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Bibliography of the Maurice Lamontagne Institute

Dominique GASCON

GASCON, D., SONIA DUBÉ, 2010. Compte rendu du processus de consultation scientifique zonal sur le sébaste des unités 1 et 2, 25 et 26 février 2010, Institut Maurice-Lamontagne ; Proceedings of the zonal advisory process for Redfish in Units 1 & 2, February 25th and 26th, 2010, Maurice Lamontagne Institute. DFO, Canadian Science Advisory Secretariat, Proceedings Series ; MPO, Secrétariat canadien de consultation scientifique, Série des compte rendus 2010/018, 28 p .

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CYR, C., D. GASCON, 2008. Évaluations des stocks de crevette et de crabe des neiges de la région du Québec suivant la saison de pêche 2007, du 4 au 12 février 2008, Institut Maurice-Lamontagne ; Northern shrimp and snow crab stock assessments of the 2007 fishing season in the Quebec Region, February 4 to 12, 2008, Maurice Lamontagne Institute. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2008/020, 48 p .

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This document contains the proceedings of the stocks assessment meetings made within the framework of the regional stock assessment process of the Quebec region following the 2007 fishing season. This advisory process was carried out from February 4 to 6 for the snow crab stocks and February 12, 2008 for the Northern shrimp stocks at the Maurice-Lamontagne Institute, Mont-Joli. During these meetings, the stock status of these two species commercially exploited in the Estuary and the Gulf of St. Lawrence, and some of the environmental parameters prevailing at the time of the 2007 fishing season were reviewed. These proceedings document the major points presented and discussed during the meetings and also present the principal recommendations and conclusions that were made at the time of the review.

CYR, C., D. GASCON, 2008. Évaluations des stocks de poisson de fonds de la région du Québec suivant la saison de pêche 2007, du 25 au 29 février 2008, Institut Maurice-Lamontagne ; Regional groundfish stock assessments of the 2007 fishing season in the Quebec Region, February 25 to 29, 2008, Maurice Lamontagne Institute. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2008/019, 53 p .

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Ce document renferme les comptes rendus des réunions d’évaluation des stocks tenues dans le cadre du processus régional d’évaluation des stocks de la région du Québec suite à la saison de pêche 2007. Ce processus de revue s’est déroulé du 25 au 29 février 2008 à l’Institut Maurice-Lamontagne, à Mont-Joli. Lors de ces rencontres, l’assemblée a revu l’état de plusieurs stocks de poisson de fond exploités commercialement dans l’estuaire et le golfe du Saint-Laurent ainsi que certains paramètres environnementaux qui prévalaient lors du déroulement de la saison de pêche 2007. Ces comptes rendus contiennent donc l’essentiel des présentations et des discussions tenues et font état des principales recommandations et conclusions émises au moment de la revue.

CYR, C., D. GASCON, 2008. Évaluations des stocks de crustacés de la région du Québec suivant la saison de pêche 2005, 24 janvier au 2 février, 2006, Institut Maurice-Lamontagne ; Regional crustaceans stock assessments of the 2005 fishing season in the Quebec Region, January 24 to February 2, 2006, Maurice Lamontagne Institute. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2008/006, 53 p .

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This document contains the proceedings from the different meetings held within the regional assessment process on crustaceans stocks in the Quebec Region following the 2005 fishing season. This review process was held from January 24 to February 2, 2006 at the Maurice Lamontagne Institute in Mont-Joli. During these meetings, the assembly reviewed the status of several stocks commercially exploited in the Estuary and Gulf of St. Lawrence as well as certain environmental parameters that prevailed during the 2005 fishing season. Therefore, these proceedings contain the essential parts of the presentations and discussions held and relate the main recommendations and conclusions that were presented during the review.

CYR, C., D. GASCON, 2007. Évaluations des stocks de poissons pélagiques de la région du Québec suivant la saison de pêche 2005, 4 et 5 avril 2006, Institut Maurice-Lamontagne ; Regional pelagic stock assessments of the 2005 fishing season in the Quebec Region, April 4-5, 2006, Maurice Lamontagne Institute. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2007/058, 26 p .

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This document contains the proceedings from the different meetings held within the regional assessment process on pelagic fish stocks in the Quebec Region following the 2005 fishing season. This review process was held on April 4-5, 2006 at the Maurice Lamontagne Institute in Mont-Joli. During these meetings, the assembly reviewed the status of several marine species stocks commercially exploited in the Estuary and Gulf of St. Lawrence as well as certain environmental parameters that prevailed during the 2005 fishing season. Therefore, these proceedings contain the essential parts of the presentations and discussions held and relate the main recommendations and conclusions that were presented during the review.

CYR, C., D. GASCON, 2007. Évaluations des stocks de poisson de fonds de la région du Québec suivant la saison de pêche 2005, du 6 au 10 février 2006, Institut Maurice-Lamontagne ; Regional groundfish stock assessments of the 2005 fishing season in the Quebec Region, February 6-10, 2006, Maurice Lamontagne Instittue. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2007/054, 32 p .

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This document contains the proceedings of the meetings made within the framework of the regional stock assessment process of the Quebec region following the 2005 fishing season. This advisory process was carried out from February 6 - 10, 2006 at the Maurice-Lamontagne Institute, Mont-Joli. During these meetings, the stock status of several marine species commercially exploited in the Estuary and the Gulf of St. Lawrence, and some of the environmental parameters prevailing at the time of the 2005 fishing season were reviewed. These proceedings document the major points presented and discussed during the meetings and also present the principal recommendations and conclusions that were made at the time of the review.

CYR, C., D. GASCON, 2007. Évaluations des stocks de la région du Québec suivant la saison de pêche 2006, du 23 janvier au 23 février 2007, Institut Maurice-Lamontagne ; Regional stock assessments of the 2006 fishing season in the Quebec Region, from January 23 to February 23 2007, Maurice Lamontagne Institute. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2007/046, 79 p .

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This document contains the proceedings of the meetings made within the framework of the regional stock assessment process of the Quebec region following the 2006 fishing season. This advisory process was carried out from January 23 to February 23, 2007 at the Maurice-Lamontagne Institute, Mont-Joli. During these meetings, the stock status of several marine species commercially exploited in the Estuary and the Gulf of St. Lawrence, and some of the environmental parameters prevailing at the time of the 2006 fishing season were reviewed. These proceedings document the major points presented and discussed during the meetings and also present the principal recommendations and conclusions that were made at the time of the review.

CHADWICK, E.M.P., W. BRODIE, E. COLBOURNE, D. CLARK, D. GASCON, T. HURLBUT, 2007. History of annual multi-species trawl surveys on the Atlantic coast of Canada;Historique des relevés de chalut multi-spécifiques annuels sur la côte Atlantique du Canada. AZMP Bull. PMZA, 6: 25-42 .

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The department of Fisheries and Oceans has conducted annual multi-species fisheries surveys for nearly four decades in the four Atlantic coast regions to provide an assessment of the state of marine resources and environmental conditions throughout the major shelf areas of eastern Canada. Over the years, there have been significant modifications to survey design, vessels, gear type, tow speed, time of survey, biological sampling protocols, and oceanographic observations. An awareness of these changes is essential to interpret the data properly.

GASCON, D., B. SAINTE-MARIE, 2006. Examination of industry trawl survey of April 2006 in relation to the assessment of the snow crab in CFA 16. DFO, Canadian Science Advisory Secretariat, Science Advisory Report, 2006/026, 6 p .

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GASCON, D., B. SAINTE-MARIE, 2006. Examen du relevé au chalut de l'industrie d'avril 2006 dans le contexte de l'évaluation du crabe des neiges de la zone 16. MPO, Secrétariat canadien de consultation scientifique, Avis scientifique, 2006/026, 6 p .

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DUTIL, J.-D., R. MILLER, C. NOZÈRES, B. BERNIER, D. BERNIER, D. GASCON, 2006. Révision des identifications de poissons faites lors des relevés scientifiques annuels de l'abondance des poissons de fond et de la crevette nordique dans l'estuaire et le nord du golfe du Saint-Laurent. Rapp. manus. can. sci. halieut. aquat., 2760, 87 p .

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Long time series of data are a source of invaluable information to put a current situation in a historical perspective. The data obtained from the scientific research surveys for the assessment of demersal fish and northern shrimp abundance conducted annually in the estuary and northern Gulf of St. Lawrence are regularly used for this purpose. The validity of these data is not questioned with regard to the identification of commercial species managed by our region, but this overall statement may not apply as well to the identification of non commercial fish species. Following a workshop held at IML in 2005, a working group has determined whether the data on the identification of non commercial species and commercial species not being managed by our region and collected between 1978 and 2003 are valid. For these species, the sampling protocol varied markedly over time. Not all fish were identified to the species level and in many instances very broad taxonomic levels were used. The identification of some species was inadequate, particularly in the Cottidae, Liparidae and Zoarcidae families. Overall, this data set must be used with caution if one is interested in the rare species, in measuring biodiversity, or in studying the temporal trends in the case of the species which are not managed by our region. In this report, we identify the weaknesses and suggest solutions to improve quality in the historical data as well as in the process of acquisition of new data.

CYR, C., S. GOSSELIN, D. GASCON, 2005. Évaluation des stocks de la région du Québec suivant la saison de pêche, du 14 décembre 2004 au 17 février 2005, Institut Maurice-Lamontagne ; Regional stock assessments of the 2004 fishing season in the Québec Region. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2005/030, 97 p .

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This document contains the proceedings of the meetings made within the framework of the regional stock assessment process of the Quebec region following the 2004 fishing season. This advisory process was carried out from December 14, 2004 to February 17, 2005 at the Maurice-Lamontagne Institute, Mont-Joli. During these meetings, the stock status of several marine species commercially exploited in the Estuary and the Gulf of St. Lawrence, and some of the environmental parameters prevailing at the time of the 2004 fishing season were reviewed. These proceedings document the major points presented and discussed during the meetings and also present the principal recommendations and conclusions that were made at the time of the review.

GASCON, D. (éd.), 2003. Redfish Multidisciplinary Research Zonal Program (1995-1998) : Final Report. Can. Tech. Rep. Fish. Aquat. Sci., 2462, 152 p .

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This report provides under the form of extended abstracts the main results of the Redfish Multidisciplinary Research Program (1995-1999) which sought to examine aspects of the biology and fisheries of redfish to develop a better understanding of these species in order to insure long term economic viability and sustainability of the fishery. The program was divided into four main components: 1) Species identification and stock structure; 2) Improved stock assessment and management approaches; 3) Distribution in relation to enbroad consultation with the redfish fishing industry and the results presented to them at a final workshop held in Novembre 1999.

GASCON, D. (éd.), 2003. Programme de recherche multidisciplinaire sur le sébaste (1995-1998) : rapport final. Rapp. tech. can. sci. halieut. aquat., 2462, 152 p .

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This report provides under the form of extended abstracts the main results of the Redfish Multidisciplinary Research Program (1995-1999)_which sought to examine aspects of the biology and fisheries of redfish to develop a better understanding of these species in order to insure long term economic viability and sustainability of the fishery. The program was divided into four main components: 1) Species identification and stock structure; 2) improved stock assessment and management approaches; 3) distirbution in relation to environmental conditions; and 4) recruitment studies. These objectives were established in a broad consultation with the redfish fishing industry and the results presented to them at a final workshop held in November 1999.

DUTIL, J.-D., M. CASTONGUAY, D. GILBERT, D. GASCON, 2002. Production analyses for cold-water and warm-water stocks and their use to predict surplus production. Pages 50-54 in N. Anderson, G. Ottersen & D. Swain (ed.). Report of the ICES/GLOBEC Workshop on the Dynamics of Growth in Cod. International Council for the Exploration of the Sea (ICES Coop. Res. Rep., 252 .

Surplus and net production per capita became nil or negative in the mid-1980s in the northern Gulf of St. Lawrence (Dutil et al., 1999). This situation was partly explained by a marked decline in growth production and is consistent with smaller sizes-at-age (Chouinard and Fréchet 1994) but also lower condition factor values during the same period (Lambert and Dutil 1997). The nutritional condition of cod in the Gulf of St. Lawrence varies markedly both seasonnally and annually (Lambert and Dutil 1997, Schwalme and Chouinard 1999) and this has been found to be associated with changes in swimming capacity (unpublished data), reproductive investment (Lambertet al., 2000, Lambert and Dutil 2000) and risks of natural mortality (Dutil and Lambert 2000; and unpublished data). Positive slopes between size-at-age and temperature suggested faster growth rates at higher temperatures for northern Gulf cod, but correlations between size-at-age and temperature were not significant (Dutil et al., 1999). Production analyses conducted for the northern Gulf of St. Lawrence were extended to other stocks. Growth production was assessed in order to determine its variability among and within stocks as a first step to measure its impact on the stock biomass.©2008 ICES

DUTIL, J.-D., M. CASTONGUAY, D. GILBERT, D. GASCON, 2000. Production analyses for cold-water and warm-water stocks and their use to predict surplus production. Pages 61-65 in N.G. Andersen, G. Ottersen & D.P. Swain (ed.). Report of the ICES/GLOBEC workshop on the dynamics of growth in cod, Dartmouth, Canada, 8-10 May 2000 (ICES C.M., 2000/C:12) .

DUTIL, J.-D., M. CASTONGUAY, D. GILBERT, D. GASCON, 1999. Growth, condition, and environmental relationships in Atlantic cod (Gadus morhua) in the northern Gulf of St. Lawrence and implications for management strategies in the Northwest Atlantic. Can. J. Fish. Aquat. Sci., 56(10): 1818-1831 .

Northern Gulf of St. Lawrence Atlantic cod (Gadus morhua) is one of several stocks that collapsed in eastern Canada following a long period of intensive exploitation. Surplus and net production per capita became nil or negative in the mid-1980s so that any level of exploitation would have caused a decline of the stock. This was partly explained by a marked decline in growth production and is consistent with smaller sizes-at-age but also lower condition factor values during the same period. Correlations between size-at-age and temperature were not significant when corrected for autocorrelation, but slopes were always positive, suggesting higher growth rates at higher temperatures. Smaller sizes-at-age in the 1980s were not associated with changes in the fishery or increased fishing mortality, nor were they consistent with the density-dependence hypothesis. Lengths at age 8 decreased by more than 10 cm as the stock decreased 10-fold in abundance. While size-at-age and temperature covary in cod when all stocks are examined, size-temperature relationships are not as clear if the analysis is restricted to cold-water stocks, possibly because of differences in food availability. Biological production varies from year to year and among stocks and should be taken into consideration when managing fisheries in variable or extreme environments.

DUTIL, J.-D., M. CASTONGUAY, M.O. HAMMILL, P. OUELLET, Y. LAMBERT, D. CHABOT, H. BROWMAN, D. GILBERT, A. FRÉCHET, J.-A. GAGNÉ, D. GASCON, L. SAVARD, 1998. Environmental influences on the productivity of cod stocks : some evidence for the northern Gulf of St. Lawrence, and required changes in management practices. DFO, Canadian Stock Assessment Secretariat, Research Document, 98/18, 42 p .

GASCON, D., R. O'BOYLE, 1998. Gulf of St. Lawrence marine fisheries overview. Science, Stock Status Report, G1-01, 13 p .

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GASCON, D., R. O'BOYLE, 1998. Aperçu des pêches marines du golfe du Saint-Laurent. Rapport sur l'état des stocks, G1-01, 16 p .

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CHOUINARD, G., D. GASCON, M. HAMMILL, 1996. Aperçu sur les pêches du golfe du Saint-Laurent. MPO, Pêches de l'Atlantique, Rapport sur l'état des stocks, 96/50, 9 p .

GASCON, D., 1996. The black dogfish in the Gulf of St. Lawrence. DFO, Atlantic Fisheries, Stock Status Report, 96/61, 4 p .

CHOUINARD, G., D. GASCON, M. HAMMILL, 1996. Gulf of St. Lawrence fisheries overview. DFO, Atlantic Fisheries, Stock Status Report, 96/50, 8 p .

GASCON, D., 1996. L'aiguillat noir dans le golfe du Saint-Laurent. MPO, Pêches de l'Atlantique, Rapport sur l'état des stocks, 96/61, 4 p .

GASCON, D. (éd.), 1995. Compilation des rapports sur l'état des stocks en 1994 : stocks de poissons du golfe du Saint-Laurent évalués par la région des Laurentides en 1995. Rapp. manus. can. sci. halieut. aquat., 2335, 89 p .

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The present document is a compilation of eight stock status reports that describe important results and main conclusions pertaining to the conservation and management of seven fish stocks from the Gulf of Saint-laurence, and to the environmental conditions in the Gulf of Saint-Laurence in 1994. These reports represent biological input to the Fisheries Resources Conservation Council and fisheries managers which allows them to formulate advice on conservation and to draw management plans for these resources. The stock included in this report are : herring in the northern Gulf of St. Lawrence, capelin in the Gulf, cod in the northern Gulf, Greenland halibut in the Gulf, Atlantic halibut in the Gulf, redfish in the Gulf, and finally mackerel in the northwest Atlantic.

GASCON, D. (éd.), 1995. Collected stock status reports for 1994 : fish stocks in the Gulf of Saint-Lawrence assessed by the Laurentian Region in 1995. Can. Manuscr. Rep. Fish. Aquat. Sci., 2335, 89 p .

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The present document is a compilation of eight stock status reports that describe important results and main conclusions pertaining to the conservation and management of seven fish stocks from the Gulf of Saint-laurence, and to the environmental conditions in the Gulf of Saint-Laurence in 1994. These reports represent biological input to the Fisheries Resources Conservation Council and fisheries managers which allows them to formulate advice on conservation and to draw management plans for these resources. The stock included in this report are : herring in the northern Gulf of St. Lawrence, capelin in the Gulf, cod in the northern Gulf, Greenland halibut in the Gulf, Atlantic halibut in the Gulf, redfish in the Gulf, and finally mackerel in the northwest Atlantic.

GASCON, D. (éd.), 1994. Rapport sur l'état des stocks de poissons pour la région du Québec en 1994 ; Fish stocks status report for the Quebec region in 1994. Rapp. manus. can. sci. halieut. aquat. ; Can. Manuscr. Rep. Fish. Aquat. Sci., 2253, 71 p .

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Fish stock assessments were reviewed regionally for the first time in 1994. This document describes in detail the technical basis for the assessment of fish stocks made at the Maurice Lamontagne Institute in May 1994. The stocks described are : herring on the west coast of Newfoundland (NAFO Division 4R), cod in the northern Gulf of St-Lawrence (NAFO Divisions 3Pn, 4R and 4S), mackerel in the northwest Atlantic (NAFO subareas 2 to 6), redfish in the Gulf of St-Lawrence - Unit 1 (NAFO Divisions 4R, 4S and 4T + 3Pn-4Vn[Jan.-May]), and Greenland halibut in the Gulf (NAFO Divisions 4R, 4S and 4T). Summaries of climatic conditions in the Gulf of St-Lawrence in 1993, and of the status of the main biological components are also included. This report provides the technical descriptions supporting the conclusions on stock status in 1994.

GASCON, D. (éd.), 1994. Fish stocks status report for the Quebec region in 1994. Can. Manuscr. Rep. Fish. Aquat. Sci., 2253, 71 p .

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Fish stock assessments were reviewed regionally for the first time in 1994. This document describes in detail the technical basis for the assessment of fish stocks made at the Maurice Lamontagne Institute in May 1994. The stocks described are : herring on the west coast of Newfoundland (NAFO Division 4R), cod in the northern Gulf of St-Lawrence (NAFO Divisions 3Pn, 4R and 4S), mackerel in the northwest Atlantic (NAFO subareas 2 to 6), redfish in the Gulf of St-Lawrence - Unit 1 (NAFO Divisions 4R, 4S and 4T + 3Pn-4Vn[Jan.-May]), and Greenland halibut in the Gulf (NAFO Divisions 4R, 4S and 4T). Summaries of climatic conditions in the Gulf of St-Lawrence in 1993, and of the status of the main biological components are also included. This report provides the technical descriptions supporting the conclusions on stock status in 1994.

SINCLAIR, A., D. GASCON, R. O'BOYLE, D. RIVARD, S. GAVARIS, 1991. Consistency of some Northwest Atlantic groundfish stock assessments. NAFO Sci. Counc. Stud., 16: 59-77 .

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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) .

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, A., D. GASCON, R. O'BOYLE, D. RIVARD, S. GAVARIS, 1990. Consistency of some Northwest Atlantic groundfish stock assessments. NAFO SCR Doc., 90/96, 35 p .

GASCON, D., M. APARICIO, B. MERCILLE, 1990. Estimations du mélange entre les stocks de morue du Nord du golfe du Saint-Laurent (division 3Pn4RS) et les stocks adjacents (2J3KL, 3Ps et 4TVn (janvier-avril) à partir de résultats de marquage. CSCPCA doc. rech., 90/61, 25 p .

De LAFONTAINE, Y., D. GASCON, 1989. Ontogenetic variation in the vertical distribution of eggs and larvae of Atlantic mackerel (Scomber scombrus). Rapp. P-v. Réun. CIEM, 191: 137-145 .

GASCON, D., 1988. Catch projections. Pages 135-146 in D. Rivard (ed.). Collected papers on stock assessment methods (CAFSAC Res. Doc., 88/61) .

SINCLAIR, M., J.W. LODER, D. GASCON, E.P. HORNE, I. PERRY, E.J. SANDEMAN, 1987. Fisheries needs for physical oceanographic information within the Atlantic zone. Can. Tech. Rep. Fish. Aquat. Sci., 1568, 166 p .

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A working group of fisheries biologists and physical oceanographers of the Department of Fisheries and Oceans was formed in May 1985 to determine fisheries needs for physical oceanographic information in the Atlantic Zone. This report summarizes their findings. A historical sketch summarizes the links between physical oceanography and fisheries biology in the northern Atlantic since the turn of the century. The review indicated that a critical requirement for the definition of fisheries needs for physical oceanographic information is a clear statement of the fisheries research questions themselves. Four categories of fisheries problems were identified : 1) definition of populations, 2) temporal changes in availability of fisheries resources to either commercial fisheries or research surveys, 3) causes of recruitment variability, and 4) long-term changes in abundance levels.The physical oceanographic information that is relevant to each of these categories of fisheries questions is discussed. Recommendations for research within the Department are provided.

LABERGE, E., P.J. RUBEC, D. GASCON, D.B. ATKINSON, 1987. Assessment of 4RST redfish (Sebastes spp.). CAFSAC Res. Doc., 87/64, 45 p .

Reported landings for the NAFO Divisions 4RST redfish fishery in 1986 were estimated at 33,107 t. Although they constitute a 5,000 t increase from last year, they still represent only 60 % of the TAC. Catch rates for bottom trawls (excluding Engels high-lift), Engels high-lift trawls and midwater trawls were analyzed separately using a multiplicative model. The catch rate series shows 2 distinct peaks, one in 1967-1968 (1.33 t/h) and the other in 1981-1982 (1.29 t/h) and have declined since then; the decline appears to have stopped in 1986. Length frequency distributions based on commercial sampling and research survey data show the presence of 2 strong year-classes : one from the early 1970's (fish about 30 cm) and one from the early 1980's (fish about 20 cm). These smaller fish should be recruiting to the fishery in the next few years. The current biomass (beginning of 1987) was estimated from a non-linear version of the Schaefer general production model to be 473,000 t. Because of uncertainties with regard to the changes in availability of fish to the gear, and therefore the effort levels implied, the recommended catch for 1988 were set at the 2/3fmey equilibrium yield of 56,000 t.

GILBERT, M., D. GASCON, 1987. Consommation de crevettes nordiques (Pandalus borealis Kroyer) par la morue (Gadus morhua L.) dans le nord-ouest du golfe du Saint-Laurent. Naturaliste can., 114: 203-209 .

The intensity of predation and size selectivity by cod (Gadus morhua) on northern shrimp (Pandalus borealis) were examined in relation to depth (depth zones of 146-183 m and 183-220 m) in the northwestern Gulf of St. Lawrence. Shrimp is a major component of the cod diet, and its abundance in the stomach contents increases with the size of the predator. However, the size distribution of ingested shrimp did not differ with cod length. Predation is more intense in the deep zone and appears to be more related to prey abundance than to selection of large shrimps by cod.©1987 Université Laval

FRÉCHET, A., D. GASCON, 1986. Une nouvelle matrice de capture à l'âge pour le stock de morue des divisions 4R, 4S et 3Pn. CSCPCA doc. rech., 86/104, 34 p .

The catch-at-age matrix for the cod stock in the northern Gulf of St. Lawrence (Divisions 4R, 4S and 3Pn) was recalculated to separate catches of mobile gears from the catches of fixed gears in order to account for the selectivity of the two gear categories in adjusting sequential population analysis. The procedure used in recalculating the catch-at-age matrix is detailed in this document. The new matrix does not differ substantially from the matrix used in past assessments, but the new matrix agrees more precisely with nominal catch data.

GASCON, D., B. MERCILLE, 1986. Le maquereau (Scomber scombrus Linné) du nord-ouest de l'Atlantique, sous-régions 2 à 6 de l'OPANO. CSCPCA doc. rech., 86/92, 33 p .

Northwest Atlantic mackerel catches have averaged approximately 37 000 t since 1978. These catches are substantially below the 270 000 t average for the previous 10 years. Catches in 1985 greatly increased owing to the expansion of joint ventures between the United States and European countries. The nominal catch for 1985 was 68 000 t. Sequential population analysis (SPA) was run using a terminal fishing mortality of F=0.1. The partial recruitment vector was calculated using SVPA, but the fully recruited age was later lowered to 3 to account for the strong increase in catches by foreign fleets in the winter fishery of 1985. No tuning of SPA was attempted, because of the inadequacies of the abundance indices, and because SPA will not converge for recent years at low fishing mortalities. The level of fishing mortality chosen (F=0.1) is on line with values used in previous years, and population estimates obtained under this assumption agree well with the trends perceived in the abundance of mackerel. Under these assumptions, catch projections at F0.1 for mackerel are 245 000 t in 1986 and 202 000 t in 1987.