Migratory Bird Permits; Proposed Depredation Order for the Double-Crested Cormorant

Part III

Department of the Interior

_______________________________________________________________________

Fish and Wildlife Service

_______________________________________________________________________

50 CFR Part 21

Migratory Bird Permits; Proposed Depredation Order for the Double-

Crested Cormorant; Proposed Rule

Proposed Rules

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 21

RIN 1018-AE11

Migratory Bird Permits; Proposed Depredation Order for the

Double-Crested Cormorant

Agency: Fish and Wildlife Service, Interior.

Action: Proposed rule.

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SUMMARY: The U.S. Fish and Wildlife Service (hereinafter Service)

proposes to implement a depredation order for the double-crested

cormorant. In those States in which double-crested cormorants have been

shown to be seriously injurious to commercial freshwater aquaculture,

and when found committing or about to commit depredations upon

aquaculture stock, persons engaged in the production of aquaculture

commodity stocks would be allowed, without a Federal permit, to take or

cause to be taken such double-crested cormorants as might be necessary

to protect aquaculture stocks.

DATES: Comments must be submitted on or before August 22, 1997.

ADDRESSES: Comments may be mailed to Chief, Office of Migratory Bird

Management (MBMO), U.S. Fish and Wildlife Service, Department of the

Interior, ms 634--ARLSQ, 1849 C Street, NW, Washington, D.C. 20240.

Comments will be available for public inspection during normal business

hours in room 634, Arlington Square Building, 4401 N. Fairfax Drive,

Arlington, Virginia.

FOR FURTHER INFORMATION CONTACT: Paul R. Schmidt, Chief, MBMO, U.S.

Fish and Wildlife Service, (703) 358-1714.

SUPPLEMENTARY INFORMATION:

Background

rtment of the

Interior, ms 634--ARLSQ, 1849 C Street, NW, Washington, D.C. 20240.

Comments will be available for public inspection during normal business

hours in room 634, Arlington Square Building, 4401 N. Fairfax Drive,

Arlington, Virginia.

FOR FURTHER INFORMATION CONTACT: Paul R. Schmidt, Chief, MBMO, U.S.

Fish and Wildlife Service, (703) 358-1714.

SUPPLEMENTARY INFORMATION:

Background

Double-crested cormorant populations are at an all-time high in the

modern era, and commercial aquaculturists (especially catfish farmers)

in many parts of the country are experiencing economic losses due to

cormorant depredation. Three avenues currently are available to

aquaculturists for dealing with cormorant depredation problems: (1)

birds can be harassed (with shotgun blasts, fire crackers, propane

cannons, or other scare devices) without a Federal permit; (2) ponds

can be fitted with physical barriers (or exclusionary devices) such as

wire or mesh netting that prevent birds from landing; and (3) private

aquaculturists and State-operated fish hatcheries can apply to the

Service for a permit to kill cormorants.

The Service is the Federal agency with the primary responsibility

for managing migratory birds. The Service's authority is based on the

Migratory Bird Treaty Act (MBTA) (16 U.S.C. 703-711), which implements

conventions with Great Britain (for Canada), the United Mexican States

(=Mexico), Japan, and the Soviet Union (=Russia). The double-crested

cormorant is afforded Federal protection by the 1972 amendment to the

Convention for the Protection of Migratory Birds and Game Animals,

February 7, 1936, United States--Mexico, as amended, 50 Stat. 1311,

T.S. No. 912, as well as, the Convention Between the United States of

America and the Union of Soviet Socialist Republics [=Russia]

Concerning the Conservation of Migratory Birds and Their Environment,

November 26, 1976, 92 Stat. 3110, T.I.A.S. 9073 (16 U.S.C. 703, 712)

for the Protection of Migratory Birds and Game Animals,

February 7, 1936, United States--Mexico, as amended, 50 Stat. 1311,

T.S. No. 912, as well as, the Convention Between the United States of

America and the Union of Soviet Socialist Republics [=Russia]

Concerning the Conservation of Migratory Birds and Their Environment,

November 26, 1976, 92 Stat. 3110, T.I.A.S. 9073 (16 U.S.C. 703, 712).

The take of double-crested cormorants is strictly prohibited except as

may be permitted under regulations implementing the MBTA. In addition

to, Federal statutes, the double-crested cormorant may also be

protected by State regulations.

Regulations governing the issuance of permits for migratory birds

are authorized by the MBTA and subsequent regulations (Title 50, Code

of Federal Regulations, Parts 13 and 21). Regulations in Subpart D of

Part 21 deal specifically with the control of depredating birds.

Section 21.41 outlines procedures for issuing permits. Sections 21.43

through 21.46 deal with special depredation orders for specific species

of migratory birds to address particular problems in specific

geographical areas, establishing a precedent for species and geographic

treatments in the permitting process. Service policies for issuing

depredation permits for aquaculture were described by Trapp et al.

(1995).

Federal responsibility for the management of injurious wildlife,

including migratory birds, lies with the Animal Damage Control (ADC)

program of the U.S. Department of Agriculture's Animal and Plant Health

Inspection Service. The primary authority for ADC activities is the

Animal Damage Control Act of 1931, as amended, 46 Stat. 1468 (7 U.S.C.

426-426c). Animal Damage Control activities are conducted at the

request of, and in cooperation with, other Federal, State, and local

agencies; private organizations; and individuals. Management

responsibilities of ADC in the cormorant-aquaculture conflict were

reviewed by Acord (1995).

Commercial Aquaculture Industry

he

Animal Damage Control Act of 1931, as amended, 46 Stat. 1468 (7 U.S.C.

426-426c). Animal Damage Control activities are conducted at the

request of, and in cooperation with, other Federal, State, and local

agencies; private organizations; and individuals. Management

responsibilities of ADC in the cormorant-aquaculture conflict were

reviewed by Acord (1995).

Commercial Aquaculture Industry

Aquaculture, the cultivation of finfish and invertebrates in

captivity, has grown exponentially in the past several decades (Price

and Nickum 1995). The five principal aquaculture fish species in the

United States are catfish, trout, salmon, tilapia, and hybrid striped

bass. There are also two categories of non-food fish: baitfish and

ornamental fish (U.S. Department of Agriculture 1995). While each of

these industries has its own unique set of bird depredation problems,

they all share a basic concern for developing and implementing the best

methods for protecting fish stocks from predation.

The market for channel catfish (Ictalurus punctatus) is the largest

segment of the aquaculture industry, and the one which is perhaps most

susceptible to predation by cormorants. The catfish accounts for about

one-half of the value of aquaculture in the United States.

The number of catfish farms in the United States increased 44

percent between 1982 and 1990 (from 1,494 to 2,155). Most of this

increase occurred between 1982 and 1987. Growth was fairly steady

throughout the 1980s, with production leveling off in the past few

years. Production was estimated at 224,875 metric tons (247,933 short

tons, or 496 million pounds, or 225 million kilograms) worth $353

million in 1993 and is expected to expand 5-7 percent annually due to

increasing sales prices.

Mississippi is the center of catfish production, producing 75-80

percent of the United States output. Alabama, Arkansas, and Louisiana

are also major producers

ew

years. Production was estimated at 224,875 metric tons (247,933 short

tons, or 496 million pounds, or 225 million kilograms) worth $353

million in 1993 and is expected to expand 5-7 percent annually due to

increasing sales prices.

Mississippi is the center of catfish production, producing 75-80

percent of the United States output. Alabama, Arkansas, and Louisiana

are also major producers. California, Florida, Illinois, Kentucky,

Missouri, North Carolina, Oklahoma, South Carolina, Texas, and Virginia

also produce catfish and all have, or will have, problems with fish-

eating birds. In the four principal catfish-producing States, the

number of farms increased 67 percent between 1982 and 1992 (from 794 to

1,193); increases in individual States were 24 percent in Alabama (327-

405), 40 percent in Mississippi (316-442), 67 percent in Arkansas (115-

191), and 330 percent in Louisiana (36-155).

The more than 64,300 hectares (158,840 acres) of catfish ponds in

the United States in 1995 represented a 2.3-fold increase from about

28,300 hectares (69,900 acres) in production in the 1970s. The four

principal catfish-producing States accounted for 93 percent of the

total area, with Mississippi alone accounting for about 60 percent.

Catfish ponds range in size from 4-14 hectares (10-35 acres) each, with

a mean size of 5 hectares (12

acres). Farms with 100 hectares (247 acres) in production are not

uncommon, and many are more than 400 hectares (990 acres). In the Delta

region of Mississippi, catfish farms average about 100 hectares (247

acres) of ponds, with a typical rectangular pond size of 8 hectares (20

acres); ponds are shallow, ranging from 1-2 meters (3.3-6.6 feet) deep.

The large size of the ponds makes them highly visible to fish-eating

birds from the air, and the high stocking levels (from 5,000 to more

than 150,000 fish/hectare [or 2,000 to more than 60,700 fish/acre],

Glahn and Stickley 1995) make them especially attractive to cormorants

ypical rectangular pond size of 8 hectares (20

acres); ponds are shallow, ranging from 1-2 meters (3.3-6.6 feet) deep.

The large size of the ponds makes them highly visible to fish-eating

birds from the air, and the high stocking levels (from 5,000 to more

than 150,000 fish/hectare [or 2,000 to more than 60,700 fish/acre],

Glahn and Stickley 1995) make them especially attractive to cormorants.

The catfish industry's practice of using large ponds developed in the

early 1970s when cormorant numbers were low.

The physical dimensions of the ponds are the secret to the catfish

farmers' success (as well as the source of today's predation problem).

The most efficient production ponds are circular, but they can not be

harvested as easily. So, the ponds are generally rectangular and can be

as wide as 80-95 meters (262-312 feet). At harvest time, crews drag 100

meter (325 foot) wide seine nets strung between tractors on both sides

of the rectangular ponds along the length of each pond. Undersize fish

slip through the mesh and are harvested the next year. Because catfish

farmers stock more than one year class of fish in a pond, it is not

possible to drain the ponds and to reconfigure them to a size and shape

that can be covered easily with bird-excluding nets. Also, the levees

between the ponds are not wide enough to install extensive net

structures and yet leave room for tractors to maneuver. Thus, several

economic factors (e.g., low profit margin, the cost to modify the

ponds, and a heavy investment in current harvest technologies) combine

to preclude major changes in pond shape and size at the present time.

Population Status of the Double-crested Cormorant

vees

between the ponds are not wide enough to install extensive net

structures and yet leave room for tractors to maneuver. Thus, several

economic factors (e.g., low profit margin, the cost to modify the

ponds, and a heavy investment in current harvest technologies) combine

to preclude major changes in pond shape and size at the present time.

Population Status of the Double-crested Cormorant

The size of the North American breeding population of the double-

crested cormorant was recently estimated at about 360,000 pairs (Hatch

1995). Using values derived from the published literature of 1-4

nonbreeding birds for each breeding pair yields an estimated total

population of about 1-2 million birds (Hatch 1995).

The double-crested cormorant breeds widely throughout much of

coastal and interior North America. As of 1992, it had been found

breeding in 40 of the 50 United States, all 10 Canadian provinces, and

in Mexico, Cuba, and the Bahamas (Hatch 1995). However, it is not

uniformly distributed across this broad area. Sixty-one percent of the

breeding birds belong to the Interior population, while another 26

percent belong to the Atlantic population. Two major areas of

concentration are apparent in the vast range of the Interior

population: (1) the prairie lakes of Alberta, Manitoba, and

Saskatchewan (which account for 69 percent of the Interior population);

and (2) the U.S. and Canadian Great Lakes (accounting for another 12

percent).

Seven political units account for 70 percent of the North American

breeding birds, with Manitoba alone accounting for 36 percent. Thirty

(52 percent) of the 58 political units listed by Hatch (1995) each

harbor fewer than 100 breeding pairs. In the catfish-producing States

identified by Price and Nickum (1995), only Florida and California have

sizeable breeding populations

ther 12

percent).

Seven political units account for 70 percent of the North American

breeding birds, with Manitoba alone accounting for 36 percent. Thirty

(52 percent) of the 58 political units listed by Hatch (1995) each

harbor fewer than 100 breeding pairs. In the catfish-producing States

identified by Price and Nickum (1995), only Florida and California have

sizeable breeding populations.

In the south-central United States (Arkansas, Louisiana,

Mississippi, and west Tennessee), the double-crested cormorant has been

known since pre-colonial times and has been recorded as an occasional

breeder throughout the swampy forests of the region since at least the

early 1800s (Jackson and Jackson 1995). Jackson and Jackson predicted

that (in the absence of major limiting factors) the cormorant will once

again become a regular member of the mid-South breeding avifauna, with

birds dispersed more widely because of reservoir construction and with

concentrations expected in the vicinity of aquaculture facilities.

The double-crested cormorant has always been widely distributed as

a breeding species. The only suspected instance of range expansion in

the 20th century is in the United States and Canadian Great Lakes,

which apparently were colonized by birds expanding eastward from the

Canadian prairies beginning with Lake Superior about 1913 and ending

with lakes Erie and Ontario in the late 1930s (Weseloh et al. 1995). It

is possible, however, that these events represented recolonization of

former (but previously undocumented) breeding localities from which the

species was extirpated before 1912

Lakes,

which apparently were colonized by birds expanding eastward from the

Canadian prairies beginning with Lake Superior about 1913 and ending

with lakes Erie and Ontario in the late 1930s (Weseloh et al. 1995). It

is possible, however, that these events represented recolonization of

former (but previously undocumented) breeding localities from which the

species was extirpated before 1912. For example, although Barrows

(1912: 67) knew of no breeding records for Michigan, he noted that it

was ``generally distributed over the State during the migrations''

(with specimens from almost every county) and speculated that

``probably there are few sheets of water any size within our limits

which are not visited by this bird at least occasionally.''

The core of the wintering range (i.e., the regions of greatest

density) did not change appreciably between 1959-1972 and 1959-1988

(Root 1988: 11, Sauer et al. 1996b). Cormorant wintering populations

are concentrated in coastal States and Provinces, from North Carolina

to Texas in the east and from California to British Columbia in the

west. In the mid-South, there also are appreciable concentrations

inland from the coast (e.g., east Texas, eastern Oklahoma, southeastern

Arkansas, west-central Mississippi, and northeastern Alabama). Of the 9

catfish-producing States for which Christmas Bird Count data are

available, 6 have indices of relative abundance that exceed the

national mean; the median abundance in these 6 States (including the

major catfish-producers of Alabama, Louisiana, and Mississippi) was 2.0

times the national mean (range: 1.4-9.6).

The scattered occurrence of early winter stragglers throughout much

of the interior of the continent as far north as Minnesota and southern

Saskatchewan (Sauer et al. 1996b) is probably a natural phenomenon of

longstanding (i.e., it probably does not represent a northward

expansion of the wintering range)

Alabama, Louisiana, and Mississippi) was 2.0

times the national mean (range: 1.4-9.6).

The scattered occurrence of early winter stragglers throughout much

of the interior of the continent as far north as Minnesota and southern

Saskatchewan (Sauer et al. 1996b) is probably a natural phenomenon of

longstanding (i.e., it probably does not represent a northward

expansion of the wintering range). As evidence of this, we find that 11

percent of 227 winter recoveries (December-February 1923-1988) of birds

banded in Saskatchewan, Lake Huron, and eastern Lake Ontario were from

latitudes north of the major catfish-producing States of Alabama,

Arkansas, Louisiana, and Mississippi (Dolbeer 1991). Forty percent of

these 227 winter recoveries are from 1 deg. blocks of latitude and

longitude that intersect the Gulf Coast and another 22 percent are from

degree blocks that intersect the main stem of the Mississippi River.

Analysis of 5,589 band recovery records for the period 1923-1988

(Dolbeer 1991) revealed that southward movement from areas north of

latitude 42 deg.N occurs primarily in October and November. Cormorants

of all ages are at their greatest median distance from northern nesting

areas--about 1,900 kilometers (1,200 miles)--from December through

March.

Cormorants nesting in Canada and the northern United States from

Alberta to the Gulf of St. Lawrence migrate in winter primarily to the

southern United States between Texas and Florida. There is considerable

mixing and overlap in winter of nesting populations from widely

divergent areas. From 38 to 70 percent of the birds from Saskatchewan

through the Great Lakes region winter in the lower Mississippi Valley

(States of Arkansas, Louisiana, and Mississippi) as do 10 percent of

the birds from such disparate areas as Alberta and the New England

coast (Dolbeer 1991). In other words, the major catfish-producing

States of the lower Mississippi may be envisioned as lying at the apex

of an

to 70 percent of the birds from Saskatchewan

through the Great Lakes region winter in the lower Mississippi Valley

(States of Arkansas, Louisiana, and Mississippi) as do 10 percent of

the birds from such disparate areas as Alberta and the New England

coast (Dolbeer 1991). In other words, the major catfish-producing

States of the lower Mississippi may be envisioned as lying at the apex

of an

inverted triangle, with cormorants from a 3,000 kilometer (1,860 mile)

expanse of breeding range being funneled into the region in the winter

by topographic features and the flow of the major rivers. In commenting

on this funneling effect, Jackson and Jackson (1995) noted that ``It is

a most unfortunate coincidence that the very heart of the catfish-

farming industry is located in the Mississippi Delta at the confluence

of the Arkansas and Mississippi rivers.''

Our knowledge of double-crested cormorant population trends before

1959 is based on fragmented and largely anecdotal accounts from

scattered portions of the range. Syntheses of much of this information

(Hatch 1995, Weseloh et al. 1995, and Jackson and Jackson 1995) reveal

the following general patterns: (1) by 1900, cormorant numbers had been

reduced, and their range possibly restricted, by human persecution and

the extensive drainage and degradation of natural wetlands; (2) the

widespread construction of reservoirs and impoundments (beginning in

the 1920s), in concert with sport fish stocking programs and the

creation of refuges and other conservation lands (beginning in the

1930s), had beneficial effects on cormorant numbers; (3) the widespread

use of DDT and other pesticides (beginning in the 1940s) had

devastating effects on cormorant reproductive success, with the result

that populations reached their lowest point in the mid-1970s; (4) the

ban on DDT in 1972 and the general decrease in levels of environmental

contamination, in concert with development of the catfish industry in

the mid-1970s, created a favorable environment for the gro

DDT and other pesticides (beginning in the 1940s) had

devastating effects on cormorant reproductive success, with the result

that populations reached their lowest point in the mid-1970s; (4) the

ban on DDT in 1972 and the general decrease in levels of environmental

contamination, in concert with development of the catfish industry in

the mid-1970s, created a favorable environment for the growth of

cormorant populations.

Quantitative information on double-crested cormorant population

trends is available from three sources: (1) Breeding Bird Survey data

(1966-1994), (2) Christmas Bird Count data (1959-1988), and (3)

published accounts of censuses of breeding colonies. Trend information

from these sources is discussed in the following paragraphs:

(1) Between 1966 and 1994, the continental breeding population

increased at an estimated rate of 6.1 percent/year (Sauer et al.

1996a). The very high rate of growth in the early years (13.0 percent/

year), and to a lesser extent for the entire period, is partly an

artifact of the extremely small population in the early years of the

survey period (late 1960s and early 1970s). Compared to the earlier

(1966-1979) time period, the growth of the continental and Canadian

populations appears to have slowed appreciably in the later (1980-1994)

period; however, the U.S. population has continued to show a

significant rate of increase in the 1980s and 1990s, apparently due

primarily to the continued rapid growth of populations in the mountains

and plains States. The only significant declines noted were in the West

Coast region (1966-1994) and in North Dakota (1980-1994), although the

West Coast trend appears to be contradicted by rather dramatic site-

specific increases in British Columbia, Washington, and California

(Carter et al. 1995). Most of the recent increase in numbers has

occurred within the known historical breeding range (Hatch 1995).

ates. The only significant declines noted were in the West

Coast region (1966-1994) and in North Dakota (1980-1994), although the

West Coast trend appears to be contradicted by rather dramatic site-

specific increases in British Columbia, Washington, and California

(Carter et al. 1995). Most of the recent increase in numbers has

occurred within the known historical breeding range (Hatch 1995).

(2) Between 1959 and 1988, the continental wintering population

increased at an average rate of 7.3 percent/year (Sauer et al. 1996b);

significant increases were registered for 17 of the 20 States or

Provinces for which data were available. Trends are available for 9 of

the primary catfish-producing States; 6 of these States (Alabama,

Louisiana, Mississippi, Oklahoma, Texas, and Virginia) have trends

(median 16 percent, range 12-19 percent) that are well above the

continental average. Most of the localities in the mid-South for which

information is available show dramatic population increases between the

mid-1970s and the early 1990s, with the trends paralleling a similar

magnitude of growth in the area of catfish ponds in the region during

the same period (Jackson and Jackson 1995).

(3) Rather dramatic increases in breeding pairs are documented at

colonies in the Great Lakes (Weseloh et al. 1995), the St. Lawrence

River and associated waters (Chapdelaine and Bedard 1995), New England

(Krohn et al. 1995), the West Coast (Carter et al. 1995), and elsewhere

(Weseloh et al. 1995). The trends documented by these studies generally

parallel those from the Breeding Bird Survey and the Christmas Bird

Count.

Foraging Behavior of the Double-crested Cormorant at Aquaculture

Facilities

al. 1995), the St. Lawrence

River and associated waters (Chapdelaine and Bedard 1995), New England

(Krohn et al. 1995), the West Coast (Carter et al. 1995), and elsewhere

(Weseloh et al. 1995). The trends documented by these studies generally

parallel those from the Breeding Bird Survey and the Christmas Bird

Count.

Foraging Behavior of the Double-crested Cormorant at Aquaculture

Facilities

Daily Movements and Activity Budgets. In the Mississippi Delta,

cormorants fly an average of 16 kilometers (25 miles) from their night

roosts to feeding sites. Each bird spends about 18 percent of daylight

hours feeding; 88 percent of their foraging is done at catfish ponds

and 12 percent near roost sites. The average cormorant forages for 60

minutes each day, but spends just 20 minutes underwater in actual

pursuit of fish (King et al. 1995).

Feeding Rates. Feeding rates may be dependent on the size and

abundance of the available fish and the metabolic demands of the birds,

and can be quite variable. Actively feeding cormorants in commercial

catfish ponds capture an average of about 5 fish/cormorant/hour

(Stickley 1991, Stickley et al. 1992), but can vary from 0-28 (Schramm

et al. (1984). Partly because of this variability, the rate of 5 fish/

cormorant/hour reported by Stickley et al. (1992) is highly skewed; the

median was only 2 fish/cormorant/hour, and the mean was equaled or

exceeded at only 3 (21 percent) of the 14 ponds studied. Stickley et

al. (1992) did not find a significant relationship between the mean

number of cormorants present and the number of catfish consumed, but

ponds with 40 or more cormorants generally had a feeding rate of 1 or

fewer fish/cormorant/hour. Similarly, cormorant feeding rates were not

related to the density of fingerling catfish, density of all catfish

(all size classes combined), or mean length of fish .

Diet Composition

a significant relationship between the mean

number of cormorants present and the number of catfish consumed, but

ponds with 40 or more cormorants generally had a feeding rate of 1 or

fewer fish/cormorant/hour. Similarly, cormorant feeding rates were not

related to the density of fingerling catfish, density of all catfish

(all size classes combined), or mean length of fish .

Diet Composition. Cormorants eat a wide variety of prey items, and

there is thus a great deal of variation in prey composition, both

geographically and seasonally. Nearly all of the published information

on diet composition at aquaculture facilities has been gathered in the

vicinity of catfish farms in the southeastern United States (Bivings

1989, Conniff 1991, Glahn and Stickley 1992, Glahn et al. 1995, and

Glahn and Brugger 1995). These studies show that, among birds actively

feeding on catfish ponds, the average proportion of catfish in the

winter diet (by number) is most commonly in the range of 50-55 percent.

The proportion varies seasonally from less than 30 percent in October

and November to more than 80 percent in February, March, and April.

Prey Size. Although cormorants are capable of taking catfish up to

42 centimeters (16 inches) in length (Campo et al. 1993), studies

repeatedly have shown that the vast majority of catfish caught by

cormorants at commercial facilities are in the range of 7-20

centimeters (3-8 inches), with most averaging about 10-15 centimeters

(4-6 inches) (Schramm et al. 1984, Stickley 1991, Stickley et al.

1992). This range of prey sizes is remarkably close to that of prey

taken by cormorants in natural freshwater habitats. In five such

studies (Durham 1955, Hirsch 1986, Haws 1987, Hobson et al. 1989, Campo

et al. 1993), prey size ranged from 6-21 centimeters (2-8 inches), with

a median value of about 12 centimeters (5 inches).

Prey Preferences

hramm et al. 1984, Stickley 1991, Stickley et al.

1992). This range of prey sizes is remarkably close to that of prey

taken by cormorants in natural freshwater habitats. In five such

studies (Durham 1955, Hirsch 1986, Haws 1987, Hobson et al. 1989, Campo

et al. 1993), prey size ranged from 6-21 centimeters (2-8 inches), with

a median value of about 12 centimeters (5 inches).

Prey Preferences. Lacking a precise knowledge of the species

composition and size distribution of the prey population, it is

impossible to make definitive statements about prey preferences.

However a few tendencies

are apparent. For example, the 10-15 centimeter (4-6 inch) fingerling

catfish preferred by cormorants in one study represented about 64

percent of the catfish (by number) in the ponds (from Stickley et al.

1992), suggesting that the birds were merely preying on the most

readily available fish. In this same study, 1 of the 14 ponds contained

gizzard shad in addition to catfish. Nineteen shad were consumed for

every catfish eaten, even though the pond contained about 5,100

fingerling catfish/hectare (2,100/acre). The apparent preference for

gizzard shad in this instance may be related to their being more easily

caught, handled, and swallowed by cormorants (the mean handling time

for catfish was 6-7 times greater than that of gizzard shad).

Daily Food Consumption Rates. Estimates of daily food consumption

rates of cormorants at or in the vicinity of aquaculture facilities in

the southeastern United States vary widely, from 208-504 grams (7-17

ounces, or 0.4-1.1 pounds) (Schramm et al. 1984, Schramm et al. 1987,

Bivings et al. 1989, Conniff 1991, Brugger 1993, Glahn and Brugger

1995). The most widely accepted figure is about 320 grams (11 ounces,

or 0.7 pounds) of fish/day, of which about one-half (or 160 grams [5.5

ounces, or 0.35 pounds]) would be catfish (Brugger 1993).

Impacts of Double-crested Cormorants on Aquaculture

(7-17

ounces, or 0.4-1.1 pounds) (Schramm et al. 1984, Schramm et al. 1987,

Bivings et al. 1989, Conniff 1991, Brugger 1993, Glahn and Brugger

1995). The most widely accepted figure is about 320 grams (11 ounces,

or 0.7 pounds) of fish/day, of which about one-half (or 160 grams [5.5

ounces, or 0.35 pounds]) would be catfish (Brugger 1993).

Impacts of Double-crested Cormorants on Aquaculture

With the exception of catfish, quantitative accounts of the impacts

of cormorants on freshwater aquaculture stocks generally are lacking.

The fairly large body of literature that has developed in the past 12

years represents an attempt to assess the impacts of cormorants on the

commercial catfish industry. Synopses of the pertinent literature are

given in the following paragraphs.

In the past, cormorants have been reported only infrequently at

fish hatcheries. For example, questionnaire surveys conducted in 1977

(Scanlon et al. 1979) and 1984 (Parkhurst et al. 1987) indicate that

cormorants were considered to be problems at only 4-5 percent of these

facilities nationwide. Of the more than 90 other (including non-avian)

species mentioned as predators, 45-50 percent were listed more

frequently than cormorants. Purported instances of cormorant damage to

hatchery fish in Texas (Dukes 1987) include the loss of 90 percent of

the smallmouth bass (Micropterus dolomieui) 2-year-old brood stock at

the Jasper facility.

The frequency of occurrence of cormorants at a given catfish pond

is a function of many interacting factors, including: (1) size of the

regional cormorant population; (2) the number, size, and distribution

of catfish ponds; (3) the size distribution, density, health, and

species composition of fish populations in the catfish ponds; (4) the

number, size, and distribution of ``natural'' wetlands in the immediate

environs; and (5) the size distribution, density, health, and species

composition of ``natural'' fish populations in the surrounding

landscape

ion; (2) the number, size, and distribution

of catfish ponds; (3) the size distribution, density, health, and

species composition of fish populations in the catfish ponds; (4) the

number, size, and distribution of ``natural'' wetlands in the immediate

environs; and (5) the size distribution, density, health, and species

composition of ``natural'' fish populations in the surrounding

landscape. Cormorants are adept at seeking out the most favorable

foraging sites. As a result, cormorants rarely are distributed evenly

over a given region, but rather tend to be highly clumped or localized.

For example, in 27 weekly surveys at 50 catfish ponds in Humphreys

County, Mississippi, 1987-1988, cormorants were observed at only 9 of

the 50 ponds and only on 14 occasions (Hodges 1989). Thus, it is not

uncommon for many fish farmers in a region to suffer little or no

economic damage from cormorants, while a few farmers experience

exceptionally high losses.

Cormorants clearly respond in a positive way to the presence of

shallow-water ponds stocked with high densities of easy-to-capture prey

fish. For example, within two weeks of stocking 2 ponds in Hendry

County, Florida, with 5-20 centimeter (2-8 inch) fingerling catfish, 12

cormorants were feeding in the ponds and roosting on nearby poles. A

nearby 2.5 hectare (6 acre), 2.5-meter (8-foot) deep pond, stocked with

75,000 3-8 centimeter (1-3 inch) fish in August 1980, had attracted 13

cormorants by September. These birds continued to feed at the pond

throughout the fall and winter, and in spring 1981 they nested in a

nearby cypress dome. By November 1981, about 50 cormorants were feeding

in the pond (Schramm et al. 1984)

y poles. A

nearby 2.5 hectare (6 acre), 2.5-meter (8-foot) deep pond, stocked with

75,000 3-8 centimeter (1-3 inch) fish in August 1980, had attracted 13

cormorants by September. These birds continued to feed at the pond

throughout the fall and winter, and in spring 1981 they nested in a

nearby cypress dome. By November 1981, about 50 cormorants were feeding

in the pond (Schramm et al. 1984). The positive response of cormorants

to the presence of shallow-water ponds stocked with high densities of

easy-to-capture prey fish (as illustrated above) is clearly a major

factor responsible for their impacts in a variety of aquaculture

situations (e.g., baitfish ponds in Minnesota, koi ponds in Missouri

and elsewhere, ornamental fish ponds in Florida, and catfish pods in

the southeastern United States and elsewhere).

Assuming averages of 5 fingerling catfish consumed/cormorant/hour

and 30 cormorants/pond (a constant number of feeding birds present

throughout an 8 hour day), the catfish population of a typical pond in

the Mississippi Delta (51,000 fish/hectare in a 8-hectare pond, which

is equivalent to 20,650 fish/acre in a 20-acre pond) would be halved in

167 days (Stickley et al. 1992). However, if actual values were nearer

the median values of 2 fish/cormorant/hour and 15 birds/pond (from

Stickley et al. 1992), the number of days required for the cormorants

to reduce the population by half would be increased to 850 days (a 5-

fold increase).

Of 281 catfish farmers queried on the Mississippi Delta in 1988

(Stickley and Andrews 1989), 87 percent felt that they had a bird

problem. Moderate to heavy cormorant activity (defined as at least 25

birds/day) was reported by 57 percent of Delta farmers. Losses to birds

(harassment costs plus value of fish lost) were estimated at $5.4

million (3 percent of total sales)

(a 5-

fold increase).

Of 281 catfish farmers queried on the Mississippi Delta in 1988

(Stickley and Andrews 1989), 87 percent felt that they had a bird

problem. Moderate to heavy cormorant activity (defined as at least 25

birds/day) was reported by 57 percent of Delta farmers. Losses to birds

(harassment costs plus value of fish lost) were estimated at $5.4

million (3 percent of total sales).

Overall, there appears to be little conflict between cormorants and

the food- or game-fish industry in Florida (Brugger 1992), but losses

of food fish, primarily catfish, can be locally severe (Brugger 1995);

for example, cormorants were responsible for the loss of up to 50

percent of the fingerling catfish in open 0.125 hectare (0.31 acre)

ponds during 1991 at the University of Florida.

Although fish of commercial value made up only a small percentage

of the diet of cormorants collected in the vicinity of aquaculture

facilities in central and southeast Arkansas from mid-October to early

December, the finding of a few fish of very high value (e.g., grass

carp with wholesale value of about $4.00 and koi worth $5.00-10.00

each) suggests that cormorant depredations can be locally or seasonally

severe.

On the Mississippi Delta, cormorants consumed an estimated 18-20

million catfish during the winters of 1989-1990 and 1990-1991, which

was equivalent to 842-939 metric tons (928-1,035 short tons, or 1.86-

2.07 million pounds, or 844-939 thousand kilograms). Based on the cost

of replacing these fish, annual losses to the catfish industry were

estimated at $1.8-2.0 million, which corresponds to about 4 percent of

the estimated catfish standing crop each year. Although losses were

documented over a six-month period, the majority (about 64-67 percent)

occurred in February and March (Glahn and Brugger 1995)

ion pounds, or 844-939 thousand kilograms). Based on the cost

of replacing these fish, annual losses to the catfish industry were

estimated at $1.8-2.0 million, which corresponds to about 4 percent of

the estimated catfish standing crop each year. Although losses were

documented over a six-month period, the majority (about 64-67 percent)

occurred in February and March (Glahn and Brugger 1995).

At catfish farms in Oklahoma (with about 324 hectares [800 acres]

of surface water in production) in 1993, cormorants consumed an

estimated 7,196 kilograms (15,900 pounds, or 7.9 short tons) of catfish

valued at $14,000-36,000 (depending on size of the fish consumed), or

about 3-7 percent of Oklahoma catfish sales (Simmonds et al. 1995).

Cormorant Depredation Permits

Depredation permits to take double-crested cormorants at commercial

aquaculture facilities have been issued by the Fish and Wildlife

Service since 1986. Composite data for a recent two-year period (1993-

1994) show that about 8,200 cormorants were taken each year by 2,261

permit holders. Cormorants represented the majority (about 57 percent)

of the total number of birds killed nationwide; two-thirds of the

cormorants were taken in the southeastern region of the United States,

with substantial numbers also taken in the southwest and the upper

Midwest.

Between 1989 and 1996, the number of permits issued to take double-

crested cormorants in the southeastern United States more than

quadrupled, from 50 to 215 (Coon et al. 1996). The reported take of

4,000-8,000 birds annually has had no noticeable effect on the size of

the regional wintering population.

Mastrangelo et al. (1995) noted that the reported take never

exceeded 68 percent of the authorized take and attributed this to the

frightening effect that lethal control has on bird behavior. Hess

nited States more than

quadrupled, from 50 to 215 (Coon et al. 1996). The reported take of

4,000-8,000 birds annually has had no noticeable effect on the size of

the regional wintering population.

Mastrangelo et al. (1995) noted that the reported take never

exceeded 68 percent of the authorized take and attributed this to the

frightening effect that lethal control has on bird behavior. Hess

(1994) described a recent study in which catfish farmers at three

complexes in Mississippi were authorized (under Fish and Wildlife

Service permits) to remove as many as 2,500 cormorants in a 19-week

period. Participants were supplied with ammunition and encouraged to

kill as many birds as allowed by the permit. The fact that only 290

birds had been killed by the end of the project was attributed to a

learned behavior by the birds to avoid areas where they might be shot

(Hess 1994).

Environmental Consequences of Proposed Action

Cormorant Population. The proposed action (a depredation order) is

expected to result in a moderate increase in the number of double-

crested cormorants taken at aquaculture facilities. The impact is

expected to be localized (e.g., possible reductions in the size of

wintering populations in the immediate vicinity of catfish farms). To

calculate the potential maximum harvest, we can assume that 42

cormorants (the average number reported taken by holders of depredation

permits in the southeastern United States, 1989-1995; from Coon et al.

1996) will be shot at each of the about 2,200 catfish farms in the

United States. The resultant annual take of 92,400 birds will represent

about 5-10 percent of the continental population. This level of take

will be more than offset by the recruitment of young birds into the

population; a reproductive success of 1.7-3.2 young/nest (Duffy 1995)

will equate to a minimum recruitment, at current population levels, of

612,000 young into the population each year

United States. The resultant annual take of 92,400 birds will represent

about 5-10 percent of the continental population. This level of take

will be more than offset by the recruitment of young birds into the

population; a reproductive success of 1.7-3.2 young/nest (Duffy 1995)

will equate to a minimum recruitment, at current population levels, of

612,000 young into the population each year. In reality, the proposed

action is expected to result in only a modest increase in the number of

double-crested cormorants taken at aquaculture facilities.

Socio-Economic. The proposed action is expected to reduce the

direct economic losses caused by cormorants at commercial aquaculture

facilities. It also will enhance the effectiveness of current nonlethal

control programs, thus reducing overall damage control costs to

producers. The proposed depredation order will reduce paperwork and

costs associated with administering the current permit system and will

promote quicker and more efficient depredation control operations by

shifting responsibility to the individual aquaculturists. A depredation

order will demonstrate cooperation between the Federal agency

responsible for protecting and enhancing wildlife (Service), the

Federal agency responsible for dealing with wildlife damage issues

(ADC), and the individual producers in dealing with a problem that has

the potential to expand far beyond the wildlife management arena.

Other Fish-Eating Birds. Although the proposed action does not

authorize the taking of other fish-eating birds, it is possible that a

few birds could be taken accidentally on occasion. The two species that

are most likely to be confused with the double-crested cormorant are

the neotropic cormorant (Phalacrocorax brasilianus) and the anhinga

(Anhinga anhinga). These species have foraging habits very much like

those of the double-crested cormorant and may occur on or in the

vicinity of catfish ponds in the Gulf Coast States

few birds could be taken accidentally on occasion. The two species that

are most likely to be confused with the double-crested cormorant are

the neotropic cormorant (Phalacrocorax brasilianus) and the anhinga

(Anhinga anhinga). These species have foraging habits very much like

those of the double-crested cormorant and may occur on or in the

vicinity of catfish ponds in the Gulf Coast States. The likelihood of

other fish-eating birds being mistaken for double-crested cormorants

and shot accidentally is not expected to increase above that which

presently occurs . However, because of a projected increase in the

number of producers conducting lethal control operations for

cormorants, it is possible that there will be a slight to moderate

increase in the actual number of other fish-eating birds (especially

neotropic cormorants and anhingas) taken accidentally. Any negative

effects on these species would be extremely localized, and long-term

impacts on populations would be unlikely.

Endangered and Threatened Species. Negligible impacts to endangered

or threatened species are expected under the proposed action. Few

endangered or threatened species have ever been taken by aquaculturists

with depredation permits. The likelihood of endangered or threatened

species being taken by accident is not expected to increase under the

proposed action.

Public Comments Invited

The policy of the Department of the Interior is, whenever

practical, to afford the public an opportunity to participate in the

rulemaking process. Accordingly, interested persons may submit written

comments, suggestions, or objections regarding this proposal to the

location identified in the addresses caption. Comments must be received

on or before August 22, 1997. Following review and consideration of the

comments, the Service will issue a final rule on these proposed

amendments.

National Environmental Policy Act

rulemaking process. Accordingly, interested persons may submit written

comments, suggestions, or objections regarding this proposal to the

location identified in the addresses caption. Comments must be received

on or before August 22, 1997. Following review and consideration of the

comments, the Service will issue a final rule on these proposed

amendments.

National Environmental Policy Act

In accordance with the National Environmental Policy Act of 1969,

the Service has prepared an Environmental Assessment of the proposed

action, and a Finding of No Significant Impact has been issued. Copies

of these documents are available from the Chief, Office of Migratory

Bird Management, U.S. Fish and Wildlife Service, 4401 North Fairfax

Drive, ms 634--ARLSQ, Arlington, VA 22203.

Endangered Species Act Consideration

Consultations will be initiated to ensure that actions resulting

from this proposal will not likely jeopardize the continued existence

of endangered or threatened species or result in the destruction or

adverse modification of their critical habitat. Findings from these

consultations will be included in a biological opinion and may cause

modification of some regulatory measures proposed in this document. The

final rule will reflect any such modifications.

Regulatory Flexibility Act, Executive Order (E.O.) 12866 and

Paperwork Reduction Act

Based on the economic impacts discussed above, the Service has

determined under the Regulatory Flexibility Act of 1980 (5 U.S.C. 601

et seq.) that this rulemaking would not have a significant effect on a

substantial number of small entities, which include businesses,

organizations and governmental jurisdiction. This rule was not subject

to review by the Office of Management and Budget under E.O 12866.

The Service examined the proposed rule under the Paperwork

Reduction Act of 1995 and found that it does not

contain information collection requirements.

Unfunded Mandates

ederal

Regulations, as set forth below:

PART 21--[AMENDED]

1. The authority citation for part 21 continues to read as follows:

Authority: Pub. L. 95-616, 92 Stat. 3112 (16 U.S.C. 712(2)).

Subpart D--Control of Depredating Birds

2. Part 21, subpart D, is amended by adding Sec. 21.47 to read as

follows:

Sec. 21.47 Depredation order for double-crested cormorants at

aquaculture facilities.

In all States in the contiguous 48 States except Arizona,

California, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New

Mexico, North Dakota, Oregon, South Dakota, Utah, Washington, and

Wyoming, persons actually engaged in the production of aquaculture

commodity stocks may, without a Federal permit, take double-crested

cormorants when found committing or about to commit depredations to

aquaculture stocks on the premises owned or occupied by such persons:

Provided that:

(a) Double-crested cormorants may be taken only by shooting, and

only when necessary to protect freshwater commercial aquaculture and

State-operated hatchery stocks from depredation; none of the birds so

taken may be sold or removed from the area where killed; and all dead

birds must be buried or incinerated within this area, except that any

specimens needed for scientific purposes as determined by the Director

must not be destroyed.

(b) Double-crested cormorants may be shot at freshwater commercial

aquaculture facilities or State-operated hatcheries only in conjunction

with an established non-lethal harassment program approved by the

Animal Damage Control program of the U.S. Department of Agriculture's

Animal and Plant Health Inspection Service.

(c) Double-crested cormorants may be shot only within the

boundaries of freshwater commercial aquaculture facilities or State-

operated hatcheries.

(d) No person operating under the provisions of this section may

use decoys, taped calls, or other devices to lure birds within gun

range.

Damage Control program of the U.S. Department of Agriculture's

Animal and Plant Health Inspection Service.

(c) Double-crested cormorants may be shot only within the

boundaries of freshwater commercial aquaculture facilities or State-

operated hatcheries.

(d) No person operating under the provisions of this section may

use decoys, taped calls, or other devices to lure birds within gun

range.

(e) Any person exercising the privileges of this section must

permit, at all reasonable times, Federal or State wildlife enforcement

officers access to the premises on which the operations have been or

are being conducted; and must furnish to the officers whatever

information they may reasonably require concerning the operations,

including a log of the number of double-crested cormorants killed.

(f) Nothing in this section authorizes the killing of double-

crested cormorants contrary to the laws or regulations of any State,

and none of the privileges of this section may be exercised unless the

person possesses the appropriate State permits, when required.

(g) Unless specifically extended, the authority granted in this

section will automatically expire on April 30, 2005.

Dated: June 9, 1997.

William Leary,

Acting Deputy Assistant Secretary for Fish and Wildlife and Parks.

[FR Doc. 97-16395 Filed 6-20-97; 8:45 am]

Billing Code: 4310-55-F