Product recovery rates for bled sablefish

Abstract

Accurate catch estimates are necessary for successful fishery management. Catch weights may be affected by fish bleeding; a practice fishermen use to ensure product quality. We conducted field experiments during July 2002 and July 2003 in the Gulf of Alaska to estimate the change in fish weight due to blood loss for sablefish. Fish weights were compared before and after bleeding. Sablefish lost more weight when bled without seawater than when immersed in flowing seawater. Sablefish lost more weight when carefully brought aboard than when gaffed aboard (bled without flowing seawater). Gaffed sablefish lost weight even when not intentionally bled because of blood loss at the gaff wound. The product recovery rate (PRR) currently applied by fishery managers to estimate catch weight for bled sablefish (2.0%) slightly overestimates “blood loss” for fish gaffed aboard (1.7%). The PRR applied by fishery managers for unbled sablefish (0.0%) underestimates “blood loss” for fish gaffed aboard (1.0%). Estimating the actual change in weight due to blood loss for a commercial fishing trip is difficult because it requires accounting for storage methods and handling practices.


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