DIRECTION OF MOVEMENT OF TAGGED MALE SNOW CRABS (CHIONOECETES-OPILIO) IN THE SOUTHWESTERN GULF OF ST-LAWRENCE

A total of 7760 Chionoecetes opilio males were marked and released on the bottom at the entrance to Chaleur Bay and near the Iles-de-la-Madeleine in the southwestern Gulf of St. Lawrence in 1986 and 1987. Of this number, 976 individuals, all morphometrically mature, were recovered between 1987 and 1989. The average distance covered was 9.6 km for Chaleur Bay (maximum 47.0 km) and 13.7 km for the Iles-de-la-Madeleine (maximum 89.5 km). Size had no significant effect on distance covered or direction of movement. Individuals released at higher or intermediate bottom depths followed the slope downward. In the Chaleur Bay sector, the crabs at greater depth showed a tendency to move up the slope. Near the Iles-de-la-Madeleine, most of the individuals released at greater depth stayed on the valley floor, but there was also a tendency to move upward. It appears that there are two types of travel, a general downward movement, disturbed by seasonal shifts which are undoubtedly related to reproduction. Large movements suggest the possible existence of contacts between local substocks.