AFSC/RACE/MACE: Bycatch reduction: salmon excluder for pelagic trawl

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 salmon from pollock trawls because current salmon bycatch levels have the potential to shut down the pollock fishery. This work has been on-going since 2001. Much of this work has been conducted by the Alaska fishing industry under Exempted Fishing Permits (EFP’s) with some help from the Conservation Engineering (CE) group. Therefore, much of the data collect belongs to the industry. CE’s contribution to this work has typically been done as specific experimental tests or research projects on board chartered commercial fishing vessels, helping to collect the data during the EFP’s or in “ride along” situations while the vessel is commercially fishing.

Salmon bycatch is a critical issue facing one of the largest and most valuable fisheries of the United States, the Alaska pollock fishery. There is a strict cap on the number of salmon that can be taken in the pollock fishery and boats actively avoid fishing in areas where salmon bycatch is a problem. Several tools are being applied to reduce salmon bycatch, including allocation of bycatch at the vessel level by, near-real-time monitoring of bycatch rates, leading to targeted closures and the development of salmon excluders, devices that allow salmon to escape from trawl nets while pollock are retained. Since 2001, the AFSC Conservation Engineering project has collaborated on the development of salmon excluders with United Catcher Boats and the North Pacific Fisheries Research Foundation, with support from several other fishing companies, trawl manufacturers and related organizations. 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.