AFSC/RACE/MACE: Bycatch Reduction: halibut excluder for pelagic and bottom trawls

Conservation Engineering scientists work cooperatively with Alaska fishing industry partners, gear manufacturers, and the trawl fleet to design and test gear modifications such as excluder devices to exclude halibut from trawls because current halibut bycatch levels have the potential to shut down the target fisheries. This work has been happening on and off since the mid 1990’s depending on the halibut stock assessment and if halibut bycatch is an issue with the North Pacific Fisheries Management Council. This work has typically been done as specific experimental tests or research projects on board chartered commercial fishing vessels or in “ride along” situations while the vessel is commercially fishing.

Halibut bycatch in the Alaska trawl fisheries has been an issue for 40 years with cycles of increased importance based on how abundant the halibut stock is. Most recently halibut populations in the North Pacific are being closely watched due to shrinking size at age. Additionally, in 2013 the International Pacific Halibut Commission (IPHC) cut the target fishery Total Allowable Catch (TAC) by 11% in the Bering Sea for 2014 and continued to reduce the TAC for 2015. The 2015 TAC for the directed halibut fishery was lower than the allowable bycatch allocation for the combined trawl fleets. This created the need for the North Pacific Fisheries Management Council (NPFMC) to reduce the halibut bycatch allocation or Prohibited Species Catch (PSC) by 25% for the Amendment 80 fleet and 15% for the Bering Sea/Aleutian Islands (BSAI) limited access trawl fishery. The Conservation Engineering group has been working cooperatively with the Alaska fishing industry partners, gear manufacturer’s and the trawl fleet to create and test trawl gear modifications such as halibut excluders to reduce bycatch. Testing of such devices requires using camera and sonar equipment to collect visual imagery of how the halibut excluder device is working, e.g. configuration of the fishing gear and the excluder device and fish behavior in relation to the device. Fishing depth and temperature are typically collected as well.

These data were collected in accordance NOAA protocols for fisheries acoustics surveys and related sampling (Alaska Fisheries Science Center), 23 p. Prepared by Midwater Assessment and Conservation Engineering Program, Alaska Fish. Sci. Center, Natl. Mar. Fish. Serv., NOAA. Available online: http://www.afsc.noaa.gov/RACE/midwater/AFSC%20AT%20Survey%20Protocols_Feb%202013.pdf