Mortality Threats to Birds - Gill Nets

Northern Gannet by Alan Wilson

Northern Gannet by Alan Wilson

The Problem

From mid-November 2002 through January 2003, hundreds of dead and dying seabirds washed up along the North Carolina shore, believed by biologists to be victims of shallow-set fishing nets. More than 300 birds including Brown Pelicans, Double-crested Cormorants, and Northern Gannets were found on a number of beaches, including Cape Lookout National Seashore, an ABC-designated Globally Important Bird Area. This incident was just one more in the ongoing problem of waterbird bycatch from gill and other fishing nets, such as those used in the Mid-Atlantic for shad and in the Pacific for salmon. Birds dive down to catch fish trapped in the nets, become entangled in the nylon mesh and drown.

 

Gill nets account for less than 0.5% of fish caught nationally. Yet the fishery is responsible for the annual deaths of thousands of Red-throated Loons off the Atlantic Coast, tens of thousands of Marbled Murrelets off the shores of Alaska and British Columbia, and thousands of other birds.

 

The problem of avian gill net bycatch has been well known for years, yet little has been done to rectify the situation. Since a February 1999 U.S. Fish and Wildlife Service (FWS) study, which revealed the extent of the gill net problem, conservationists have been frustrated by the slow pace of action by federal authorities to prevent these continuing violations of the Migratory Bird Treaty Act (MBTA). FWS assembled a Waterbird Bycatch Working Group in 1999 to develop a national plan of action to reduce the threat, but other than the production of a short policy statement, little has been done. A draft action plan has languished in FWS subcommittee for more than a year and a half, and no timeline has been forthcoming to bring it to completion.

Conservationists fear that the plan will be as weak as the policy statement and will only present voluntary guidelines and best-practice suggestions, without mandating measures to ensure bycatch is eliminated. No prosecutions for violations of the MBTA have been brought even within the FWS’s three mile zone of enforcement. FWS officials cite a lack of resources to pursue cases.

The Solution

Recent studies by the Washington Sea Grant Program have shown some simple measures can reduce avian mortality without drastically impacting fishing efficiency. Ed Melvin and colleagues found that by replacing the top six feet of the normally hard-to-see green nylon mesh gill nets with a more visible white mesh, bycatch of Common Murre in salmon nets could be decreased by 45% without significantly reducing fish catches. Further research is necessary to test the effectiveness of this and other possible solutions in other fisheries.