPPLEMENTARY INFORMATION:

Background

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

to:

(1) Space for individual and population growth, and for normal

behavior;

(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

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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

waters.

Migration

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.

Reproduction

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/

lb).

Population

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,

include:

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

river

[[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

designation.

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

Plan

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

techniques.

1....................... 2.5.3 Regulate accidental No No.

and intentional

introductions.

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

incentives.

2....................... 2.1.1 Effectively enforce No No.

take prohibitions.

2....................... 1.1.1 Locate important No No.

habitats.

2....................... 1.1.2 Characterize No No.

essential habitat areas.

2....................... 1.2 Conduct life history No No.

studies.

2....................... 2.2.1 Identify No No.

contaminants.

2....................... 2.2.2 Eliminate Potentially No.

contaminants.

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

objectives.

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

Service.

[FR Doc. 98-5193 Filed 2-26-98; 8:45 am]

BILLING CODE 4310-55-P