Growth Estimation of Male Dungeness Crabs in Southeastern Alaska Based on Tagging Data

The commercial Dungeness crab (Cancer magister) fishery in southeastern Alaska has seen an annual production averaging 1588 t over the last 30 years. The fishery is passively managed with regulations governing size, sex, and season, or “3-S” management. Regulations include a minimum size of 6.5-inches (165 mm) notch-to-notch carapace width (CW), male-only harvest, and a split summer (June 15–August 15) and fall (October 1–November 30) season for most areas. The size limit is supposed to provide males with the opportunity to mate for a full year before recruiting to the fishery. Combined with the provision for male-only harvest, this is intended to protect the reproductive potential of the stock. The current tagging program was designed to expand the geographic basis and sample size of growth information in order to examine the appropriateness of the current size limit. We use the completed tag-recapture data from 2000–2004 tagging experiments at seven different locations in southeastern Alaska (Peril Strait, Tenakee Inlet, Port Camden, Duncan Canal, Stikine River Flats, Berners Bay, and St. James Bay) to establish a logistic molt probability and a linear growth increment model. There were 6744 tagged crab releases with 1814 (27%) recaptures.  Previous analyses with incomplete recovery data suggested that molt increment and probability remained similar to that observed in the 1970s, but new comparisons will be made with the results of the complete data series.