Determination of the Area Prospected by a Baited Trap from a Tagging and Recapture Experiment with Snow Crabs ( Chionoecetes opilio )

Abstract

The area of influence of a baited trap of the type used in the southwestern Gulf of St. Lawrence snow crab fishery was studied by releasing tagged crabs at increasing distances from the bait and noting recaptures after fishing periods of 24 and 48 hr. For the shorter fishing period, the recapture rate decreased with increasing distance of released crabs from the trap. The radius of the prospected area was estimated to be in the range of 100-140m, with the radius of the effected fished area being about 50-70m. Results from the 48-hr experiment were inconclusive. The low recapture rates (maximum 5%) and the long distances travelled by the tagged crabs (up to 3,000 m in 48 hr) lead to the belief that biological factors, inasmuch as they interfere with the simple bait stimulus-response mechanism, play an important role in variation of catch success. The results of this study also indicated that the trap's influence extends over a greater area than has been suggested in previous studies.