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Bibliography of the Maurice Lamontagne Institute

Hugo BOURDAGES

ARCHAMBAULT, D., H. BOURDAGES, B. BERNIER, A. FRÉCHET, J. GAUTHIER, F. GRÉGOIRE, J. LAMBERT, L. SAVARD, 2011. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2011 dans l’estuaire et le nord du golfe du Saint-Laurent ; Preliminary results from the groundfish and shrimp multidisciplinary survey in August 2011 in the Estuary and northern Gulf of St. Lawrence. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2011/112, 108 p .

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In 2011, the annual summer survey for the assessment of abundance and distribution of groundfish and shrimp in the Estuary and the northern Gulf of St. Lawrence was conducted from August 1st to 29th onboard the CCGS Teleost. One of the primary objectives was to estimate abundance indices for the main groundfish species (cod, Greenland halibut, Atlantic halibut and redfishes – Sebastes fasciatus and S. mentella -), and for the Northern shrimp, and to identify the spatial distribution and biological characteristics of these species. The two other main objectives of the survey included monitoring the biodiversity of the Estuary and the northern Gulf, and describing oceanographic conditions observed in August for the sampling area. This report describes preliminary results on the catch rates and distribution of 25 taxa, as well as their size frequency distribution. These results were compared with results from the historical survey series that began in 1990, taking into account the equivalency factors used to convert data from the tandem CCGS Alfred Needler-URI to the tandem CCGS Teleost-Campelen. In 2011, the abundance and biomass indices of many species were stable or decreased compared to 2010. In fact, the two redfish species, cod, black dogfish and longfin hake showed index values below their respective means calculated for the comparative period of 1990-2010. Even if Atlantic halibut, witch, thorny skate, hagfish, northern shrimp and snow crab indices decreased from 2010 to 2011, they were comparable or higher than the mean estimated for the 1990-2010 period. Five species (Greenland halibut, white hake, American plaice, capelin and herring) showed an increase for their indices in 2011. Except for white hake, the indices for these species were similar or higher than the 1990-2010 period means. The geographic distributions of catches recorded for the different species in 2011 showed the same pattern as in previous years. Finally, the size distributions ranges determined for each species remains relatively stable for the entire time of the historical series. However, for some species (Greenland halibut, thorny skate, white hake, witch, American plaice, hagfish and northern shrimp), some size classes observed in 2011 were clearly dominant, and their abundance well above the calculated average for the comparative period.

BOURDAGES, H., S. DUBÉ, 2011. Processus consultatif scientifique régional sur l'évaluation de la lompe du golfe du Saint-Laurent (3Pn, 4RST), 14 février 2011, Institut Maurice-Lamontagne ; Regional Science Advisory Process on the Assessment of Lumpfish in the Gulf of St. Lawrence (3Pn, 4RST), February 14, 2011, Maurice Lamontagne Institute. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2011/009, 16 p .

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SAVARD, L., H. BOURDAGES, 2011. Mise à jour de l'estimation de biomasse et d'abondance de la crevette nordique (Pandalus borealis) à partir du relevé de chalutage dans l'estuaire et le nord du golfe du Saint-Laurent en 2010 ; Update of the estimation of northern shrimp (Pandalus borealis) biomass and abundance from the trawl survey in the Estuary and the northern Gulf of St. Lawrence in 2010. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2011/043, 34 p .

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The Estuary and Gulf of St. Lawrence northern shrimp (Pandalus borealis) stock status is determined every year by examining a number of indicators from the commercial fishery and the research survey. This document presents the data and methods that are used to produce the 2010 survey indicators. The estimates of northern shrimp biomass and abundance are presented for each of the four fishing areas and for each sex.

BOURDAGES, H., J.-F. OUELLET, 2011. Répartition géographique et indices d’abondance des poissons marins du nord du golfe du Saint-Laurent (1990–2009). Rapp. tech. can. sci. halieut. aquat. ; Can. Tech. Rep. Fish. Aquat. Sci., 2963, 171 p .

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The multidisciplinary survey of groundfish and shrimp in the northern Gulf of St. Lawrence has been conducted every August by Fisheries and Oceans Canada for more than two decades. The results of this survey are archived in a database containing information on a variety of georeferenced variables related to the abundance and biological parameters of the taxa caught. This database can be used to analyze the demographics of a wide variety of fish and invertebrate taxa in a spatial and temporal framework. The purpose of this work was to compile the spatial distribution and abundance indicators as well as the biological parameters for fish taxa caught during the survey period. This report presents the results for 115 fish taxa.

BOURDAGES, H., P. GOUDREAU, 2010. Évaluation des stocks de pétoncles des eaux côtières du Québec en 2009. Secrétariat canadien de consultation scientifique Avis scientifique 2010/044 .

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BOURDAGES, H., D. ARCHAMBAULT, D. BERNIER, A. FRECHET, J. GAUTHIER, F. GREGOIRE, J. LAMBERT, L. SAVARD, 2010. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d'août 2009 dans le nord du golfe du Saint-Laurent ; Preliminary results from the groundfish and shrimp multidisciplinary survey in August 2009 in the northern Gulf of St. Lawrence. Rapp. stat. can. sci. halieut. aquat. ; Can. Data Rep. Fish. Aquat. Sci., 1226, 84 p. .

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In 2009, the annual summer survey for the assessment of abundance and distribution of groundfish and shrimp in the northern Gulf of St. Lawrence was conducted from July 31 to August 31 onboard the CCGS Teleost. One of the primary objectives was to estimate abundance indices for the mam groundfish species (particularly cod, Greenland halibut and redfish), and for the Northern shrimp, and to identify the spatial distribution and biological characteristics of these species. Other objectives included monitoring the biodiversity of the nOlthern Gulf and describing oceanographic conditions obser.ved in August. This report describes preliminary results on the catch rate and distribution of 15 taxa, as well as their size frequency distribution. These results were compared with results from the historical survey series that began in 1990, taking into account the equivalency factors used to convert the data from the tandem CCGS Alfred Needler-URI with the tandem CCGS Teleost-Campelen. In 2009, the abundance and biomass indices of many species have decreased compared to the previous years. In fact, the redfish, black dogfish and longfin hake indices are among the lowest values of the series. Greenland halibut, for which indices decreased by about 30 %, shows values similar to the early 2000's. However, the indices observed in 2009 for the other species (cod, Northern shrimp, Atlantic halibut, thorny skate, white hake, American plaice, witch flounder and snow crab) are comparable to the means of the last five years even though a decrease was observed compared to last year. The geographic distributions of catches recorded for the different species in 2009 show the same pattern as we have seen over the previous seven years

BOURDAGES, H., ARCHAMBAULT, D., BERNIER, B., FRECHET, A. GAUTHIER, J. GREGOIRE, F, LAMBERT, J, L. SAVARD, 2010. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2010 dans l’estuaire et le nord du golfe du Saint-Laurent ; Preliminary results from the groundfish and shrimp multidisciplinary survey in August 2010 in the Estuary and northern Gulf of St. Lawrence. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2010/107, 98 p .

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In 2010, the annual summer survey for the assessment of abundance and distribution of groundfish and shrimp in the Estuary and the northern Gulf of St. Lawrence was conducted from August 2nd to September 1st onboard the CCGS Teleost. One of the primary objectives was to estimate abundance indices for the main groundfish species (particularly cod, Greenland halibut, Atlantic halibut and redfishes - fasciatus and mentella-), and for the Northern shrimp, and to identify the spatial distribution and biological characteristics of these species. Other objectives included monitoring the biodiversity of Estuary and the northern Gulf and describing oceanographic conditions observed in August. This report describes preliminary results on the catch rates and distribution of 18 taxa, as well as their size frequency distribution. These results were compared with results from the historical survey series that began in 1990, taking into account the equivalency factors used to convert the data from the tandem CCGS Alfred Needler-URI to the tandem CCGS Teleost-Campelen. In 2010, the abundance and biomass indices of many species were stable or decreased compared to 2009. In fact, the two redfish species (Sebastes fasciatus and S. mentella), cod, black dogfish, white hake and longfin hake show index values below the historical series means. Even if the Northern shrimp and snow crab indices presented a small decrease, they were in the range of the historical series means. Six species (Atlantic Halibut, Greenland Halibut, hagfish, American Plaice, witch, thorny skate) showed an increase for their indices in 2010. Except for Greenland Halibut, the indices for these species were among the highest values of their respective historical series. Besides the fact that no fishing activities took place along the southwestern part of Newfoundland due to mechanical problems, the geographic distributions of catches recorded for the different species in 2010 showed the same pattern as in previous years.

BOURDAGES, H., P. GOUDREAU, 2010. Stock assessment on scallop of the inshore waters of Quebec in 2009. Canadian Science Advisory Secretariat ;Science Advisory Report 2010/044 .

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BOURDAGE, H., P. GOUDREAU, 2010. Évaluation des stocks de pétoncles des eaux côtières du Québec en 2009 : données de la pêche commerciale ; Stock assessment on scallops of the inshore waters of Quebec in 2009: commercial fishery data. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2010/068, viii + 69 p .

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This document presents the commercial fishery index used for the Quebec inshore waters scallops stocks assessment following the 2007-2009 fishing seasons. This review process was held on January 26, 2010 at the Maurice Lamontagne Institute in Mont-Joli. During this meeting, the assembly reviewed the status of the scallop stocks commercially exploited in the Quebec Region. This ocument presents methodologies and data used during the review of the fishery statistics and commercial catches sampling

BRULOTTE, S., B. THOMAS, H. BOURDAGES, M. GIGUERE, M. BOUDREAU, 2010. Captage de naissain de pétoncles sur la rive sud de la Gaspésie (Québec) de 1999 à 2004. Rapp. tech. can. sci. halieut. aquat., 2889, 117 p .

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Efforts have been deployed over the last decade to assess the breeding potential of sea scallops, Placopecten magellanicus, and Iceland scallops, Chlamys islandica, on the south shore of the Gaspé Peninsula. Results from the work performed between 1999 and 2004 concern scallop spat distribution and other related species between the Bay of Tracadigache and the Bay of Gaspé, their distribution in the water column and their available temporal window for collection. In addition, data was collected on the marine environment (temperature and salinity) and the sea scallop’s gonadosomatic development status. Stations were divided into three sectors: Bay of Tracadigache (8 stations), Bay of Gaspé (9 stations) and Centre (7 stations along the coast between Tracadigache and Gaspé). Spat collectors were submerged in late August, early September between 1999 and 2003. They were recovered after being submerged 3, 10, 12, 14 and 22 months. Results revealed that the spawning period for sea scallops appears to occur during the last two weeks of August in the Gaspé Peninsula. Sea and Iceland scallops were captured at every station sampled. Spat collection success for both scallop species was different from one station to another, but was not significantly different from one year to the next. Stations in the Bay of Tracadigache and the Bay of Gaspé had the highest number of captured scallops. The ratio between the abundance of the two scallop species varied based on the station and year. However, in many cases, sea scallops dominated in Tracadigache and sometimes in Gaspé. Spat abundance in the collectors decreased with their soak time. Significant attrition occurred in the Bay of Tracadigache between 3 and 10 months of soak time. A drop in the number of sea scallop specimens was also observed between 10 and 14 months of soak time in all sectors. These losses are likely the result of scallops releasing from the collectors and their predation. Furthermore, the intensity of the annual spat collection does not seem consistent with the depth of the collectors in the water column or with the thermocline, even if in some cases the trends observed appear to support this theory. The peak of settlement for spat scallops occurred at mid-October. Scallop growth varied according to the species, location and year. It was faster for sea scallops than Iceland scallops and faster in the Centre and Gaspé sectors than in Tracadigache. Fouling often covered the collectors, but their abundance fluctuated over time and based on the sector. A wide range of species was found in the collectors, around 40 taxa. The dominant species were Hiatella arctica, Mytilus spp. and hydrozoans. Predators, such as Asterias rubens, Cancer irroratus and Hyas spp. were observed in the collectors. Starfish were the most abundant predator. The available window for most of these species coincided with that of the scallops.

SAVARD, L., H. BOURDAGES, 2010. Estimation de la biomasse et de l’abondance de la crevette nordique Pandalus borealis à partir du relevé de chalutage annuel dans l’estuaire et le nord du golfe du Saint-Laurent entre 1990 et 2009 ; Estimation of northern shrimp Pandalus borealis biomass and abundance from the annual trawl survey in the Estuary and the northern Gulf of St. Lawrence from 1990 to 2009. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2010/061, 51 p .

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The Estuary and Gulf of St. Lawrence northern shrimp Pandalus borealis) stock status is determined every year by examining a number of indicators from the commercial fishery and the research survey. This document presents the data and methods that are used to produce the survey indicators. The estimates of northern shrimp biomass and abundance for the twenty years of the survey (1990-2009) are presented for each of the four fishing areas and for each sex.

MORISSETTE, L., M. CASTONGUAY, C. SAVENKOFF, D.P. SWAIN, D. CHABOT, H. BOURDAGES, M.O. HAMMILL, J. MARK HANSON, 2009. Contrasting changes between the northern and southern Gulf of St. Lawrence ecosystems associated with the collapse of groundfish stocks. Deep-Sea Res., Part II, Top. Stud. Oceanogr., 56(21-22): 2117-2131 .

In order to have a global view of ecosystem changes associated with the collapse of groundfish species in the Gulf of St.Lawrence during the early 1990s, Ecopath mass balance models were constructed in corporating uncertainty in the input data.These models covered two ecosystems (northern and southern Gulf of St.Lawrence; NAFO divisions 4RSand 4T), and two time periods (before the collapse, in the mid-1980s, and after it, in the mid 1990s). Our analyses revealed that the ecosystem structure shifted dramatically from one previously dominated by piscivorous groundfish and small-bodied forage species during the mid-1980s to one now dominated only by small-bodied pelagic species during the mid-1990s in both southern and northern Gulf.The species structure in the northern Gulf versus southern Gulf was different, which may explain why these two ecosystems did not recover the same way from the collapse in the early1990s. Productivity declined in the northern Gulf after the collapse but increased in the southern Gulf. The collapse of groundfish stocks resulted in declines in the mean trophic level of the landings in both the northern and the southern Gulf. Even though fishing mortality was then intentionally reduced, this part of the total mortality was taken up by predation.The temporal changes in the internal structure of both ecosystems are reflected in their overall emergent properties.©2009 Elsevier Ltd.

BOURDAGES, H., 2009. Évaluation des stocks de crevette du golfe et de l’estuaire du Saint-Laurent, 27 et 28 janvier 2009 Institut Maurice-Lamontagne ; Stock assessments on Northern Shrimp in the Estuary and Gulf of St. Lawrence, January 27th and 28th, 2009 Maurice Lamontagne Institute. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2009/013, 22 p .

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This document contains the proceeding from the meeting held within the regional assessment process on Northern shrimp in the Estuary and Gulf of St. Lawrence following the 2008 fishing season. This review process was held on January 27th and 28th, 2009 at the Maurice Lamontagne Institute in Mont-Joli. This meeting gathered more than forty participants from sciences to management to industry. During this meeting, the assembly reviewed the status of the Northern shrimp stocks commercially exploited in the Quebec Region. Therefore, this proceeding contains the essential parts of the presentations and discussions held and relates the main recommendations and conclusions that were presented during the review.

BOURDAGES, H., 2009. Évaluation des stocks de mactre de Stimpson des eaux côtières du Québec en 2008. MPO, Secrétariat canadien de consultation scientifique, Avis scientifique, 2009/021, 8 p .

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BOURDAGES, H., D. ARCHAMBAULT, B. BERNIER, A. FRÉCHET, J. GAUTHIER, F. GRÉGOIRE, J. LAMBERT, L. SAVARD, 2008. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d’août 2007 dans le nord du golfe du Saint-Laurent ; Preliminary results from the groundfish and shrimp multidisciplinary survey from August 2007 in the northern Gulf of St. Lawrence. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2008/046, 77 p .

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In 2007, the annual summer survey for the assessment of abundance and distribution of groundfish and shrimp in the Quebec region was conducted from August 3rd to September 1st in the estuary and northern Gulf of St. Lawrence on board the CCGS Teleost. One of its primary objectives was to estimate abundance indices for the main groundfish species, including the three species targeted by the survey (cod, Greenland halibut, redfish) and Northern shrimp (also targeted by the survey), identify spatial distribution and their biological characteristics. Among the other objectives, the survey aimed at providing a concurrent portrait of environmental conditions in the Gulf for 7 of the Gulf’s 8 geographic regions considered in the assessment of the Gulf’s physical conditions. This report describes for 14 species the preliminary results for catch rate and distribution, as well as their size frequency distribution. These results were compared with the results from the historical survey series introduced in 1990, taking into account the equivalency factors used to convert the data from the tandem CCGS Alfred Needler-URI with the tandem CCGS Teleost-Campelen. None of the species showed much variation compared with the two previous years, except for Atlantic halibut with a still increasing abundance index in 2007. The geographic distribution of catches recorded for the different species in 2007 can be compared to the five previous years. In 2007, the temperatures recorded for surface waters and for the cold intermediate layer (CIL) were generally colder for the entire covered area compared with the temperatures recorded in 2006. The layers <1°C and <0°C of the CIL were much thicker in 2007 than in 2006. However, the temperatures recorded for deep water (300+m) were similar during these two years. Concentrations of dissolved oxygen in the Estuary waters were still considered hypoxic in 2007.

CYR, C. (éd.), H. BOURDAGES (éd.), GAGNÉ, J.A. (président), 2008. Évaluations de l'oursin vert de la Côte-Nord de l'estuaire du Saint-Laurent en 2008, 16 octobre 2008, Institut Maurice-Lamontagne ; Assessments of the green sea urchin stock of north shore of the St. Lawrence estuary in 2008, October 16 2008, Maurice Lamontagne Institute. MPO, Secrétariat canadien de consultation scientifique, Série des comptes rendus ; DFO, Canadian Science Advisory Secretariat, Proceedings Series, 2008/026, 16 p .

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This document contains the proceedings from the meeting held within the regional assessment process to review the status of the Green Sea Urchin stock of the north shore of the St. Lawrence estuary following the 2008 fishing season. The meeting was held on October 16, 2008 at the Maurice Lamontagne Institute in Mont-Joli. During this meeting, the assembly reviewed the stock status of the green sea urchin commercially along the North Shore as well as some environmental conditions that prevailed during the last fishing seasons. Therefore, these proceedings contain the essential parts of the presentations and discussions and relate the main recommendations and conclusions that were presented during the review.

BOURDAGES, H., D. ARCHAMBAULT, B. BERNIER, A. FRÉCHET, J. GAUTHIER, F. GRÉGOIRE, J. LAMBERT, L. SAVARD, 2008. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d'août 2008 dans le nord du golfe du Saint-Laurent ; Preliminary results from the groundfish and shrimp multidisciplinary survey from August 2007 in the northern Gulf of St. Lawrence. Rapp. stat. can. sci. halieut. aquat. ; Can. Data Rep. Fish. Aquat. Sci., 1210, 84 p. .

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In 2008, the annual summer survey for the assessment of abundance and distribution of groundfish and shrimp in the northern Gulf of St. Lawrence was conducted from July 24th to August 25th onboard the CCGS Teleost. One of the primary objectives was to estimate abundance indices for the principal groundfish species, including the three fish species targeted by the survey (cod, Greenland halibut and redfish), and for the Northern shrimp, identify for each of them their spatial distribution and biological characteristics. One of the other objectives, the survey aimed at providing a concurrent portrait of environmental conditions observed in August in the Gulf. This report describes for 14 species the preliminary results for their catch rate and distribution, as well as their size frequency distribution. These results were compared with results from the historical survey series that began in 1990, taking into account the equivalency factors used to convert the data from the tandem CCGS Alfred Needler-URI with the tandem CCGS Teleost-Campelen. While the biomass index in 2008 is still increasing for Atlantic halibut, the indices obtained for the other species are comparable to the means of the last three years. The geographic distributions of catches recorded for the different species in 2008 show the same pattern as for the five previous years.

MORISSETTE, L., M. CASTONGUAY, C. SAVENKOFF, D.P. SWAIN, D. CHABOT, H. BOURDAGES, M.O. HAMMILL, J.M.HANSON, 2008. Contrasting changes between the northern and southern Gulf of St. Lawrence ecosystems associated with the collapse of groundfish stocks. Deep-Sea Res., Part II , Top. Stud. Oceanogr. [ARTICLE IN PRESS] .

In order to have a global view of ecosystem changes associated with the collapse of groundfish species in the Gulf of St. Lawrence during the early 1990s, Ecopath mass-balance models were constructed incorporating uncertainty in the input data. These models covered two ecosystems (northern and southern Gulf of St. Lawrence; NAFO divisions 4RS and 4T), and two time periods (before the collapse, in the mid-1980s, and after it, in the mid-1990s). Our analyses revealed that the ecosystem structure shifted dramatically from one previously dominated by piscivorous groundfish and small-bodied forage species during the mid-1980s to one now dominated only by small-bodied pelagic species during the mid-1990s in both southern and northern Gulf. The species structure in the northern Gulf versus southern Gulf was different, which may explain why these two ecosystems did not recover the same way from the collapse in the early 1990s. Productivity declined in the northern Gulf after the collapse but increased in the southern Gulf. The collapse of groundfish stocks resulted in declines in the mean trophic level of the landings in both the northern and the southern Gulf. Even though fishing mortality was then intentionally reduced, this part of the total mortality was taken up by predation. The temporal changes in the internal structure of both ecosystems are reflected in their overall emergent properties. ©2008 Elsevier Ltd.

SAVENKOFF, C., M. CASTONGUAY, D. CHABOT, M. O. HAMMILL, H. BOURDAGES, L. MORISSETTE, 2007. Changes in the northern Gulf of St. Lawrence ecosystem estimated by inverse modelling : evidence of a fishery-induced regime shift?. Estuar. Coast. Shelf Sci., 73(3-4): 711-724 .

Mass-balance models have been constructed using inverse methodology for the northern Gulf of St. Lawrence for the mid-1980s, the mid-1990s, and the early 2000s to describe ecosystem structure, trophic group interactions, and the effects of fishing and predation on the ecosystem for each time period. Our analyses indicate that the ecosystem structure shifted dramatically from one previously dominated by demersal (cod, redfish) and small-bodied forage (e.g., capelin, mackerel, herring, shrimp) species to one now dominated by small-bodied forage species. Overfishing removed a functional group in the late 1980s, large piscivorous fish (primarily cod and redfish), which has not recovered 14 years after the cessation of heavy fishing. This has left only marine mammals as top predators during the mid-1990s, and marine mammals and small Greenland halibut during the early 2000s. Predation by marine mammals on fish increased from the mid-1980s to the early 2000s while predation by large fish on fish decreased. Capelin and shrimp, the main prey in each period, showed an increase in biomass over the three periods. A switch in the main predators of capelin from cod to marine mammals occurred, while Greenland halibut progressively replaced cod as shrimp predators. Overfishing influenced community structure directly through preferential removal of larger-bodied fishes and indirectly through predation release because larger-bodied fishes exerted top-down control upon other community species or competed with other species for the same prey. Our modelling estimates showed that a change in predation structure or flows at the top of the trophic system led to changes in predation at all lower trophic levels in the northern Gulf of St. Lawrence. These changes represent a case of fishery-induced regime shift. ©2007 Elsevier Ltd.

BOURDAGES, H., 2007. Évaluation des stocks de pétoncles des eaux côtières du Québec en 2006. MPO, Secrétariat canadien de consultation scientifique, Avis scientifique, 2007/015, 21 p .

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BOURDAGES, H., L. SAVARD, D. ARCHAMBAULT, S. VALOIS, 2007. Résultats des expériences de pêche comparative d'août 2004 et 2005 dans le nord du golfe du Saint-Laurent, entre le NGCC Alfred Needler et le NGCC Teleost ; Results from the August 2004 and 2005 comparative fishing experiments in the northern Gulf of St. Lawrence between the CCGS Alfred Needler and the CCGS Teleost. Rapp. tech. can. sci. halieut. aquat. ; Can. Tech. Rep. Fish. Aquat. Sci., 2750, 57 p .

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[Abstract only available in French]
Un relevé de chalutage de fond pour le poisson de fond et la crevette est réalisé annuellement en été dans l’estuaire et le nord du golfe du Saint-Laurent. De 1990 à 2003, le relevé a été réalisé à partir du navire NGCC Alfred Needler équipé d’un chalut à crevette URI 81’/114’. Depuis 2004, le navire NGCC Teleost équipé d’un chalut à crevette Campelen a remplacé le NGCC Alfred Needler et est maintenant utilisé pour réaliser le relevé. Les navires et les chaluts étant passablement différents, il a été convenu que des expériences de pêche comparative seraient réalisées en 2004 et 2005 afin d’être en mesure d’estimer la différence de capturabilité entre les deux tandems navire/chalut. Le but de cette étude est d’estimer la correction qui doit être appliquée aux captures du NGCC Alfred Needler pour les rendre équivalentes à celles qui auraient été faites dans les mêmes conditions sur le NGCC Teleost. Dans tous les cas où le tandem navire/chalut a eu un effet significatif sur la capturabilité des espèces, les captures du NGCC Teleost étaient supérieures à celles du NGCC Needler. La capturabilité relative est positive et supérieure à 1 dans tous les cas, que les captures soient exprimées en nombre ou en poids. Les analyses statistiques ont démontré que les captures des espèces de poissons et d’invertébrés examinées sont influencées différemment par le changement de navire et de chalut. La correction à apporter aux captures est spécifique à chaque espèce et est basée sur le modèle statistique qui décrit le mieux l’effet des covariables sur la capturabilité.

FRÉCHET, A., J. GAUTHIER, P. SCHWAB, H. BOURDAGES, C. TOURNOIS, J. SPINGLE, M. WAY, F. COLLIER, 2007. L’état du stock de morue du nord du golfe du Saint-Laurent (3Pn, 4RS) en 2006 ; The status of cod in the Northern Gulf of St. Lawrence (3Pn, 4RS) in 2006. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2007/068, 89 p .

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The commercial landings for the Northern Gulf of St. Lawrence (3Pn, 4RS) have reached a maximum of 106,000 tons in 1983 while the spawning biomass has reached a maximum of 378,000 tons in 1983. Afterwards, the stock was reduced to a historic minimum mature biomass of 11,000 tons in 1994. The stock was under moratorium from 1994 to 1996 which allowed for a modest improvement of the mature biomass which was at 26,000 tons at the reopening of the commercial fishery in 1997. Since 1997, the commercial fishery has been conducted by fixed gears only (longlines, gillnets and handlines). Despite the low fishing effort and a second moratorium in 2003, the mature biomass of this stock remains low at only 44,000 t in 2007.

SAVENKOFF, C., D.P. SWAIN, J.M. HANSON, M. CASTONGUAY, M.O. HAMMILL, H. BOURDAGES, L. MORISSETTE, D. CHABOT, 2007. Effects of fishing and predation in a heavily exploited ecosystem : comparing periods before and after the collapse of groundfish in the southern Gulf of St. Lawrence (Canada). Ecol. Model., 204(1-2): 115-128 .

Mass-balance models, using inverse methodology, were applied to the southern Gulf of St. Lawrence for the mid-1980s and the mid-1990s to describe ecosystem structure, trophic group interactions, and the effects of fishing and predation on the ecosystem for periods preceding and following the collapse of groundfish stocks in this area. These models were used to determine how the ecosystem changed, and whether its structure and functioning were affected by the observed changes in key species between the two time periods. Our analyses indicate that the ecosystem structure shifted dramatically from one previously dominated by piscivorous groundfish and small-bodied forage species (e.g., capelin, herring, and shrimp) in similar proportions to one now dominated by small-bodied forage species. Overfishing removed a functional group, large-bodied demersal predators that has not been replaced 12 years after the cessation of heavy fishing, and left marine mammals such as seals and cetacea as top predators of many species (especially fishes) during the mid-1990s. Predation by marine mammals on fish increased from the mid-1980s to the mid-1990s while predation by large fish on fish decreased. A change in the prey of seals from juvenile cod to capelin occurred between the models for the mid-1980s and the mid-1990s consistent with observed shifts in the abundance of the two prey species between the two time periods. These major changes were accompanied by a decrease in total catches and a transition in landings from long-lived and piscivorous groundfish toward planktivorous pelagic fish and invertebrates. ©2007 Elsevier B.V.

CHASSOT, E., A. CASKENETTE, D. DUPLISEA, M. HAMMILL, H. BOURDAGES, Y. LAMBERT, G. STENSON, 2007. A model of predation by harp seals (Phoca groenlandica) on the northern Gulf of St. Lawrence stock of Atlantic cod (Gadus morhua) ; Un modèle de prédation des phoques du Groenland (Phoca groenlandica) sur le stock de morue (Gadus morhua) du nord du golfe du Saint-Laurent. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2007/066, 56 p .

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A dynamic model was developed to examine harp seal predation on Atlantic cod in the northern Gulf of St. Lawrence. The model describes the energetic requirements of the seal population by accounting for sex, age-structure and seal growth. The linkage between seals and cod is modeled through a functional response (FR) that was derived from the reconstruction of the seal diet using morphometric relationships and a large database of seal stomach contents. The FR then allows us to quantify the impact of seal predation on the cod population, based on age-structure attack rates and accounting for changes in cod size-at-age with time. Cod recruitment (age 1) is modeled via a linear stock-recruitment relationship based on total egg production that accounts for changes in female length at maturity and cod condition. Natural mortality other than seal predation also depends on cod condition used as an integrative index of changes in environmental conditions. The model was fitted following a maximum likelihood estimation approach to a consistent time-series of abundance indices taking into account changes in DFO research vessels over the last 23 years (1984-2006). Results were consistent with the most recent DFO stock assessment of the northern Gulf of St. Lawrence cod stock, explaining the history of the stock. Predation mortality, despite an increase in the mid-1990s, was a minor proportion of total mortality for ages targeted by harp seals, i.e. ages 1-4. Total cod biomass removed by seals showed higher interannual variability and greater decrease in the early 2000s than for modeling approaches based on a constant ratio diet. The type of FR–II or III– has a strong impact on the biomass removed, especially when the cod abundance is low. Sensitivity analyses were performed to assess the robustness of the results. The next step will be to project the model in to the future to evaluate repercussions of predation mortality rates on cod recovery.

BOURDAGES, H., 2007. Stock assessment on scallops of the inshore waters of Quebec in 2006. DFO, Canadian Science Advisory Secretariat, Science Advisory Report, 2007/015, 21 p .

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BOURDAGES, H., 2007. Assessment of the stimpson's surfclam stocks of Quebec coastal waters in 2008. DFO, Canadian Science Advisory Secretariat, Science Advisory Report, 2009/021, 8 p .

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SÉVIGNY, J.-M., R. MÉTHOT, H. BOURDAGES, D. POWER, P. COMEAU, 2007. Review of the structure, the abundance and distribution of Sebastes mentella and S. fasciatus in Atlantic Canada in a species-at-risk context: an update ; Revue de la structure, de l’abondance et de la distribution de Sebastes mentella et S. fasciatus dans le Canada atlantique dans le contexte des espèces en péril : mise à jour. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2007/085, 109 p .

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This document presents the information reviewed and analyzed by Fisheries and Oceans (DFO) that can be used by the Committee on Status of Endangered Wildlife in Canada (COSEWIC) in assessing status and extinction risk of the two main redfish species (Sebastes fasciatus and S. mentella) in the Northwest Atlantic. Redfish population structure was evaluated in the context of Evolutionarily Significant Units (ESU). The review did not provide evidence of the existence of ESUs within current management units. Therefore, all the analyses were carried out on the actual unit stocks. Methods developed to separate redfish by genotype (for Unit 1-3) or meristics (for NAFO Divisions 2GHJ3KLMNO) were applied to the research vessel survey data to obtain abundance indices. Three distribution indices were calculated: the area of occupancy, the minimum area occupied by 95 % of the stock, and the Gini index of aggregation. No general pattern or trend in geographic distribution was evident. The Unit 1 stock experienced a substantial decline at the beginning of the 1990 and has not recovered yet. However, a new year-class (2003), which seems to be quite important, was observed since the 2005 survey. The stock in NAFO Divisions 2GHJ 3K experienced declines but has shown some signs of recovery. The redfish stocks in remaining management units have not shown signs of decline or the information available for these stocks may not reflect the abundance. Fishery and/or the lack of recruitment were considered the main causes of abundance decline for the stocks in Unit 1 and in NAFO Div. 2GHJ 3K. However, environmental changes and elevated natural mortality were also identified as possible causes of decline. Mature population abundance indices of all redfish stocks in Atlantic Canada are at from one to three orders of magnitude greater than the COSEWIC threshold of 10 000 mature individuals.

BOURDAGES, H., 2006. Assessment of Quebec coastal waters Stimpson's surfclam stocks in 2005. DFO, Canadian Science Advisory Secretariat, Science Advisory Report, 2006/002, 8 p .

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BOURDAGES, H., 2006. Évaluation des stocks de mactre de Stimpson des eaux cotières du Québec en 2005. MPO, Secrétariat canadien de consultation scientifique, Avis scientifique, 2006/002, 8 p .

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BOURDAGES, H., 2005. Stock assessment report on scallops of the inshore waters of Quebec in 2004. DFO, Canadian Science Advisory Secretariat, Science Advisory Report, 2005/031, 19 p .

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BOURDAGES, H., 2005. Évaluation des stocks de pétoncles des eaux côtières du Québec en 2004. MPO, Secrétariat canadien de consultation scientifique, Avis scientifique, 2005/031, 20 p .

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SAVENKOFF, C., H. BOURDAGES, M. CASTONGUAY, L. MORISSETTE, D. CHABOT, M. HAMMILL, 2004. Input data and parameter estimates for ecosystem models of the northern Gulf of St. Lawrence (mid-1990s). Can. Tech. Rep. Fish. Aquat. Sci., 2531, 93 p .

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In the present study, we use Ecopath and inverse methods to reconstruct trophic flows through the whole northern Gulf of St. Lawrence ecosystem (NAFO zones 4RS) for the mid-1990s period, prior to the groundfish stock collapse. This was a period of relatively constant biomass for the major species. The whole-system model of the northern Gulf of St. Lawrence is divided into 32 functional groups or compartments from phytoplankton and detritus to marine mammals and seabirds, including harvested species of pelagic, demersal, and benthic domains. We present here details of the input data (biomass, production, consumption, export, and diet composition) for each compartment used for modelling. the successful development of ecosystem models proposed by the Comparative Dynamics of Exploited Ecosystems in the Northwest Atlantic (CDEENA) program will provide powerful new tools to evaluate the impact of human and environmental factors on a variety of Atlantic shelf ecosystems.

SAVENKOFF, C., H. BOURDAGES, D.P. SWAIN, S.-P. DESPATIE, J.M. HANSON, R. MÉTHOT, L. MORISSETTE, M.O. HAMMILL, 2004. Input data and parameter estimates for ecosystem models of the southern Gulf of St. Lawrence (mid-1980s and 1990s). Can. Tech. Rep. Fish. Aquat. Sci., 2529, 105 p .

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In the present study, we use Ecopath and inverse methods to reconstruct trophic flows through the whole northern Gulf of St. Lawrence ecosystem (NAFO zones 4RS) for the mid-1990s period, prior to the groundfish stock collapse. This was a period of relatively constant biomass for the major species. The whole-system model of the northern Gulf of St. Lawrence is divided into 32 functional groups or compartments from phytoplankton and detritus to marine mammals and seabirds, including harvested species of pelagic, demersal, and benthic domains. We present here details of the input data (biomass, production, consumption, export, and diet composition) for each compartment used for modelling. the successful development of ecosystem models proposed by the Comparative Dynamics of Exploited Ecosystems in the Northwest Atlantic (CDEENA) program will provide powerful new tools to evaluate the impact of human and environmental factors on a variety of Atlantic shelf ecosystems.

BOURDAGES, H., 2004. Pétoncles des eaux côtières de la Côte-Nord du Québec en 2003. Rapport sur l'état des stocks, 2004/021, 11 p .

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BOURDAGES, H., 2004. Scallops of the inshore waters of Quebec's North Shore in 2003. Science, Stock Status Report, 2004/021, 10 p .

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BOURDAGES, H., D. ARCHAMBAULT, B. MORIN, A. FRÉCHET, L. SAVARD, F. GRÉGOIRE, R. DUFOUR, 2004. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d'août 2004 dans le nord du golfe du Saint-Laurent ; Preliminary results from the groundfish and shrimp multidisciplinary survey from August 2004 in the northern Gulf of St. Lawrence. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2004/112, 40 p .

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As a result of the delays in putting the CCGS Alfred Needler into operation, the August 2004 multidisciplinary groundfish and shrimp survey in the northern Gulf of St. Lawrence was conducted aboard the CCGS Teleost, which itself suffered major damage, delaying the start of the mission. The survey was conducted between August 15 and September 2, corresponding to a period that was just over half of the time initially planned. A total of 130 tows were made throughout the area, 95 % of which were successful. Summary findings for catch rates, catch rate distributions and size frequency distributions are presented for 14 species, including the 4 species targeted by the survey (cod, Greenland halibut, redfish and Northern shrimp). However, the 2004 findings are preliminary and must be considered as such until laboratory analyses and data validation have been completed. With the exception of data on the spatial distribution of catches, data obtained during this survey cannot be compared with data obtained during previous missions aboard the CCGS Alfred Needler until conversion indices for each species will be calculated using data obtained during comparative missions. Data gathered in 2004 on the catch distribution of the various species indicate a pattern similar to those observed in previous years aboard the CCGS Alfred Needler.

HAMMILL, M.O., V. LESAGE, J.-F. GOSSELIN, H. BOURDAGES, B. DE MARCH, M.C.S. KINGSLEY, 2004. Evidence for a Decline in Northern Quebec (Nunavik) Belugas. Arctic, 57(2): 183-195 .

Systematic aerial line-transect surveys of beluga whales, Delphinapterus leucas, were conducted in James Bay, eastern Hudson Bay, and Ungava Bay from 14 August to 3 September 2001. An estimated 7901 (SE = 1744) and 1155 (SE = 507) belugas were present at the surface in the offshore areas of James Bay and Hudson Bay, respectively. An additional 39 animals were observed in estuaries during the coastal survey, resulting in an index estimate of 1194 (SE = 507) in eastern Hudson Bay. No belugas were observed in Ungava Bay. Observations from systematic surveys conducted in 1993 and 2001 were analyzed using both line-transect and strip-transect methods to allow comparisons with the strip-transect survey conducted in 1985. A population model incorporating harvest information and fitted to the aerial survey data indicates that the number of belugas in eastern Hudson Bay has declined by almost half because of high harvest levels. Subsistence harvest levels must be reduced significantly if this population is to recover.©2004 The Arctic Institute of North America

FRECHET, A., J. GAUTHIER, P. SCHWAB, H. BOURDAGES, D. CHABOT, F. COLLIER, F. GRÉGOIRE, Y. LAMBERT, G. MOREAULT, L. PAGEAU, J. SPINGLE, 2003. L'état du stock de morue du Nord du golfe du Saint-Laurent (3Pn, 4RS) en 2002 ; The status of cod in the Northern Gulf of St. Lawrence (3Pn, 4RS) in 2002. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2003/065, 90 p .

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The commercial landings for this stock have reached a maximum of 106,000 tons while the stock had reached its maximum mature biomass of 462,000 tons in 1983. Afterwards, the stock was reduced to a minimum mature biomass of 21,000 tons in 1994. The stock was under moratorium from 1994 to 1996 which allowed for a modest improvement of the mature biomass which was at 58,000 tons at the reopening of the commercial fishery in 1997. Since 1997, the commercial fishery has been conducted by fixed gears only (longlines, gill nets and hand lines). Despite the low fishing effort, the mature biomass remains stable at the same low level as when the fishery was reopened in 1997.

MORISSETTE, L., S.-P. DESPATIE, C. SAVENKOFF, M.O. HAMMIL, H. BOURDAGES, D. CHABOT, 2003. Data gathering and input parameters to construct ecosystem models for the nothern Gulf of St. Lawrence (mid-1980s). Can. Tech. Rep. Fish. Aquat. Sci., 2497, 94 p .

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In the present study, we use Ecopath and inverse methods to reconstruct trophic flows through the whole northern Gulf of St. Lawrence ecosystem (NAFO zones 4RS) for the middle 1980s period, prior to the groundfish stock collapses. This was a period of relatively constant biomass for the major species. The whole-system model of the northern Gulf of St. Lawrence is divided into 32 functional groups or compartments from phytoplankton and detritus to marine mammals and seabirds, including harvested species of pelagic, demersal, and benthic domains. We present here details of the input data (biomass, production, consumption, export and diet composition) for each compartment used for modelling. The successful development of Northwest Atlantic (CDEENA) program will provide powerful new tools to evaluate the impact of human and environmental factors on a variety of Atlantic shelf ecosystems.

GOSSELIN, J.-F., V. LESAGE, M.O. HAMMILL, H. BOURDAGES, 2002. Abundance indices of beluga in James Bay, eastern Hudson Bay and Ungava Bay in summer 2001 ; Indices d'abondance de bélugas dans la baie James, l'est de la baie d'Hudson et la baie d'Ungava durant l'été 2001. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2002/042, 28 p .

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Aerial systematic line transect surveys of beluga whales, Delphinapterus leucas, were conducted in James Bay, eastern Hudson Bay and Ungava Bay from 14 August to 3 September 2001. Coastal surveys were conducted on 28 August in Eastern Hudson Bay, on 4 September in Ungava Bay and on 5 September in Hudson Strait and along the northeastern Hudson Bay coast. An effective strip width of 638 m was estimated from the 717 beluga observed on east-west lines in James Bay (557 beluga) and eastern Hudson Bay(160 beluga). An estimated 7,901 (SE =  1,744) and 1,155 (SE =  507) beluga were present at the surface in the offshore areas of James Bay and Hudson Bay respectively. An additional 39 animals were observed in estuaries during the coastal survey resulting in an index estimate of 1,194 (SE =  507) in eastern Hudson Bay. No beluga were observed in Ungava Bay. Three beluga were observed along the coast near Salluit. Observations from the 1993 and 2001 systematic surveys were analysed using both line transect and strip transect methods to allow comparisons with the strip transect survey conducted in 1985. From 1985 to 2001, the number of beluga summering in James Bay increased fourfold, while numbers in eastern Hudson Bay have declined by almost half.

BOURDAGES, H., V. LESAGE, M.O. HAMMILL, B. DE MARCH, 2002. Impact of harvesting on population trends of beluga in eastern Hudson Bay ; Impact de la chasse sur la tendance de la population de bélugas de l'est de la Baie d'Hudson. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2002/036, 46 p .

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Inuit people from the Nunavik have traditionally harvested beluga along the eastern Hudson Bay (EHB), Hudson Strait and Ungava coasts of northern Quebec. Quotas and other management measures exist since 1986, and are revised periodically. The current management plan and recommendations for harvest levels in the Nunavik region were established in April 2001 based on the best available data, i.e. population size in 1985 and 1993, and harvest statistics from 1974-2000. This study presents different scenarios of past and future harvests, while incorporating new information on beluga abundance in James Bay, EHB, Hudson Strait, and Ungava Bay, genetic composition of the harvests, and harvest statistics from 2001. Harvest statistics indicate that the communities of Nunavik exceed quotas each year. Both a relatively simple model using population estimates, removals and rate of increase, and a more complex model introducing additional variables on stage-specific biological parameters were used to examine the impact of harvesting on the growth of the eastern Hudson Bay beluga population. The two models yielded very similar results. They both indicated a decline in EHB beluga population since 1985, a population size in 2001 of approximately 2045 individuals (2090 vs 2001), and an underreporting of harvests prior to 1995 by a factor of 2.23-2.22. The short- and longer-term impacts of future harvesting on the EHB beluga population were examined under different scenarios. However, the probability of decline on the short-term changed little between a harvest of 0 (48 %) or 150 (56 %) beluga from the EHB stock owing to the uncertainty surrounding the current estimates of population size. However, more certainty of a decline is acquired over time, and the influence of the number of removals per year is revealed more clearly over a longer time period. There is a 70-80 % certainty of a decline in five or 10 years if over-harvesting practices similar to what was observed in 2001 (i.e. 125-150 EHB beluga) continue in the future. Reducing the quota to 25 beluga results in a 45 % probability of a smaller stock in five years, whereas a complete cessation of EHB beluga harvesting results in a 35-40 % probability that the stock will show now further decline in 5 years. Using minimum population estimates of 1657 and 1423 individuals for EHB beluga for Model 1 and 2, respectively, and a maximum annual rate of increase of 4 %, the potential biological removal (PBR) is 15 individuals, assuming a recovery factor of 0.5 (for a threatened population which is not in decline). The PBR decreases to 9 beluga if this threatened population is assumed to be declining (recovery factor of 0.3), and to 3 beluga if it is considered endangered (recovery factor of 0.1). In contrast with the EHB population, numbers of beluga in James Bay appear to have increased since 1985 to an estimated 10,504 beluga in 2001 (assuming an annual rate of increase of 0.03 to 0.04). The model fitted best the data when it was allowed to optimise the rate of increase. In this scenario, this population grew at a rate of 0.087 and was estimated to number 15,954 beluga in 2001.

SAVARD, L., H. BOUCHARD, H. BOURDAGES, 2002. Évaluation des stocks de crevette (Pandalus Borealis) de l'estuaire et du golfe du Saint-Laurent pour la période 1990-2001 ; Estuary and Gulf of St. Lawrence shrimp (Pandalus Borealis) stock assessment for the 1990-2001 period. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2002/068, 90 p .

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Overall, the research survey indices show that the shrimp biomass was very high in 2000 and diminished in 2001, moving closer to the mean observed during the 1990-1999 period. Abundance of females decreased in 2001 but is comparable to observations in 1998 and 1999. Not all individuals of the 1997 year-class appear to have changed sex in spring 2001: a certain proportion has remained male. Commercial catch rates were slightly down in the Sept-Îles and Anticosti areas in 2001, but still above the mean for 1990-1999. Exploitation rate indices rose, but are comparable to the mean for 1990-1999. The 2002 fishery will mainly involve the 1997 and 1998 year-classes. The 1997 year-class, which seemed very abundant in commercial and survey catches in 1999 and 2000, produced no substantial increase in commercial catch rates and biomass estimates in 2001. Many individuals remained male in 2001 and should be available to the fishery as females in 2002. However, those that changed sex in 2001 have produced smaller females. The 1998 year-class was weakly represented in the survey and commercial fishery catches, and so no substantial increase in the fishery and survey indices is expected in 2002. Males from the 1999 year-class were a strong presence in fishery and survey catches in 2001. However, they will not change sex and should not contribute to any significant increase in the size of the shrimp taken in 2002.

GRÉGOIRE, F., H. BOURDAGES, J. ROY, 2002. Production d'un indice de dispersion pour le capelan (Mallotus villosus L.) de l'estuaire et du nord du golfe du Saint-Laurent par le krigeage d'indicatrice. Rapp. tech. can. sci. halieut. aquat., 2418, 21 p .

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An index measuring the dispersion of capelin (Mallotus villosus L.) in the Estuary and Gulf of St. Lawrence was produced with indicator kriging. This index was calculated using the capelin catch data (kg/set) from the CCGV Alfred Needler groundfish and shrip (Pandalus borealis) research surveys that took place between 1990 and 2000. Data were transformed into a binary indicator function of capelin presence and absence. The spatial structure of this function was defined with variograms and the corresponding kriged values were used to calculate the minimal probabilities of finding capelin in a specific position. The proposed dispersion index was defined as the total sampled surface associated with a minimal presence probability of 50 %. Since 1990, this index has shown an increasing trend as has that of the percentage of occurance index, which is the current dispersion measurement used to capelin. However, a better delimitation of the dispersion zone was obtained with the indicator kriging because the calculation of this zone was based on the spatial structure of the catches.

BOURDAGES, H., D. ARCHAMBAULT, B. MORIN, A. FRÉCHET, L. SAVARD, F. GRÉGOIRE, M. BÉRUBÉ, 2002. Résultats préliminaires du relevé multidisciplinaire de poissons de fond et de crevette d'août 2002 dans le nord du golfe du Saint-Laurent ;. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2002/090, 69 p .

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In 2002, the groundfish and shrimp multidisciplinary survey in the northern Gulf took place between August 1st and September 1st. A total of 207 fishing tows were conducted over the entire area of which 190 were successful, which corresponds to 76 % of the initial objective of 250 tows. Summary results concerning biomass and abundance, length frequencies and distribution of catch rates are presented for 13 species, including the four that are targeted by the survey (cod, Greenland halibut, redfish and shrimp). Results from 2002 are compared with those from previous years in order to have an indication of the trends for the 13 years time series. However results from 2002 are preliminary and must be considered as such pending laboratory analysis and completion of the validation of data. According to these preliminary results, biomass indices for cod, redfish, witch flounder and American plaice are very low in the northern Gulf while those of shrimp and Greenland halibut have remained high. A general decline in catches is observed for the majority of species along the West Coast of Newfoundland. However, the coverage of this area in 2002 was restricted due to frequent gear damage.

PELLETIER, L., H. BOURDAGES, S. BRULOTTE, 2001. Estimation de la perte de poids subie par l'oursin vert (Strongylocentrotus droebachiensis) suivant sa sortie de l'eau et comparaison de deux techniques de mesure du diamètre du test. Rapp. can. ind. sci. halieut. aquat., 264, 14 p .

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An evaluation of the weight loss by green sea urchins during storage was carried out in response to requests by the working group on green sea urchins and the urchin fishing industry of Quebec. A laboratory experiment using sea urchins from our wetlab facilities allowed us to evaluate the weight loss over six days following the removal of sea urchins from the water and subsequent cold-room storage at 4 degreeC. The weight loss varied in relation to the storage period and the initial weight. The daily average weight losses, expressed as percentages of the initial weight, were rather stable over the experiment (from 0 to 144 hours). For sea urchins of commercial size (test diameter greater than or equal 50 mm), the weight losses after 24, 48, 72, and 144 hours of storage were estimated to be approximately 2, 5, 7, and 14 % of the initial weight of the urchin when it was removed from the water. Feeding of sea urchins prior to removal had no effect on the observed weight loss. In addition, two techniques for measuring the test diameter using a vernier caliper was compared. A fast measurement gave results comparable to those obtained when special care was taken to the exact positioning of the calipers on the opposite ambulacral and interambulacral plates.

MORIN, B., B. BERNIER, H. BOURDAGES, D. BERNIER, R. CAMIRAND, 2001. L'état du stock de sébaste de l'unité 1 (golfe du Saint-Laurent) en 2000 ; The status of the redfish stock in unit 1 (Gulf of St. Lawrence) in 2000. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2001/001, 73 p .

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The fishery in management unit 1 [divisions 4RST +  3Pn and 4Vn (Jan.-May)] has been closed since 1995. Before the fishery was closed, the catch was dominated by fish born in the early 1970s and around 1980. Both groups consisted of the species Sebastes mentella. The abundance of the 1988 year-class, composed mainly of S. fasciatus, has decreased rapidly since 1991. The reasons for the small size of the current stock are heavy past exploitation and lack of recruitment. Following the 1995 closure of the fishery, the stock’s abundance seems to have stabilized; the abundance index derived from DFO’s research surveys has been stable, if low. Two cohorts of juveniles were observed in DFO’s 2000 research survey: the 1996 and 1998 year-classes. Most of these redfish are S. fasciatus, and both of these yearclasses seem relatively weak compared with that of 1988. The catch rate index obtained from the Groundfish Enterprise Allocation Council (GEAC) grid surveys trended downward from 1998 to 2000. The catch per unit effort (CPUE) figures from the index fishery were similar in 1999 and 2000, but lower than those obtained before the fishery was closed in 1995. The indices from the sentinel fishery surveys have also been stable for the period 1995-1999, but the value from the summer 2000 survey amounts to only about half of the 1999 estimate. Overall, the outlook for this stock remains poor for the foreseeable future.

BÉRUBÉ, M., H. BOURDAGES, A. FRÉCHET, 2000. Effects of soak time on catch per unit effort using longline and gillnets for the Northern Gulf of St. Lawrence cod stock ; Effets du temps d'immersion sur les prises par unité d'effort des filets maillants et de la palangre pour le stock de morue du nord du golfe du Saint-Laurent. DFO, Canadian Stock Assessment Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2000/150, 28 p .

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In the case of Northern Gulf cod, the catch per unit effort (CPUE) values for gillnets and longlines under the Sentinel Fisheries Program are used as a complementary index to the abundance assessment. The aim of this study was to determine the effect of soak time on the CPUE for these gear types. The data used came from the results of the Sentinel Fisheries Program between 1995 and 1999, and from ‘Index Fishermen's Program for the 1990 -1993 period. We have endeavoured to provide a more current picture of a potential significant link between the soak time and the catch per unit effort by drawing a trend curve, and by performing non-linear regressions on aggregated data. Subsequently, by using a multiplicative model of variance, we tested the integration of the soak time in the model and the effect of data suppression on the model. We concluded that, since none of these methods showed that soak time is a significant factor, the CPUE values do not have to be adjusted, nor does this variable need to be included in the models to correct for differences in soak time.