Analysis of Minimum Size Limit for the Red King Crab Fishery in Bristol Bay, Alaska

Abstract

Abstract Low stock status of red king crabs Paralithodes camtschaticus in Bristol Bay prompted an industry initiative to reduce the minimum size limit for the commercial fishery from 165 mm in carapace width (CW) to 152 mm in CW. In terms of carapace length (CL), which is the metric used in data collection programs, this is equivalent to a reduction from 137 to 128 mm CL. The rationale was primarily to reduce potential nontarget handling mortality, which was suspected to contribute to the depressed stock status. Analysis of red king crab fishery observer data showed that the reduced size limit would initially increase catch rates of legals (under new size limit) by 10–41%, diminish total bycatch of nontarget red king crabs (sublegal and female crabs) by 9–33%, and reduce the fishing effort (pot lifts) needed to attain annual catch quotas by 2–27%. Yield-per-recruit analysis indicated that steady-state yield would decline 5–7% under the smaller size limit, assuming a 20% handling mortality rate. Size distr...