Bird Depredation

Background

Piscivorous birds can cause significant predation on farm raised fish and shellfish. Several bird species (e.g. blue heron, black crowned night heron, pelican, cormorant and kingfisher) can consume considerable quantities of these animals. Fish not consumed may be physically damaged during attempted predation. Birds may also serve as disease vectors spreading pathogens amongst fish farms or transferring pathogens from the wild to a fish farm.

Control of piscivorous birds can be difficult and expensive. All piscivorous birds are federally protected. Depredation permits can be obtained but these are not usually issued in a timely manner. Bird dissuasion devices (e.g. cannons and/or other scare devices) are of limited success. Exclusion devices such as cages that cover the entire rearing area are expensive, interfere with routine fish rearing activities, and may not readily withstand the rigors of winter weather (i.e. ice and snow). Considerable need exists to develop improved bird management techniques.

The NAA Recommends:

1. The U.S. Fish and Wildlife Service manage migratory bird numbers on basis of wild food supply. Where bird numbers exceed wild food supplies, hence allowing for excessive farmed fish depredation, these numbers must be reduced.
2. The USDA Wildlife Services program should be encouraged to actively develop additional control measures.
3. Cumbersome regulatory processes that impede bird control efforts should be removed.
4. Depredation permits should be readily available on a timely basis and should be administered equally by all U.S. Fish and Wildlife regions.
5. Standing depredation orders should be issued for certain species (e.g. double crested cormorant) when requested by the USDA as opposed to the issuance of numerous individual depredation permits.