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Bibliography of the Maurice Lamontagne Institute

Jean-Maurice COUTU

DUFOUR, R., J.-M. COUTU, 1990. État des stocks de crabe des neiges de l'estuaire et du nord du golfe du Saint-Laurent - Évaluation 1989. CSCPCA doc. rech., 90/37, 42 p .

In 1989, the fishery in areas 17 and 16 ended after 11 and 12 weeks respectively because of the poor quality of the captured crabs at the end of the season. The 1989 fishing season lasted only one week in Area 15 for similar reasons. The 1989 spring fishery previously planned in areas 13 and 14 was abandoned due to persisting ice conditions and weak catch rates. However, two fishing periods were allowed in the fall, from August to the end of September, and the season ended in 11 weeks. In addition to this change in areas 14 and 13, individual allocations were half the 1988 level and were set at 18.2 t in 1989. Total landings coming from these stocks have been declining since 1985, and the 1989 captures were 33 % less than that of the 1988 season, ending at 2580 t. The largest decrease, 84 %, came from areas 15, 14, and 13. The landings also diminished to a less extent in the other areas. On the southern shore of area 17, the 1989 mean catch rate calculated from Japanese traps, dropped slightly by 10 % from 1988, but the exploitation rate of 53 % stayed within the CAFSAC recommended threshold of 50 to 60 %. On the other hand, the mean arch rate dropped by 31 % from 1988 on the northern shore. The 1989 fishing season can be considered good in Area 16 compared to that of 1988. Although there was a high occurrence of white crab in June after three months of fishing, the catches were similar to that of 1988 and the mean catch rate per trap increased in all sectors of the area. The exploitation rates calculated in the area were below or within the recommended CAFSAC threshold. The catch rates obtained during the fall portion of the 1989 season showed encouraging signs for next year in most of the sectors. After major changes in their 1989 season and weak yield obtained thereafter, the areas 14 and 13 fishermen reoriented themselves toward other species such as cod in the Black Tickle area. Reasons for this unsuccessful fishing year may be multiple and diverse. The analysis of the fishery and research data showed a possible recruitment failure for 1988. As the 1989 fishing season was similar to that of 1988, we believe that the 1989 recruitment was also at a low level. However, the 1990 fishing season and that of subsequent years may improve substantially in area 13 if the influx of crab forecasted from the 1987-88 tagging surveys enter the fishery. Nevertheless, considering our present knowledge on the growth and the dynamics of this species, no precise long term prediction on the future stock catches can be obtained.

DUFOUR, R., J.-M. COUTU, 1989. Crabe des neiges de l'estuaire et du nord du golfe du Saint-Laurent : évaluation 1988. CSCPCA doc. rech., 89/31, 51 p .

A preliminary estimate of total landings from the snow crab fishery in the Estuary and North Shore of the Gulf of St. Lawrence in 1988 shows a 31 % drop from 1987 levels. This sharp drop affected all zones, on a gradient sloping upward from west to east. In Zone 17, the 4 % decline from 1987 to 1988 may be explained by the appearance in June of large numbers of soft-shell crabs in the catches. Despite a recovery, or at least a halt in the decline, of the yield of Japanese traps on the south shore, yields on the north shore declined slightly in 1988, indicating a decline in production there. A reduction in fishing effort is recommended for Zone 17, through implementation of a preventive quota of less than 1000 t for 1989. In the western and central areas of Zone 16, the yields of Japanese traps are beginning to stabilize, while those of the eastern areas have been declining sharply since 1985, with no sign of recovery in 1988. Exploitation rates are high in the west (0.65) and east (0.68), and very high in Zone 15 (0.86). A major decrease in fishing pressure in Zone 15 and 16 would be desirable, and might possibly permit recovery of catch rates in the eastern part of Zone 16 and continuation of the recovery seen in the central and western areas of the zone. Implementation of a preventive quota lower than 1988 catches in Zones 15 and 15 is recommended. Although the biomass estimates calculated from tagging in 1987 and 1988 in Zone 13 show a bias that is unaccounted for, analysis of the rate of recapture of tags released in 1987 and recaptured in the same proportions in this zone in 1987 and 1988 (0.8 and 1.1 tags/10,000 crabs) indicate low recruitment to the commercial-sized crab stock between the two years. This would explain the sharp drop in catches recorded in 1988. Such as explanation is supported by analysis of the fishery statistics, which shows that the mean yield from the Japanese traps, which are mostly used in this zone, declined by half from 1987 to 1988. Also, the difference between the initial biomasses calculated in 1987 and 1988 by Leslie analysis (1326 t) corresponds quite well with the 1987 landings in the zone (1495 t). Many young male crabs under 75 cm were caught in Zone 13 and 14 during the 1988 tagging operation, pointing to a short-term recovery of the stock. In the meantime, a substantial reduction in fishing effort in the two zones would minimize the possible impact of overexploitation of these stocks.

DUTIL, J.-D., J.-M. COUTU, 1988. Early marine life of Atlantic salmon, Salmo salar, postsmolts in the northern Gulf of St. Lawrence. Fish. Bull., 86: 197-212 .

DUFOUR, R., J.-M. COUTU, 1988. Stocks de crabe des neiges de l'estuaire et du nord du golfe du Saint-Laurent - Évaluation 1987. CSCPCA doc. rech., 88/35, 48 p .

BAILEY, R., J.-M. COUTU, 1987. Crabe des neiges (Chionoecetes opilio) de l'estuaire et du nord du golfe du Saint-Laurent : évaluation de 1986. CSCPCA doc. rech., 87/70, 41 p .