Reducing the Bottom Impact of Alaskan Groundfish Trawls

The impact on the Alaskan Crab resources of groundfish trawls used in the Bering Sea Yellowfin Sole fishery has recentlys become a controversial issue. Excessive crab by-catch and suspected high rates of mortality haye threatened the continuation of this important trawl fishery. To address the problem, scale models of the trawl gear in present use were tested in the 22 foot wide circulating water channel and the 52 foot wide tow tank at the David Taylor Naval Ship R&D Center. This paper describes how these scale model experiments were used to study the effect of trawl design and rigging adjustments on bottom-tending performance. Through the proper selection, rigging, and operation of trawl system components, it was found that sustained contact with the bottom of most portions of the gear can be minimized.