The Effectiveness Of A Halibut Excluder Device And Consideration Of Tradeoffs In Its Application.

Though the commercial value per pound of Pacific halibut (Hippoglossus stenolepis) is greater than that of most target species in trawl fisheries off Alaska, halibut retention is prohibited for trawlers and individual groundfish target trawl fisheries are subject to closure if they attain either their seasonal or annual limit of allowed halibut bycatch mortality. Although all groundfish fisheries catch considerable amounts of halibut as bycatch, only longline fishermen holding quota share in the individual fishing quota (IFQ) program are allowed to retain halibut in the federally managed fisheries off Alaska. To avoid catching halibut, trawl fishermen voluntarily developed a rigid grate system and escape panel which are installed ahead of the trawl “codend”. The bycatch reduction device was then formally tested by an industry trade association in conjunction with a National Marine Fisheries Service (NMFS) fishing gear researcher under an Experimental Fishing Permit in 1998. Results from the experiment showed the device excluded 94 % of the halibut while only releasing 38 % of the target flatfish. Linear simulations of the fishery were developed to estimate the potential benefit of the grate. Results indicated that fleet-wide use of the grate would result in a 171 % increase in the duration of the fishery, a 61 % increase in target flatfish catch, and a 71 % reduction in overall halibut bycatch. Other simulations demonstrated a high incentive for individual noncompliance. Factors affecting incentives for voluntary or regulatory use of bycatch reduction devices are explored in detail within the context of the highly regulated flatfish fisheries under federal management off Alaska.