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LEVASSEUR, M., M.D. KELLER, E. BONNEAU, D. D'AMOURS, W.K. BELLOWS, 1994. Oceanographic basis of a DMS-related Atlantic cod (Gadus morhua) fishery problem : blackberry feed. Can. J. Fish. Aquat. Sci., 51: 881-889 .
FRÉCHET, A., Y. GAGNON, P. SCHWAB, D. D'AMOURS, J.-D. DUTIL, Y. LAMBERT, L. BOURASSA, C. ROLLET, 1994. Revue de l'état du stock de morue du nord du golfe du Saint-Laurent (3Pn, 4RS) en 1993 ; Review of the status of the northern Gulf of St. Lawrence cod stock (3Pn, 4RS) in 1993. MPO, Pêches de l'Atlantique, Document de recherche ; DFO, Atlantic Fisheries, Research document, 94/29, 50 p .
The 1993 fishing season was conducted with many problems. The fishing season started late because of problems linked with enforcement, the fisheries were stopped many times because of small fish. The initial TAC for 1993 of 31,000 t was reduced at the end of August to 18,000 t on the recommendation of the FRCC. This TAC was based on results of last year's assessment and corresponds to a fishery at the F0.1 reference level. Landings for 1993 were of 18,171 t. There are no directed nor sport fisheries on the 3Pn, 4Rs cod stock in 1994. All available indices indicate a large decline in the last year. The mobile gear catch rates drop by 37 % between 1992 and 1993. The population estimates derived from the 1994 January groundfish research vessel survey represent only 51 % of those estimated in 1993. The population estimates from the summer groundfish survey dropped by 65 %. Catch rates from the Index Fishermen declined in certain cases and maintained themselves in others. For the first time, a calibration of SPA was attempted incorporating results from both the summer and winter surveys. The summer survey series is now long enough to be of interest (4 years) and the winter series will be discontinued in 1995. The 3+ population numbers would have gone from 546 million individuals in 1980 to as low as 95 million individuals in 1993 and the biomass of mature fish (7+) in 1993 could be as low as 10,000 t. Because of problems linked with the quality of the research vessel survey information, the calibration with ADAPT produces anomalously high fishing mortalities. The analysis is thus presented for illustrative purposes only and no projections were done. Biomass is expected to be very low.
D'AMOURS, D., 1993. The distribution of cod (Gadus morhua) in relation to temperature and oxygen level in the Gulf of St. Lawrence. Fish. Oceanogr., 2: 24-29 .
SIMARD, P., M. CASTONGUAY, D. D'AMOURS, P. MAGNAN, 1992. Growth comparison between juvenile Atlantic mackerel (Scomber scombrus) from the two spawning groups of the Northwest Atlantic. Can. J. Fish. Aquat. Sci., 49: 2242-2248 .
D'AMOURS, D., F. GRÉGOIRE, 1992. Analytical correction for oversampled Atlantic mackerel (Scomber scombrus) eggs collected with oblique plankton tows. Fish. Bull., 90: 190-196 .
D'AMOURS, D., M. CASTONGUAY, 1992. Spring migration of Atlantic mackerel, Scomber scombrus, in relation to water temperature through Cabot Strait (Gulf of St. Lawrence). Environ. Biol. Fishes, 34: 393-399 .
D'AMOURS, D., 1992. The distribution of cod (Gadus morhua L.) in relation to oxygen level and temperature in the Northern Gulf of St. Lawrence. CAFSAC Res. Doc., 92/84, 15 p .
Bottom temperature and oxygen levels were measured in the Gulf of St. Lawrence during a trawl survey in August and September 1991, within a random stratified sampling scheme. Cumulative relative frequencies of temperature and of oxygen level were computed with consideration of the sampling scheme. Cumulative relative frequencies of temperature x cod abundance and of oxygen x cod abundance were also computed with consideration of the sampling scheme. Comparisons of the cumulative relative frequencies of bottom conditions and bottom conditions x fish abundance suggest that : 1) cod select intermediate values within the temperature range of the area sampled; 2) cod tend to avoid areas where the oxygen level is below 3-4 mg/l.
D'AMOURS, D., 1992. A test of the adaptive value of growth for juvenile (0-group) Atlantic mackerel (Scomber scombrus). Pages 127-131 in Y. De Lafontaine, T. Lambert, G.R. Lilly, W.D. McKone & R.J. Miller (ed.). Juvenile stages : the missing link in fisheries research : report of a workshop. DFO (Can. Tech. Rep. Fish. Aquat. Sci., 1890) .
SINCLAIR, M., M. CHADWICK, D. CLAY, G. CHOUINARD, D. D'AMOURS, A. FRÉCHET, D. GASCON, P. HUDSON, E. LABERGE, T. LAMBERT, B. RANDALL, J. RUNGE, R. TALLMAN, 1991. Report on the Workshop on Fish. Pages 31-45 in J.-C. Therriault (ed.). The Gulf of St. Lawrence : small ocean or big estuary ? Dept. of Fisheries and Oceans (Can. Spec. Publ. Fish. Aquat. Sci., 113) .
SINCLAIR, M., M. CHADWICK, D. CLAY, G. CHOUINARD, D. D'AMOURS, A. FRÉCHET, D. GASCON, P. HUDSON, E. LABERGE, T. LAMBERT, B. RANDALL, J. RUNGE, R. TALLMAN, 1991. Rapport de l'atelier de travail sur les poissons. Pages 31-45 in J.-C. Therriault (éd.). Le golfe du Saint-Laurent : petit océan ou grand estuaire? Ministère des pêches et des océans (Publ. spéc. can. sci. halieut. aquat., 113) .
D'AMOURS, D., J.G. LANDRY, T.C. LAMBERT, 1990. Growth of juvenile (O-group) Atlantic mackerel (Scomber scombrus) in the Gulf of St. Lawrence. Can. J. Fish. Aquat. Sci., 47: 2212-2218 .
D'AMOURS, D., J. LANDRY, 1989. Capture and husbandry of juvenile (0-year) Atlantic mackerel (Scomber scombrus). Can. Tech. Rep. Fish. Aquat. Sci., 1679, 11 p .
Juvenile (0-year) Atlantic mackerel (Scomber scombrus) were captured in August 1988 in the Gulf of St. Lawrence. Early in the month, more fish were captured with a beach seine inside a semi-enclosed tidal pond then from a beach on the open ocean. Juvenile mackerel were also captured in open water with gill-nets later in the month. Some fish were kept alive in a holding tank for at least a month, and fed chopped fish at a rate of ca. 24 % wet body weight/day; the gross efficiency (mass gained/mass consumed) was 31.6 %. The captive fish grew from means of 95 mm and 8 g on August 14, to 144 mm and 29 g on September 4 (fork length and wet body weight, respectively). Quinaldine sulfate was an effective sedative at a concentration of 3 p.p.m. Fish preserved in anhydrous alcohol shrank by 3.9 % and lost 19 % of their wet weight. The condition factor was higher for the detained than for the wild fish, but lengths were similar at corresponding dates. A one-cycle Gompertz curve was fitted to the length data of the captive fish and the parameters were : Loo=186 mm, K=0.053, and to (julian day)=220 (August 7). From extrapolation on the growth curve of the captive fish, date at hatching length was July 11. Given the water temperature prevailing near this date, spawning had occurred 9 days earlier on July 2. Juvenile Atlantic mackerel grow rapidly, are easily caught with simple fishing gears, and support detention well at least up to a length of 145 mm : they are an ideal species for testing various growth related hypotheses.
D'AMOURS, D., 1988. Vertical distribution and abundance of natant harpacticoid copepods on a vegetated tidal flat. Neth. J. Sea Res., 22: 161-170 .
The vertical distribution in the water column of an assemblage of species of harpacticoid copepods was studied on a vegetated tidal flat in the Fraser River estuary, British Columbia. Natant harpacticoids were collected at discrete levels with a sled-sampler made of 5 cylindrical filtering baskets centered respectively at 56, 156, 256, 356 and 456 mm above the sediment surface. Samples were collected bi-weekly from February 11 to May 27 in 1986. The vertical distribution of Zaus aurelii in the water column was roughly pyramidal with a maximum abundance at intermediate sampling levels (156 - 256 mm). The vertical distribution of Harpacticus uniremis was variable : maximum abundance was observed at the lowest or intermediate (156 - 256 mm) sampling levels. The vertical distribution of Tisbe spp. Had exponential characteristics with maximum abundance at the lowest sampling level. The abundance of natant harpacticoids in the water column was computed by integrating their vertical distribution curves. The maximum abundance of Tisbe spp., Zaus aurelii, and Harpacticus uniremis was respectively 10.6, 1.96 and 0.46 individuals per cm2 of bottom area. Recognition of specific localized patterns in the vertical distribution of natant harpacticoids and knowledge of their total abundance could ease investigations of their recognized role in the diet of the juveniles of several fish species.©1988 Elsevier B.V.
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