ECONOMICS OF WILDLIFE CONTROL AND PERMITTING TO LIMIT DAMAGE TO AQUACULTURE

A wide variety of wildlife can cause significant losses of commercially produced aquaculture products depending on the location and type of farm. However, the most problematic type of wildlife typically are birds. Cormorants, wading birds, pelicans, and even ducks and blackbirds forage at commercial catfish, crawfish, baitfish, ornamental fish, and trout farms. Most birds are protected by state and federal laws, so fish farmers must rely on nonlethal techniques to accomplish control objectives or must obtain special permits. A federal depredation permit allows a farmer to capture or kill birds to reduce damage or to protect other interests such as human health and safety or personal property.

A fundamental aspect of all wildlife control to protect aquaculture resources is do the benefits of control outweigh the costs. There are costs associated with obtaining permits for wildlife control, however these are minor relative to control costs themselves. For example permit costs to control birds on catfish aqculture in Mississippi are about $125.00 (U.S.)/year. Whereas average annual wildlife control costs on Mississippi catfish aquaculture farms were estimated at $15,500 (2013 U.S. dollars). Savings to producers can be substantial for effective wildlife control programs. For trout aquaculture in California annual losses at 2 hatcheries were $50,000 to $60,000. After exclusion, production increased 25 to 30% at both facilities and the return on investment was realized within 3 to 4 years. For catfish aquaculture in Mississippi on a 104 ha farm, savings over average control costs could be as high as $323 per ha annually, depending on farm practices and predation level (Figure 1).   

Producers can optimize current control efforts by understanding and considering the costs, and limitations of different techniques and by developing integrated strategies for their use. Wildlife control methods typically fall into a few major categories: exclusion or barriers, frightening and dispersal methods, lethal control, and changes in culture practices. The different aquaculture products and production methods used and the wildlife species causing damage will determine the best methods to use. Other than complete exclusion, most wildlife damage problems require an integrated approach to be successful.