Agriculture and Resource Protection 

 Researcli Program 



TITLE: Defining Economic Impacts and 



Developing Strategies for Reducing Avian 

 Predation in Aquaculture Systems 



GOAL: Develop an understanding of the economic 

 impacts of damage inflicted on aquaculture 

 production systems by cormorants, 

 pelicans, wading birds, and waterfowl and 

 develop tools and techniques for reducing 

 that damage. 



In the past 30 years, populations of fish-eating birds 

 have increased dramatically and caused substantial 

 economic impacts to aquaculture production. 

 Aquaculture industry costs associated with bird 

 damage and damage prevention are estimated to 

 exceed $25 million annually for double-crested 

 cormorants (DCCOs) alone. The goal of NWRC's 

 research is to determine the impact of fish-eating 

 birds on aquaculture production and natural 

 resources and to develop methods to reduce 

 depredations of catfish, baitfish, and crawfish 

 industries in the Southeast. Current research is 

 aimed at gaining information about the abundance, 

 distribution, and foraging behavior of fish-eating 

 birds; the economic impacts associated with their 

 foraging activities; and the diseases they transmit at 

 aquaculture facilities. This information will help to 

 develop new techniques for reducing damage. 



NWRC Scientists Study the Reproductive Status 

 of DCCOs in the Eastern United States— The 

 recent abundance and foraging habits of DCCOs 

 have thrust this species into conflict with the 

 aquaculture industry and fisheries interests over 

 both perceived and documented impacts to natural 

 and commercial resources. Consequently, resource 

 managers are aggressively employing control 

 measures on DCCOs' breeding, migratory, and 



Commercial catfish production is a vital industry in the 

 Southeastern United States. NWRC scientists are studying the 

 economic impacts of DCCOs on this industry. 



wintering areas to alleviate damage. Unfortunately, 

 the breeding biology of cormorants is poorly 

 understood, and without this basic knowledge, 

 scientists cannot accurately predict the effects 

 of management on cormorant populations nor 

 attribute observed changes in reproductive 

 success and population size to management 

 actions. To better understand the breeding biology 

 of cormorants, NWRC scientists began a study 

 in 2007 to determine their reproductive status 

 in the Northeastern, Midwestern, and Southern 

 United States. This study will allow researchers 

 to determine the proportion of nonbreeding 

 individuals associated with breeding assemblages 

 of cormorants and use this knowledge to improve 

 population estimates of cormorants across the 

 breeding range. 



Developing Methods 5 



