BEHAVIORAL-RESPONSES OF RED KING CRAB TO CRAB POTS

High bycatch of female and sublegal sized male king crabs in the fishe ry is of concern to fishermen and management agencies; the efficiency of gear currently used in the fishery needs to be improved. This study examined behavioural responses of red king crabs to pots under labora tory conditions with time-lapse video. Crabs approached the pot from d ownstream, 82% of searches were confined to within 135 degrees of the downstream direction, and 78.3% of crabs searched less than 90 degrees before leaving or entering. The probability of entry success increase d with the number of approaches. Crabs which failed to enter made an a verage of 2.6 approaches compared with 3.9 approaches for crabs which entered pots. The entry success rate was 8.1%. No significant differen ces in approach, search, and entry were found between ovigerous female s, juvenile females, legal-sized males, and sublegal-sized males. Lega l males (greater than or equal to 178 mm carapace width) had a signifi cantly lower escape attempt rate and escape rate than sublegal males a nd females. Crabs depend on chemical cues during foraging, approaching , and searching. The current king crab pot is inefficient because crab s have difficulties in accessing the entrances and non-legal crabs hav e difficulties in escaping. (C) 1997 Elsevier Science B.V.