Assisting American Aquaculture

Annual fi sh production in the United States is valued at $1 billion. Fish 

production in the United States continues to be important, particularly in 

the East, where millions of dollars worth of catfi sh, tilapia, trout, baitfi sh, 

ornamental fi sh, shellfi sh, and crawfi sh are grown and harvested annually. 

For example, in 2007, aquaculture producers sold more than $53 million 

in Idaho trout (37 million pounds), more than $230 million in Mississippi 

catfi sh (280 million pounds), and $110 million in Arkansas catfi sh and 

baitfi sh.

Wildlife Problems at Fish Farms

Aquaculture producers report that fi sh-eating birds cause signifi cant 

economic loss. A single day of foraging by a fl ock of 250 American white 

pelicans could cost a catfi sh farmer as much as $3,000. Some operations 

report 1-year losses in excess of $200,000. In the Delta region of 

Mississippi, cormorants eat $10 to 13 million worth of channel catfi sh each 

year.

 In addition to predation, fi sh-eating birds can spread fi sh diseases. 

The American white pelican is a host of the trematode Bolbophorus 

damnifi cus and has been known to spread this parasite to commercial 

catfi sh farms. The resulting economic losses can be severe, as 

B. damnifi cus infection can cause high mortalities in catfi sh or make them 

unmarketable. Fish-eating birds also can spread the parasite that causes 

whirling disease in trout and salmon. This disease poses a signifi cant threat 

to coldwater sportfi sh. Within weeks of being infected, the fi sh sustain 

Protecting People

Protecting Agriculture

Protecting Wildlife

Wildlife Services Factsheet

November 2010

Assisting American 

Aquaculture

Wildlife Services (WS), a 

program within the U.S. 

Department of Agriculture’s 

Animal and Plant Health 

Inspection Service (APHIS), 

provides Federal leadership 

and expertise to reduce 

wildlife damage to the Nation’s 

agriculture, natural resources, 

human health and safety, 

and property. Fish farmers 

turn to WS for responsible 

and environmentally sound 

solutions for damage caused 

by wildlife, which can cost the 

aquaculture industry millions of 

dollars.

A propane cannon is 

one noisemaking method 

used to disperse birds. 
nerve damage and skeletal deformities that cause them 

to swim erratically in a “whirling” motion and have 

diffi culty feeding and avoiding predators. 

Minimizing Losses

When fi sh farmers need responsible and 

environmentally sound solutions for damage caused 

by wildlife, they turn to WS. The program’s wildlife 

biologists conduct on-site evaluations to assess 

damage and identify the species causing it. They offer 

recommendations and technical advice, as well as 

management assistance, to aquaculture producers. 

WS recommends and conducts integrated wildlife 

damage management programs that consider and 

include the application of a variety of methods. At 

aquaculture facilities, these methods often include 

scaring and exclusionary techniques such as netting 

and noisemakers.

 WS encourages the use of netting, wire grids, and 

fencing, which offer fi sh farmers long-term protection 

against wildlife damage. For some farmers, however, 

the cost associated with the installation of the physical 

barriers makes them impractical. In addition, some 

farmers report that the barriers interfere with normal 

fi sh-rearing operations and require substantial 

monitoring and repairs. 

 For additional relief, WS recommends noisemakers, 

such as propane cannons and cracker shells, and 

visual devices, like “eye-spot” balloons, remote-control 

boats and airplanes, and scarecrows. Unfortunately, 

many birds quickly adapt to the sight and sound of 

such devices. If exclusionary and scaring techniques 

fail to reduce losses, the U.S. Department of the 

Interior’s Fish and Wildlife Service (FWS) can issue a 

depredation permit to remove a limited number of birds 

from a specifi c farm. Removal can make nonlethal 

control methods more effective. When WS assists in 

lethal removal, the methods and numbers of birds 

removed is controlled and can be carried out with 

limited environmental impacts. 

 The issuance of permits is rigidly controlled because 

most fi sh-eating birds are protected by the Migratory 

Bird Treaty Act. The Public Resource Depredation 

Order (50 CFR§21.48) authorizes State fi sh and wildlife 

agencies, federally recognized tribes, and USDA’s WS 

to lethally remove cormorants when they are causing 

damage to public resources.

Research Projects

Given aquaculture’s importance as a source of food 

for American consumers, USDA’s National Wildlife 

Research Center (NWRC) conducts research and fi eld 

studies to develop new damage management methods 

and to improve existing ones. The majority of the 

NWRC’s research concentrates on the development 

and refi nement of nonlethal control methods.

In addition, WS continues to work with FWS to study 

the ecology, behavior, food habits, population modeling, 

and migratory patterns of fi sh-eating birds. 

The Public Resource Depredation Order (50 CFR§21.48) authorizes State fi sh and wildlife 

agencies, federally recognized tribes, and USDA’s WS to lethally remove cormorants when they 

are causing damage to public resources.

A WS biologist prepares 

a bird specimen for 

submission to the 

laboratory where 

stomach contents can 

be analyzed for disease 

and parasite research.
 NWRC scientists have identifi ed that cormorants are 

as likely to feed at catfi sh ponds containing food fi sh as 

at fi ngerling ponds. Because catfi sh in food fi sh ponds 

have higher value, farmers should focus management 

efforts to minimize those losses. NWRC continues 

efforts to document the distribution and growth of 

double-crested cormorant populations. This research 

will be used to develop regional and fl yway-based 

population management strategies.

Additional Information

For more information about aquaculture and WS, 

contact 1-866-4USDA-WS (1-866-487-3297) or visit 

the program’s Web site at www.aphis.usda.gov/wildlife_

damage/.

The U.S. Department of Agriculture is an equal opportunity provider and employer.

Mention of companies or commercial products does not imply recommendation or endorsement by the USDA over others not mentioned. The USDA neither guarantees 

nor warrants the standard of any product mentioned. Product names are mentioned solely to report factually on available data and to provide specifi c information. 

United States Department of Agriculture

Animal and Plant Health Inspection Service