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Bibliography of the Maurice Lamontagne Institute

Claude SAVENKOFF

BENOÎT, H.P., J.A. GAGNÉ, C. SAVENKOFF, P. OUELLET, M.-N. BOURASSA, 2012. State-of-the-Ocean report for the Gulf of St. Lawrence Integrated Management (GOSLIM) area. Can. Manuscr. Rep. Fish. Aquat. Sci., 2986, 81 p .

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This document is part of an initiative conducted by the Canadian Department of Fisheries and Oceans to report on the ecological "State of the Oceans" (SOTO). It concisely summarizes the most recent scientific information relevant to six key issues that have a considerable impact on the ecosystems of the Estuary and Gulf of St. Lawrence Large Ocean Management Area (LOMA): (1) hypoxia in the deep waters, (2) ocean acidification, (3) changes in seasonal sea-ice cover and its effect on marine mammals, (4) aquatic invasive species, (5) impacts of fishing and climate-driven changes in exploited marine populations and communities, and (6) potential impacts of grey seal predation on groundfish populations. The information is presented following the Drivers Pressures State Impacts and Responses approach (DPSIR) to the identification and management of the environmental effects. Existing reports on the structure, state, and management of the Estuary and Gulf of St. Lawrence LOMA are also reviewed with the aim to highlight the manner in which the present report complements that information. Furthermore, a brief discussion on what should constitute the structure and content of a more effective SOTO report is presented as an explanation for the nature of the present report and as a guide for future SOTO reporting in the LOMA. The report results from a collaboration between ocean scientists and managers in support of integrated management in the St. Lawrence LOMA.

GIGUÈRE, N., P. NELLIS, G.H. TREMBLAY, M. GIANGIOPPI, H.-F. ELLEFSEN, A. MAGASSOUBA, S. COMTOIS, C. SAVENKOFF, R. DUFOUR, 2011. Démarche d’évaluation du risque : développement d’outils et application à la zone de fraie et d’alevinage du capelan. Rapp. tech. can. sci. halieut. aquat., 2947, 45 p .

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This pilot project is linked to current national work and applies the theoretical notions of a risk analysis in the context of a real situation: capelin conservation in the Estuary and Gulf of St. Lawrence. While phase I resulted in the identification and the formulation of the problem through the development of Pathways of Effects (PoE) models, phase II, presented in this report, focusses on the development of a proposed risk assessment procedure and associated tools to be applied. The procedure is composed of four types of analysis: analyses of predicted conditions, measured conditions, and desired conditions, and a comparative analysis of conditions. The human activities and stressors identified in PoE models that potentially affect the capelin spawning / larval retention area were used to develop and apply the tools. To do this, Gallix beach, located in the region of Sept-Îles (Quebec, Canada), was selected as the ecological unit of reference. The proposed risk assessment procedure contributed to the development of a tool to analyze the predicted conditions. To carry out the three remaining types of analysis, other avenues were explored. All in all, the second phase of the pilot project demonstrated that tools can be developed to be versatile, flexible, and to perform well when used in a real context. Lastly, the work confirmed that risk assessment within a risk analysis process can help decision makers define priorities and subsequently focus their efforts on the management and regulation of activities that have greater potential social, cultural, or economic impacts.

GIGUÈRE, N., P. NELLIS, G.H. TREMBLAY, M. GIANGIOPPI, H.-F. ELLEFSEN, A. MAGASSOUBA, S. COMTOIS, C. SAVENKOFF, R.DUFOUR, 2011. Risk assessment procedure : development of tools and application in the capelin spawning. Can. Tech. Rep. Fish. Aquat. Sci.,2947, 44 p .

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This pilot project is linked to current national work and applies the theoretical notions of a risk analysis in the context of a real situation: capelin conservation in the Estuary and Gulf of St. Lawrence. While phase I resulted in the identification and the formulation of the problem through the development of Pathways of Effects (PoE) models, phase II, presented in this report, focusses on the development of a proposed risk assessment procedure and associated tools to be applied. The procedure is composed of four types of analysis: analyses of predicted conditions, measured conditions, and desired conditions, and a comparative analysis of conditions. The human activities and stressors identified in PoE models that potentially affect the capelin spawning / larval retention area were used to develop and apply the tools. To do this, Gallix beach, located in the region of Sept-Îles (Quebec, Canada), was selected as the ecological unit of reference. The proposed risk assessment procedure contributed to the development of a tool to analyze the predicted conditions. To carry out the three remaining types of analysis, other avenues were explored. All in all, the second phase of the pilot project demonstrated that tools can be developed to be versatile, flexible, and to perform well when used in a real context. Lastly, the work confirmed that risk assessment within a risk analysis process can help decision makers define priorities and subsequently focus their efforts on the management and regulation of activities that have greater potential social, cultural, or economic impacts.

GIGUÈRE, N., L. PERREAULT, P. NELLIS, C. SAVENKOFF, F.BILODEAU, M. GIANGIOPPI, G.H. TREMBLAY, R. DUFOUR, S. COMTOIS, F. GRÉGOIRE, 2011. Pathways of effects (PoE) model development for capelin conservation as part of a risk analysis process. Can. Tech. Rep. Fish. Aquat. Sci., 2934, 78 p .

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The purpose of the first phase of this pilot project was to create Pathways of Effects (PoE) models for capelin conservation in the Estuary and Gulf of St. Lawrence as part of a risk analysis process. When conducting this type of analysis, the PoE is created during the identification and problem formulation phase, the goal being to identify the potential relationships that exist between human activities, the stressors generated, and their impacts on a component of the ecosystem, and consequently on the communities that depend on this component. This project is related to the current national work on risk analysis and applies the theoretical notions established in the earlier work in the context of a real situation. In this context, capelin conservation in the Estuary and Gulf of St. Lawrence was identified for this project, since capelin is a key species in the marine food chain. During this phase, six PoE models were developed, each illustrating one view of capelin conservation that is either general or specific. Together, these models serve illustrate the relationships that exist between the ecological, socioeconomic, and cultural components as well as such key ecological parameters as the quantity and quality of capelin spawning / larval retention habitat and capelin abundance. The development and application of PoE models using a real situation have confirmed their usefulness as tools for integrating knowledge and for communication; PoEs also play a role in providing support for decision-making and guidance for subsequent steps in the risk analysis process.

GIGUÈRE, N., L. PERREAULT, P. NELLIS, C. SAVENKOFF, F. BILODEAU, M. GIANGIOPPI, G.H. TREMBLAY, R. DUFOUR, S. COMTOIS, F. GRÉGOIRE, 2011. Réalisation de modèles de séquence des effets (SdE) appliqués à la conservation du capelan dans le cadre d'une approche d'analyse de risque. Rapp. tech. can. sci. halieut. aquat., 2934, 83 p .

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The purpose of the first phase of this pilot project was to create Pathways of Effects (PoE) models for capelin conservation in the Estuary and Gulf of St. Lawrence as part of a risk analysis process. When conducting this type of analysis, the PoE is created during the identification and problem formulation phase, the goal being to identify the potential relationships that exist between human activities, the stressors generated, and their impacts on a component of the ecosystem, and consequently on the communities that depend on this component. This project is related to the current national work on risk analysis and applies the theoretical notions established in the earlier work in the context of a real situation. In this context, capelin conservation in the Estuary and Gulf of St. Lawrence was identified for this project, since capelin is a key species in the marine food chain. During this phase, six PoE models were developed, each illustrating one view of capelin conservation that is either general or specific. Together, these models serve illustrate the relationships that exist between the ecological, socioeconomic, and cultural components as well as such key ecological parameters as the quantity and quality of capelin spawning / larval retention habitat and capelin abundance. The development and application of PoE models using a real situation have confirmed their usefulness as tools for integrating knowledge and for communication; PoEs also play a role in providing support for decision-making and guidance for subsequent steps in the risk analysis process.

BRIGOLIN, D., C. SAVENKOFF, M. ZUCCHETTA, F. PRANOVI, P. FRANZOI, P. TORRICELLI, R. PASTRES, 2011. An inverse model for the analysis of the Venice lagoon food web. Ecol. Model., 222(14): 2404-2413 .

A steady-state model of the Venice lagoon food web was constructed, based on a comprehensive set of data, which were collected in the years 2001–2005. Energy flows were estimated by means of an inverse methodology of constrained optimization based on the Minimum Norm criterion, i.e. on the minimization of both the sum of squares of the residuals and of the sum of squares of energy flows. The solution was constrained by a set inequalities, which were derived from general eco-physiological knowledge and site specific data on energy flows. The trophic network was represented by thirty-two nodes, including singlespecies compartments for the species of high economical or ecological relevance. Mass balance equations were weighted, in order to obtain meaningful results in presence of large differences, up to 5 orders of magnitude, among biomasses. A perturbation technique was applied, with the purpose of reducing the risk of finding solutions heavily affected by the set of constraints and of obtaining a more robust representation of the energy flows. The main patterns of energy flow are consistent with those obtained in previous attempts at modelling the Venice lagoon food web. Micro- and macro-phytobenthos account for the largest fraction of the primary production. Energy is then transferred towards higher trophic levels by means of two main pathways: the recycling of dead biomass through the detritus compartment and the direct consumption by grazers. The first pathway is the most important and accounts for approximately two/thirds of the energy transferred to the second trophic level.©2011 Elsevier B.V.

DUFOUR, R., H. BENOIT, M. CASTONGUAY, J. CHASSÉ, L. DEVINE, P. GALBRAITH, M. HARVEY, P. LAROUCHE, S. LESSARD, B. PETRIE, L. SAVARD, C. SAVENKOFF, L. ST-AMAND, M. STARR, 2010. 2010 Canadian marine ecosystem status and trends report. Advis. Sec. Sci. Advis. Rep. 2010/030(Revised), 38 p .

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DUFOUR, R., H. BENOIT, M. CASTONGUAY, J. CHASSÉ, L. DEVINE, P. GALBRAITH, M. HARVEY, P. LAROUCHE, S. LESSARD, B. PETRIE, L. SAVARD, C. SAVENKOFF, L. ST-AMAND, M. STARR, 2010. Rapport sur l'état et les tendances des écosystèmes marins canadiens en 2010. MPO, Secrétariat canadien de consultation scientifique, Avis scientifique, 2010/030(révisé), 43 p .

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DUFOUR, R., H. BENOIT, M. CASTONGUAY, J. CHASSÉ, L. DEVINE, P. GALBRAITH, M. HARVEY, P. LAROUCHE, S. LESSARD, B. PETRIE, L. SAVARD, C. SAVENKOFF, L. ST-AMAND, M. STARR, 2010. Ecosystem status and trends report: Estuary and Gulf of St. Lawrence ecozone. Rapport sur l’état et les tendances des écosystèmes : écozone de l’estuaire et du golfe du Saint Laurent. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche; 2010/030, 193 p .

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This document was produced under the umbrella of the national ecosystem status and trends report program and deal with the estuary and gulf of St.Lawrence ecozone. It is structured around the status and trends of some important marine species and physico-chemical variables of the ecosystem. The national ecosystem status and trends report will support prioruty-setting for a national biodiversity agenda and will integrate national and provincial exosystem-bases information. It will report on many large terrestrial and marine ecozones.

COMTOIS, S., C. SAVENKOFF, M.-N. BOURASSA, J.-C. BRÊTHES, R. SEARS, 2010. Regional distribution and abundance of Blue and Humpback Whales in the Gulf of St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci., 2877, 46 p .

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Blue whale sightings have been monitored in the Gulf of St. Lawrence (GSL) by the Mingan Island Cetacean Study (MICS) since 1979. More than 400 individuals with a heterogeneous GSL distribution have been identified to date. This report aims to qualitatively describe the distribution, dispersal, and relative abundance of blue whales on temporal and spatial scales. Information gathered on humpback whales is also described. Results confirm the general nomadic behaviour of blue whales and suggest that the GSL represents only a portion of the broad summer feeding range. Results also indicate that individual behaviours on site fidelity vary considerably: occasional vs. regular visitors and cosmopolitan vs. exclusive animals. In addition, we were able to distinguish between several areas of significant blue whale sightings based on temporal trends in the site’s frequentation. While the lower Estuary seems to be the area where blue whales are most often sighted, the Mingan region has seen its blue whale frequentation decrease to such an extent that observations are now rare. Conversely, an increasing number of humpback whales have been observed in the Mingan region each year. Because many questions on their general ecology remain unanswered, the aim of this study was to increase our knowledge on the habitat use and behaviour of these rorquals. Furthermore, since marine mammals have been proposed as ecosystem sentinels, long-term monitoring can detect spatial or temporal trends that could reflect changing processes in the environment

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.

SAVENKOFF, C., S. VALOIS, D. CHABOT, M.O. HAMMILL, 2009. Input data and parameter estimates for ecosystem models of the northern Gulf of St. Lawrence (2003–2005). Can. Tech. Rep. Fish. Aquat. Sci., 2829, 123 p .

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Mass-balance models were used to reconstruct trophic flows through the whole northern Gulf of St. Lawrence ecosystem (NAFO divisions 4RS) for the 2003-2005 period. The whole-system model of the northern Gulf of St. Lawrence is divided into 31 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 parameter estimates from inverse modelling are also shown for comparison.

BUNDY, A., J.J. HEYMANS, L. MORISSETTE, C. SAVENKOFF, 2009. Seals, cod and forage fish: A comparative exploration of variations in the theme of stock collapse and ecosystem change in four Northwest Atlantic ecosystems. Prog. Oceanogr., 81(1-4): 188-206 .

The facts: four Northwest Atlantic ecosystems, three cod stock collapses 15 years ago (plus one severely depleted), seals now top predator in all ecosystems, all had cod as a top predator before collapse, groundfish declines in all areas, forage base increased in most systems. No recovery in any system. Have these ecosystems fundamentally changed? Why? The challenge: compare and contrast these four ecosystems. The answer: using mass balance models, empirical data and a suite of ecosystem indicators, we explore how and why these systems have changed over time. At the ecosystem and community level, we see broad similarities between ecosystems. However, structurally and functionally these systems have shifted to an alternate state, with changes in predator structure, trophic structure and flow.Crown Copyright.©2009 Published by Elsevier Ltd.

DUTIL, J.-D., C. NOZÈRES, P.-M. SCALLON-CHOUINARD, L. VAN GUELPEN, D. BERNIER, S. PROULX, R. MILLER, C. SAVENKOFF, 2009. Poissons connus et méconnus des fonds marins du Saint-Laurent. Naturaliste can., 133(2): 70-82 .

[Abstract only available in French]
Des relevés effectués au moyen de chaluts benthiques entre 2004 et 2008 dans le bas Saguenay, l'estuaire maritime et le nord du golfe du Saint-Laurent ont permis d'identifier à l'espèce plus d'un million de poissons. Les captures ont été largement dominées par quatre espèces de prédateurs d'intérêt commercial: le flétan du Groenland, deux espèces de sébaste et la morue franche, mais on a dénombré plus d'une centaine d'espèces dont la moitié peuvent être considérées rares sur les fonds chalutés. Les espèces les plus abondantes dans les captures étaient également celles qui furent répertoriées dans une plus forte proportion des stations échantillonnées. Les espèces inusitées possèdent une distribution soit boréale, soit méridionale, et fréquentent généralement le plateau continental ou même le talus continental au-dessus de la plaine abyssale dans l'Atlantique. Les données issues de ces relevés ne fournissent qu'une vision partielle des communautés de poissons dans le Saint-Laurent: les poissons pélagiques et estuariens étaient mal représentés dans nos échantillons, les fonds rocheux ou escarpés n'étant généralement pas chalutables. Ce vaste territoire d'environ I5O 000 km2 est peuplé d'une faune variée.©2009 La Société Provancher d'histoire naturelle du Canada Certains poissons sont communs, d'autres représentent des visiteurs occasionnels en provenance des profondeurs de l'Atlantique, mais tous sont fascinants. Encore aujourd'hui, l'écologie d'un grand nombre de ces espèces reste mal connue.

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., L. MORISSETTE, M. CASTONGUAY, D.P. SWAIN, M.O. HAMMILL, D. CHABOT, J.M. HANSON, 2008. Interactions between marine mammals and fisheries: implications for cod recovery FOR COD RECOVERY. Pages 107-151 in J. Chen & C. Guo (ed.). Ecosystem Ecology Research Trends. Nova Science Publishers .

Abundance of many Atlantic cod (Gadus morhua) and groundfish stocks in the Northwest Atlantic declined to low levels in the early 1990s, resulting in cessation of directed fishing for these stocks, thus ending one of the largest and longest running commercial groundfish fisheries in the world. The stocks of the northern (nGSL) and southern Gulf of St. Lawrence (sGSL) were closed to directed cod fishing from 1994 to 1996 for the nGSL and from 1993 to 1997 for the sGSL, followed by the opening of a small directed fishery in the two systems. In the northern Gulf of St. Lawrence, the ecosystem biomass structure shifted dramatically from one dominated by demersal fish predators (Atlantic cod Gadus morhua, redfish Sebastes spp.) and small-bodied forage species (capelin Mallotus villosus, mackerel Scomber scombrus, herring Clupea harengus, northern shrimp Pandalus borealis) to one now dominated by only small-bodied forage species. The decline of large predatory fishes has left only marine mammals as top predators during the mid-1990s, and marine mammals and Greenland halibut Reinhardtius hippoglossoides during the early 2000s. Large changes also occurred in the biomass structure and ecosystem functioning of the adjacent southern Gulf of St Lawrence (sGSL) but they were not as dramatic. Although predatory fishes decreased between the mid-1980s and mid-1990s, and prey consumption by seal species increased considerably, large cod remained among the most important single predators on fish in the sGSL. The changes in top-predator abundance driven by human exploitation of selected species resulted in a major perturbation of the structure and functioning of both Gulf ecosystems and represent a case of fishery-induced regime shift. Overfishing influenced community biomass structure directly through preferential removal of larger-bodied fishes and indirectly through predation release. Species interactions are central to ecosystem considerations. In marine ecosystems, predation can be the major ecological process affecting fish populations and piscivory is often the largest source of fish removal, usually larger than fishing mortality. In both northern and southern Gulf ecosystems, predation mortality exceeded fishing mortality for most groups in recent years because fishing mortality was intentionally reduced by fisheries closures. Seals have benefited from reduced hunting (harvesting and culling/bounties) since the 1970s. Consumption of fish by marine mammals exceeded consumption by predatory fishes in the two ecosystems in the recent time periods. Since the collapse of groundfish stocks, commercial fisheries and seals have become important predators on predatory fishes-possibly slowing their recovery. In recent years, consumption by seals shifted towards species at lower trophic level (forage fishes and invertebrates), which were also the main target of fisheries. Thus, commercial fisheries and seals may have become important competitors of predatory fishes for the same resource.©2008 Nova Science Publishers, Inc.

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.

SAVENKOFF, C., M.-N. BOURASSA, D. BARIL, H.P. BENOÎT, 2007. Identification of ecologically and biologically significant areas for the Estuary and Gulf of St. Lawrence ; Identification des zones d'importance écologie et biologique pour l'estuaire et le golfe du Saint-Laurent. DFO, Canadian Science Advisory Secretariat, Research Document ; MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2007/015, 49 p .

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This report describes the analyses presented in a regional workshop held in Mont-Joli (Qc.) in order to synthesize the information across thematic layers based on physical, chemical, and biological data and identify the ecologically and biologically significant areas (EBSAs) for the Gulf of St. Lawrence Integrated Management (GOSLIM) initiative. Across all thematic layers, 96 important areas (IAs) have been identified based on the best scientific information available (geographically referenced data). These IAs are all characterized by specific scores for each of three main dimensions used to define EBSAs: uniqueness, aggregation, and fitness consequences. In synthesizing IAs across thematic layers, two general approaches were used based on: (1) each of the three main dimensions used separately and (2) the sum of their scores. The workshop concluded by identifying ten regions as EBSAs for the Estuary and the Gulf of St. Lawrence, covering 77,184 km2 (30&nsbp;% of the total area). All ten proposed EBSAs are related, at least in part, to IAs previously identified by a Delphic (expert opinion) approach. Potential sources of uncertainty and recommendations for the definition of EBSAs in other systems or in the present one in the future are discussed.

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.

MORISSETTE, L., M.O. HAMMILL, C. SAVENKOFF, 2006. The trophic role of marine mammals in the northern Gulf of St. Lawrence. Mar. Mamm. Sci., 22(1): 74-103 .

The trophic role of apex predators was evaluated in the northern Gulf of St. Lawrence ecosystem. An Ecopath model was developed for the period 1985-1987 prior to the collapse of commercially exploited demersal fish stocks in this area. Marine mammal trophic levels were estimated by the model at 4.1 for cetaceans, 4.4 for harp seals (Pagophilus groenlandicus), 4.7 for hooded seals (Cystophora cristata), 4.5 for gray seals (Halichoerus grypus), and 4.3 for harbor seals (Phoca vitulina). Harp seals were the third most important predator on vertebrate prey following large Atlantic cod (Gadus morhua) and redfish (Sebastes spp.). Different seal species preyed on different levels of the food chain. Harp seals preyed on most trophic groups, whereas larger seals, such as gray seals and hooded seals, mainly consumed higher trophic levels. The model suggested that apex predators had a negative effect on their dominant prey, the higher trophic level fish, but an indirect positive feedback on the prey of their preferred prey, mainly American plaice (Hippoglossoides platessoides), flounders, skates, and benthic invertebrates. Our results suggest that both marine mammals and fisheries had an impact on the trophic structure.7copy; 2006 Society for Marine Mammalogy.

SAVENKOFF, C., B. MORIN, D. CHABOT, M. CASTONGUAY, 2006. Main prey and predators of redfish (Sebastes spp.) in the northern Gulf of St. Lawrence during the mid-1980s,mid-1990s, and early 2000s. Can. Tech. Rep. Fish. Aquat. Sci., 2648, 23 p .

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We used results of mass-balance models to describe the changes in the structure and functioning of the northern Gulf of St. Lawrence ecosystem related to redfish (Sebastes spp.) for the mid-1980s, the mid-1990s, and the early 2000s. The net decrease in biomass of the demersal species in the early 1990s and the ensuing drop in predation led to an ecosystem structure dominated by small-bodied pelagic species and marine mammals. Redfish consumption largely decreased from the mid-1980s to the early 2000s. Large zooplankton, capelin (Mallotus villosus), and small zooplankton were the main prey consumed by redfish for each time period. There was a net decrease in total mortality and predation on redfish from the mid-1980s to early 2000s. Fishing mortality also decreased over the same time period as the redfish fishery in the Gulf has been under moratorium since 1995. Predation was the main cause of redfish mortality for each time period. The main predators of redfish were large cod (Gadus morhua) during the mid-1980s and harp seals (Pagophilus groenlandicus) and skates during the mid-1990s and early 2000s. Even though the proportion of redfish in the diet composition of each of these three predators was generally low, their predation could account for high percentages of total mortality on redfish. Cannibalism also appeared to be an important source of redfish mortality (between 10 and 15 % of total mortality)

SAVENKOFF, C., L. SAVARD, B. MORIN, D. CHABOT, 2006. Main prey and predators of northern shrimp (Pandalus borealis) in the northern Gulf of St. Lawrence during the mid-1980s, mid-1990s, and early 2000s. Can. Tech. Rep. Fish. Aquat. Sci., 2639, 28 p .

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We used results of mass-balance models to describe the changes in the structure and functioning of the northern Gulf of St. Lawrence ecosystem related to northern shrimp (Pandalus borealis) for the mid-1980s, the mid-1990s, and the early 2000s. The net decrease in biomass of the large-bodied demersal species and the ensuing drop in predation in the mid-1990s may explain the increase in abundance of the northern shrimp at the end of the 1990s. Shrimp was among the main prey species, and predation was the main cause of shrimp mortality for all time periods. Greenland halibut (Reinhardtius hippoglossoides) progressively replaced cod (Gadus morhua) and redfish (Sebastes spp.) as the main shrimp predators. Since the biomass of Greenland halibut sharply increased since 1995, its effect via predation as well as fishing pressure should be considered in the elaboration of management strategies for shrimp in the northern Gulf of St. Lawrence.

FRÉCHET, A., C. SAVENKOFF, J. GAUTHIER, 2006. Mise à jour concernant les mortalités par pêche non comptabilisées ; Updates concerning unaccounted fishing mortalities. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2006/086, 17 p .

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This paper covers a number of items related to unaccounted fishing mortalities: 1. Definition of the various categories of unaccounted fishing mortalities 2. A simulation of potential negative impacts of a change in mesh size 3. Three ghost fishing gear recovery programs in the Gulf of St. Lawrence 4. Fish survival experiments by gear type 5. By-catch in the shrimp fishery 6. Indirect evidence of unaccounted fishing mortality in ecosystem modelling These issues are raised in order to increase the awareness to the existence, monitoring, and research on unaccounted fishing mortalities in the Quebec region. Of relevance to the impact of the use of mobile bottom fishing gear is the issue of post-selection (or escape) mortality. Recent research in this field showed that such mortalities can be significant for some groundfish species. A better understanding of post selection mortality could allow assessing the mortality on targeted and non targeted species for the various fishing gears used. Also, such knowledge may improve the accuracy of stock assessments. No field research on this topic is currently being undertaken.

SAVENKOFF, C., M. CASTONGUAY, D. CHABOT, A. FRÉCHET, M.O. HAMMILL, L. MORISSETTE, 2006. Main prey and predators and estimates of mortality of Atlantic cod (Gadus morhua) in the northern Gulf of St. Lawrence during the mid-1980s, mid-1990s, and early 2000s. Can. Tech. Rep. Fish. Aquat. Sci., 2666, 32 p .

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We used results of mass-balance models to describe the changes in the structure and functioning of the northern Gulf of St. Lawrence ecosystem related to Atlantic cod (Gadus morhua) for the mid-1980s, the mid-1990s, and the early 2000s. The net decrease in biomass of the demersal species in the early 1990s and the ensuing drop in predation led to an ecosystem structure dominated by small-bodied pelagic species and marine mammals. Cod (both small and large) consumption largely decreased from the mid-1980s to the mid-1990s. Large zooplankton, shrimp (mainly Pandalus borealis), capelin (Mallotus villosus), and small planktivorous pelagics (mainly Atlantic herring Clupea harengus) were among the main prey consumed by small cod for each time period. The proportion of fish in the diet of large cod decreased from 77 % in the mid-1980s, when they mainly consumed capelin, to 49 % in the early 2000s. In the early 2000s, the main prey of large cod were large zooplankton and shrimp. There was a net decrease in total mortality and predation on small and large cod from the mid-1980s to the mid-1990s. Fishing mortality on large cod also decreased over the same time period (moratorium). From the mid- 1990s to the early 2000s, the biomass of both small and large cod doubled. Predation on small cod increased slightly over the same time period while predation on large cod was similar. However, the most noticeable increase in mortality on large cod from the mid-1990s to early 2000s came from fishing, which increased by a factor of 23. Cannibalism also appeared to be a non-negligible source of mortality on cod. A high proportion (between 30 and 40 %) of the total mortality of large cod could not be explained by either fishing or predation for each period (i.e., other mortality causes). This suggests that other processes in the ecosystem were not accounted for in the models

SAVENKOFF, C., F. GRÉGOIRE, M. CASTONGUAY, J.M. HANSON, D. CHABOT, D.P. SWAIN, 2006. Main prey and predators of Atlantic herring (Clupea harengus L.) in the Gulf of St. Lawrence during the mid-1980s, mid-1990s, and early 2000s. Can. Tech. Rep. Fish. Aquat. Sci., 2643, 28 p .

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We used results of mass-balance models to describe the changes in the structure and functioning of the northern and southern Gulf of St. Lawrence ecosystems related to the Atlantic herring populations (Clupea harengus L.) for the mid-1980s, the mid-1990s, and the early 2000s. Small and large zooplankton were the main prey of herring for each ecosystem and each time period. Herring was among the three main prey in both ecosystems for each time period. Predation was the main cause of herring mortality in the northern Gulf for all time periods and in the southern Gulf during the mid-1980s. Large cod (Gadus morhua) and redfish (Sebastes spp.) were progressively replaced by cetacea and seals as main herring predators from the mid-1980s to early 2000s in the northern Gulf. In the southern Gulf, large cod and harp seals were the main predators during the mid-1980s while predation and fishing mortality were of similar importance during the mid-1990s. Fishing was among the three main mortality causes in absolute terms in the northern and southern Gulf in each time period. Fishing effects on forage species since the early 1990s seem to counter the expected increases in biomass of these species following the net decrease in biomass of the demersal species and the ensuing drop in predation.

GRÉGOIRE, F., C. SAVENKOFF, D. CHABOT, 2006. Pêche, biologie, régime alimentaire et prédation du maquereau bleu (Scomber scombrus L.) dans les sous-régions 3 et 4 de l'OPANO en 2005 ; Atlantic mackerel (Scomber scombrus L.) fishery, biology, diet composition and predation in NAFO Subareas 3 and 4 in 2005. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2006/095, 84 p .

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In 2005, landings of Atlantic mackerel (Scomber scombrus L.) in the northwest Atlantic totalled 93,512 t, which represents a decrease of 14,020 t from 2004. In eastern Canada, 51,918 t were landed, including 40,724 t in Newfoundland only. Most of the landings of the west coast of Newfoundland were from unit areas 4Rb, 4Rc and 4Rd with 4,576 t, 1,334 t, and 7,614 t. On the east coast of Newfoundland, the most important landings were from unit areas 3Kd, 3Kh, 3Ki, 3Lb, and 3Lf with 8,570 t, 10,647 t, 3,380 t, 1,856 t, and 1,552 t, respectively. Mackerel catches of this importance are unusual for the east coast of Newfoundland. The other important unit areas were 4Tg and 4Tl in the southwestern Gulf of St. Lawrence with landings of 944 t and 625 t, respectively, and unit areas 4Xm and 4Xo, in Nova Scotia, with 3,513 t and 3 577 t. Since 2000, the most striking feature of the commercial mackerel fishery has been the presence of a high abundance and very large proportion of fish from the 1999 year-class. Over the past six years, this year-class has accounted for between 30% and 77% of the total number of fish caught, which hasn’t been seen since the late 1960s. In 2005, this year-class was dominant during the second and fourth quarter compared to the 2004 and 2003 year-classes for the third quarter. The analyses of the biological data indicate that the proportion of mature fish at age has decreased in recent years. The size at which 50% of the fish were mature, or L50, was 254.9 mm in 2005. Since 1999, the annual L50 values have been below or slightly above the minimum legal catch size of 250 mm. Data collected in the mid-1980s showed that mackerel in the Northern Gulf of St. Lawrence (Divisions 4RS) fed mainly on small (< 5 mm) and large (= 5 mm) zooplankton. During the mid-1990s and the beginning of the 2000s, the importance of the small and large zooplankton in the diet slightly decreased and was replaced by shrimp (Pandalus borealis) and capelin (Mallotus villosus). As shown by the results of different models of the Northern Gulf of St. Lawrence marine ecosystem, the main causes of mortality for mackerel in the mid-1980s were cetaceans, large cod (Gadus morhua), and large demersals. Cetaceans were still the main predators of mackerel in the mid-1990s and the beginning of 2000s. The same models showed that fishery related mortalities gradually increased from 2% in the mid-1980s to 15% in the mid-1990s, and finally to 30% of total mortality in the early 2000s. The main sources of uncertainty related to the present assessment are the unrecorded catches and the contribution of mackerel from Canadian waters in the American catches from the Gulf of Maine and Georges Bank areas. Because of this imprecision, of the recent increase of fishing effort and of the uncertainty regarding the results from the recent abundance surveys, the current TAC level of 75,000 t could be lowered over the next year

SAVENKOFF, C., M. CASTONGUAY, D. CHABOT, 2005. Effets de la pêche et la prédation sur l'écosystème du nord du golfe du Saint-Laurent: changements depuis le milieu des années 1980 jusqu'au milieu des années 1990. Naturaliste can., 129(1): 103-109 .

[Abstract only available in French]
En développant des modèles écosystémiques, le programme CDEENA qui vient de prendre fin, a cherché à expliquer les changements survenus dans le golfe depuis le milieu des années 1980 jusqu'au milieu des années 1990, et notamment leur impact sur la morue. Les résultats montrent notamment le rôle déterminant de la surpêche, l'importance de la prédation par les phoques mais aussi le changement des conditions environnementales.

SAVENKOFF, C., F. GREGOIRE, M. CASTONGUAY, D.P. SWAIN, D. CHABOT, J.M. HANSON, 2005. Main prey and predators of Atlantic mackerel (Scomber scombrus L.) in the northern and southern Gulf of St. Lawrence during the mid-1980s, mid-1990s, and early 2000s. Can. Tech. Rep. Fish. Aquat. Sci., 2619, 34 p .

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We used results of mass-balance models to describe the changes in the structure and functioning of the northern and southern Gulf of St. Lawrence ecosystems related to the Atlantic mackerel (Scomber scombrus L.) stock for the mid-1980s, the mid-1990s, and the early 2000s. The net decrease in biomass of demersal species and the ensuing drop in predation from the mid-1980s to the mid-1990s led to an ecosystem structure dominated by small-bodied pelagic species and marine mammals in the northern and southern Gulf. Predation was the main cause of mackerel mortality in each ecosystem for all time periods. However, demersal predators such as large cod and large demersals were progressively replaced by cetacea and seals as the main mackerel predators from the mid-1980s to mid-1990s (and early 2000s in the northern Gulf). Over the same time period, fishing mortality increased and became the second highest mortality cause in the northern Gulf for the early 2000s and the main mortality cause in the southern Gulf for the mid-1990s. Fishing mortality may have been underestimated due to non-negligible underreporting (discards at sea, recreational catches, and catches by bait fishermen)

SAVENKOFF, C., M. CASTONGUAY, R. METHOT, D. CHABOT, M.O. HAMMILL, 2005. Input data and parameter estimates for ecosystem models of the northern Gulf of St. Lawrence (2000-2002). Can. Tech. Rep. Fish. Aquat. Sci., 2588, 96 p .

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Mass-balance models were used to reconstruct trophic flows through the whole northern Gulf of St. Lawrence ecosystem (NAFO divisions 4Rs) for the 2000-2002 period. The whole-system model of the northern Gulf of St. Lawrence is divided into 31 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 parameter estimates from inverse modelling are also shown for comparisons. The successful development of ecosystem models will provide powerful new tools to evaluate the impact of human and environmental factors on marine ecosystems

FRÉCHET, A., J. GAUTHIER, P. SCHWAB, L. PAGEAU, C. SAVENKOFF, M. CASTONGUAY, D. CHABOT, C. TOURNOIS, J.-F. LUSSIER, J. SPINGLE, F. COLLIER, 2005. L’état du stock de morue du nord du golfe du Saint-Laurent (3Pn, 4RS) en 2004 ; The status of cod in the Northern Gulf of St. Lawrence (3Pn, 4RS) in 2004. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2005/060, 72 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 while the spawning biomass has reached a maximum of 378,000 tons in 1983. Afterwards, the stock was reduced to a minimum mature biomass of 9,000 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 remains low at 38,000 tons in 2005

GRÉGOIRE, F., C. SAVENKOFF, 2005. Pêche, biologie, régime alimentaire et prédation du maquereau bleu (Scomber scombrus L.) dans les sous-régions 3 et 4 de l’OPANO en 2004. MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2005/056, 63 p .

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In 2004, landings of Atlantic mackerel (Scomber scombrus L.) in the northwest Atlantic totalled 87,980 t, up to 8,489 t from 2003. In eastern Canada, 35,023 t were landed, including 32,966 t in Newfoundland only. The actual landings of 2004 should be higher since landings data from Prince Edward Island, New Brunswick, and Nova Scotia have not yet been accounted for. On the west coast of Newfoundland, the most important catches were realized in unit areas 4Rb (2,478 t), 4Rc (11,426 t), and 4Rd (7,492 t) in comparison with 3Kd (1,029 t) and 3Kh (10,123 t) for the east coast. Mackerel catches of this importance is unusual for the east coast of Newfoundland. The other important unit areas were 4Tf (966 t) and 4Xm (2,288 t) located respectively in the Magdalen Islands and close to Halifax, Nova Scotia. Since 2000, the most striking feature of commercial mackerel catches has been the presence of a high abundance and very large proportion of fish from the 1999 year-class. Over the past five years, this year-class has accounted for between 56 % and 77 % of the total number of fish caught, which hasn’t been seen since the late 1960s. In 2004, one- and two-year age groups were also predominant in fall catches made in the Southern Gulf of St. Lawrence (using lines) and on the East coast of Newfoundland (using purse seines). The presence of small mackerel in the latter area is unusual. Data collected in the mid-1980s showed that mackerel in the Northern Gulf of St. Lawrence fed mainly on small (< 5 mm) and large (= 5 mm) zooplankton. As shown by the results of a model of the Northern Gulf of St. Lawrence marine ecosystem, the main causes of mortality for mackerel in the mid-1980s were cetaceans, large cod (Gadus morhua), and large demersals. The proportion of mackerel making up the cetacean and large cod diets during this period was 18.7 % and 1.5 % respectively. The same model showed that fishery related mortalities gradually increased from 2 % in the early 1980s to 15 % in the mid-1990s, and finally to 27 % in the early 2000s.

GRÉGOIRE, F., C. SAVENKOFF, D. CHABOT, 2005. Capelan (Mallotus villosus) de l’estuaire et du golfe du Saint-Laurent (divisions 4RST de l’OPANO) en 2004. MPO, Secrétariat canadien de consultation scientifique, Document de recherche, 2005/058, 55 p .

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In 2004, capelin landings fished in the Estuary and the Gulf of St. Lawrence added up to 6,089 t. These landings represent a rise of 1,057 t compared with the 2003 level. With this increase, the 2004 landings are now just over the annual average landings of 5,487 t calculated for the 1990-2003 period. Purse seiners operating on the west coast of Newfoundland, and in unit area 4Rc in particular made for 76 % of landings realized in 2004. Between the end of the 1980s and the beginning of the 1990s, fishing seasons in this area were generally characterized by late fishery opening dates (and spawning activities). However, a relative stability in fishing dates has been observed since 2001. The average length of capelin caught in Division 4R showed a downward trend between 1986 and 1999, but a rise occurred thereafter. Nevertheless, the lengths measured in 2004 remain lower to those recorded in the 1980s. The dispersion index of capelin in the Estuary and Gulf of St. Lawrence has been characterized by rises in its long-term tendencies between 1990 and 2004. However, in 2004, a reduction of the index was measured for the West coast of Newfoundland and the southern Gulf. Small and large zooplanktons remain capelin’s main food source. In the mid-1980s, the main causes of capelin mortality stem from predation of large cod (Gadus morhua) and redfish (Sebastes spp.). Cetaceans, harp seals (Phoca groenlandica) and Greenland halibut (Reinhardtius hippoglossoides) replaced these two species during the 1990s and 2000s. In the mid-1980s, annual capelin consumption by its main predators totalled approximately one million tonnes. In the early 2000s, despite the strong decrease in abundance of its predators (cod and redfish), nearly 400,000 t of capelin per year was still being consumed, making this species the most important prey in the northern Gulf of St. Lawrence ecosystem.

GRÉGOIRE, F., C. SAVENKOFF, D. CHABOT, 2005. Capelin (Mallotus villosus) of the Estuary and Gulf of St. Lawrence (NAFO Divisions 4RST) in 2004. DFO, Canadian Science Advisory Secretariat, Research Document, 2005/058, 55 p .

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In 2004, capelin landings fished in the Estuary and the Gulf of St. Lawrence added up to 6,089 t. These landings represent a rise of 1,057 t compared with the 2003 level. With this increase, the 2004 landings are now just over the annual average landings of 5,487 t calculated for the 1990-2003 period. Purse seiners operating on the west coast of Newfoundland, and in unit area 4Rc in particular made for 76 % of landings realized in 2004. Between the end of the 1980s and the beginning of the 1990s, fishing seasons in this area were generally characterized by late fishery opening dates (and spawning activities). However, a relative stability in fishing dates has been observed since 2001. The average length of capelin caught in Division 4R showed a downward trend between 1986 and 1999, but a rise occurred thereafter. Nevertheless, the lengths measured in 2004 remain lower to those recorded in the 1980s. The dispersion index of capelin in the Estuary and Gulf of St. Lawrence has been characterized by rises in its long-term tendencies between 1990 and 2004. However, in 2004, a reduction of the index was measured for the West coast of Newfoundland and the southern Gulf. Small and large zooplanktons remain capelin’s main food source. In the mid-1980s, the main causes of capelin mortality stem from predation of large cod (Gadus morhua) and redfish (Sebastes spp.). Cetaceans, harp seals (Phoca groenlandica) and Greenland halibut (Reinhardtius hippoglossoides) replaced these two species during the 1990s and 2000s. In the mid-1980s, annual capelin consumption by its main predators totalled approximately one million tonnes. In the early 2000s, despite the strong decrease in abundance of its predators (cod and redfish), nearly 400,000 t of capelin per year was still being consumed, making this species the most important prey in the northern Gulf of St. Lawrence ecosystem.

SAVENKOFF, C., F. GRÉGOIRE, D. CHABOT, 2004. Main prey and predators of capelin (Mallotus villosus) in the northern and southern Gulf of St. Lawrence during the mid-1980s and mid-1990s. Can. Tech. Rep. Fish. Aquat. Sci., 2551, 30 p .

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Based on the results of mass-balance models, we present here the changes in the structure and functioning of the northern and southern Gulf of St. Lawrence ecosystems related to the capelin stock (Mallotus villosus) from the pre- to post-collapse period of the groundfish stocks, which were the main predators of capelin. The net decrease in biomass of these demersal species and the ensuing drop in predation from the mid-1980s to the mid-1990s led to an ecosystem structure dominated by small-bodied pelagic species and marine mammals in the northern and southern Gulf. Capelin is an important prey for many fish species (cod [Gadus morhua] and redfish [Sebastes spp.] in the northern Gulf; cod and mackerel [Scomber scombrus] in the southern Gulf) and for marine mammals (cetacea and seals). Capelin plays a key role in the food web by transferring energy from primary and secondary producers (on which it feeds) to higher trophic levels of the demersal and pelagic domains of the Gulf of St. Lawrence. Capelin was the main fish predator of small and large zooplankton in the northern Gulf for each time period and was also the main prey consumed by fish and marine mammals.

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.

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.

GRÉGOIRE, F., C. SAVENKOFF, H. BENOÎT, D. CHABOT, C. LÉVESQUE, J. HUDON, J. LAVERS, 2004. Pêche, biologie et distribution du capelan (Mallotus villosus) dans les divisions 4RST de l'OPANO en 2003 ; Capelin (Mallotus villosus) fishery, biology and distribution in NAFO Divisions 4RST in 2003. MPO, Secrétariat canadien de consultation scientifique, Document de recherche ; DFO, Canadian Science Advisory Secretariat, Research Document, 2004/136, 79 p .

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In 2003, capelin landings fished in the Estuary and the Gulf of St. Lawrence added up to 4,640 t. These landings represent a rise of 1,248 t compared with the 2002 level. However, despite this increase, the 2003 landings are still lower than the annual average landings of 5,522 t calculated for the 1990-2002 period. According to the industry, the recent drop in capelin landings would be caused by the loss of some significant markets and not a decrease in the abundance. The majority of landings realized in 2003 were made by purse seiners operating on the west coast of Newfoundland, and in unit area 4Rc in particular. Between the end of the 1980s and the beginning of the 1990s, fishing seasons in this area were generally characterized by late fishery opening dates (and spawning activities). The average length of capelin caught in Division 4R showed a downward trend between 1986 and 1999, but a rise occurred thereafter. Nevertheless, the lengths measured in 2003 still remain lower to those recorded in the 1980s. Indices measuring the dispersion and probabilities of finding capelin are now calculated from the groundfish and shrimp (Pandalus borealis) abundance research surveys. Between 1990 and 2003, these indices have been characterized by rises in their long-term tendencies. From 1997 to 2002, areas with high probabilities to find capelin in the northern Gulf of St. Lawrence expanded gradually towards the east. However in 2003, the west coast of Newfoundland was rather characterized by a reduction of such areas. For the southern Gulf, a very significant expansion of the species distribution characterized this area since the middle of the 1990s. This expansion seems to be linked with a reduction of the Magdalen Shallows surface area covered by water colder than 1 °C. Stomach contents sampled in the Gulf of St. Lawrence (Divisions 4R and 4S) since 1993 revealed that the capelin is a significant food resource for cod (Gadus morhua). A strong link would exist between the length of cod and the importance of capelin in its diet. Indeed, cods from 20 to 70 cm would be the most important predator for capelin.

SAVENKOFF, C., M. CASTONGUAY, A.F. VÉZINA, S.-P. DESPATIE, D. CHABOT, L. MORISSETTE, M.O. HAMMILL, 2004. Inverse modelling of trophic flows through an entire ecosystem: the northern Gulf of St. Lawrence in the mid-1980s. Can. J. Fish. Aquat. Sci., 61: 2194-2214 .

Mass-balance models using inverse methodology have been constructed for the northern Gulf of St. Lawrence ecosystem in the mid-1980s, before the groundfish collapse. The results highlight the effects of the major mortality sources (fishing, predation, and other sources of mortality) on the fish and invertebrate communities. Main predators of fish were large cod (Gadus morhua followed by redfish (Sebastesspp.), capelin (Mallotus villosus), and fisheries. Large cod were the most important predator of small cod, with cannibalism accounting for at least 44 % of the mortality of small cod. The main predators of large cod were harp (Phoca groenlandica) and grey (Halichoerus grypus) seals. However, predation represented only 2 % of total mortality on large cod. Mortality other than predation dominated the mortality processes at 52 % of the total, while the fishery represented 46 %. Tests were performed to identify possible sources of this unexplained mortality. The only way to significantly reduce unexplained mortality on large cod in the model was to increase landings of large cod above those reported. This suggests that fishing mortality was substantially underestimated in the mid-1980s, just before the demise of a cod stock that historically was the second largest in the northwest Atlantic.©2004 NRC Canada

SAVENKOFF, C., M. CASTONGUAY, 2003. L'écosystème du nord du Golfe du Saint-Laurent (milieu des années 1980). Naturaliste can., 127(1): 84-88 .

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.

SAVENKOFF, C., A.F. VÉZINA, P.C. SMITH, G. HAN, 2001. Summer transports of nutrients in the Gulf of St. Lawrence estimated by inverse modelling. Estuar. Coast. Shelf Sci., 52: 565-587 .

SAVENKOFF, C., A.F. VÉZINA, A. BUNDY, 2001. Inverse analysis of the structure and dynamics of the whole Newfoundland-Labrador shelf ecosystem. Can. Tech. Rep. Fish. Aquat. Sci., 2354, 56 p .

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In the present study, we use inverse methods to reconstruct trophic flows through the whole Newfoundland-Labrador Shelf ecosystem (NAFO 2J3KLNO) for the 1985-1987 period. This was a period of relatively constant biomass for the major species prior to the groundfish stock collapses. The whole-system model of the Newfoundland-Labrador Shelf is divided into 31 functional groups or compartments from phytoplankton and detritus to marine mammals and seabirds, including harvested species of pelagic, demersal, and benthic domains. The results are compared with a mass balance model using the Ecopath approach with the same data set. Successful development of the suite of ecosystem models proposed for 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 in a variety of Atlantic shelf ecosystems.

PACKARD, T., W. CHEN, D. BLASCO, C. SAVENKOFF, A.F. VEZINA, R. TIAN, L. ST-AMAND, S.O. ROY, C. LOVEJOY, B. KLEIN, J.-C. THERRIAULT, L. LEGENDRE, R.G. INGRAM, 2000. Dissolved organic carbon in the Gulf of St. Lawrence. Deep-Sea Res., Part II , Top. Stud. Oceanogr., 47(3-4): 435-459 .

VÉZINA, A.F., C. SAVENKOFF, S. ROY, B. KLEIN, R. RIVKIN, J.-C. THERRIAULT, L. LEGENDRE, 2000. Export of biogenic carbon and structure and dynamics of the pelagic food web in the Gulf of St. Lawrence Part 2. Inverse analysis. Deep-Sea Res., Part II , Top. Stud. Oceanogr., 47(3-4): 609-635 .

SAVENKOFF, C., A.F. VEZINA, S. ROY, B. KLEIN, C. LOVEJOY, J.-C. THERRIAULT, L. LEGENDRE, R. RIVKIN, C. BÉRUBÉ, J.-E. TREMBLAY, N. SILVERBERG, 2000. Export of biogenic carbon and structure and dynamics of the pelagic food web in the Gulf of St. Lawrence : Part 1. Seasonal variations. Deep-Sea Res., Part II, Top. Stud. Oceanogr. 47(3-4): 585-607 .

TIAN, R.C., A.F. VÉZINA, L. LEGENDRE, R.G. INGRAM, B. KLEIN, T. PACKARD, S. ROY, C. SAVENKOFF, N. SILVERBERG, J.-C. THERRIAULT, J.É. TREMBLAY, 2000. Effects of pelagic food-web interactions and nutrient remineralization on the biogeochemical cycling of carbon : a modeling approach. Deep-Sea Res., Part II, Top. Stud. Oceanogr. 47(3-4): 637-662 .

ROY, S., N. SILVERBERG, N. ROMERO, D. DEIBEL, B. KLEIN, C. SAVENKOFF, A.F. VÉZINA, J.-É. TREMBLAY, L. LEGENDRE, R.B. RIVKIN, 2000. Importance of mesozooplankton feeding for the downward flux of biogenic carbon in the Gulf of St. Lawrence (Canada). Deep-Sea Res., Part II, Top. Stud. Oceanogr., 47(3-4): 519-544 .

DESROSIERS, G., C. SAVENKOFF, M. OLIVIER, G. STORA, K. JUNIPER, A. CARON, J.-P. GAGNÉ, L. LEGENDRE, S. MULSOW, J. Grant, S. Roy, A. GREHAN, P. SCAPS, N. SILVERBERG, B. KLEIN, J.-É. TREMBLAY, J.-C. THERRIAULT, 2000. Trophic structure of macrobenthos in the Gulf of St. Lawrence and on the Scotian Shelf. Deep-Sea Res., Part II, Top. Stud. Oceanogr., 47(3-4): 663-697 .

VEZINA, A.F., C. SAVENKOFF, 1999. Inverse modeling of carbon and nitrogen flows in the pelagic food web of the northeast subarctic Pacific. Deep-Sea Res., Part II, 46: 2909-2939 .

ST-AMAND, L., R. GAGNON, T.T. PACKARD, C. SAVENKOFF, 1999. Effects of inorganic mercury on the respiration and the swimming activity of shrimp larvae, Pandalus borealis. Comp. Biochem. Physiol., C: Pharmacol. Toxicol. Endocrinol., 122(1): 33-43 .

SAVENKOFF, C., A.F. VÉZINA, Y. GRATTON, D. BLASCO, J.-P. CHANUT, 1998. Distribution of microplankton assemblages in relation to mesoscale variations in the lower St. Lawrence Estuary (June-July 1990). Can. Tech. Rep. Hydrogr. Ocean Sci., 197, 26 p .

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As part of a multidisciplinary program to study the physical and biological interactions regulating carbon flows in the lower St. Lawrence Estuary (LSLE), three cruises were conducted in June-July 1990 during a neap-spring tidal cycle when biological production was expected to be maximal. This study presents the first analyses of phytoplankton biomass, primary production, and respiratory ETS activity along with the identification and size structure of the autotrophic and heterotrophic planktonic communities throughout the bloom period in the LSLE. Two areas of accumulation of phytoplankton cells and biomass with different hydrologic and biological characteristics were observed during the study. The factors that triggered these phytoplankton blooms are analyzed.

SAVENKOFF, C., A.F. VÉZINA, Y. GRATTON, 1997. Effect of a freshwater pulse on mesoscale circulation and phytoplankton distribution in the lower St. Lawrence Estuary. J. Mar. Res., 5: 353-381 .

DEVINE, L., C. SAVENKOFF, A.F. VÉZINA, J.-P. CHANUT, S. ROY, L. COMEAU, V. DUBÉ, D. BLASCO, Y. GRATTON, 1997. Compilation des données biologiques et chimiques dans l'estuaire maritime du Saint-Laurent : programme COUPPB 1989, 1990 et 1991. Rapp. stat. can. hydrogr. sci. océan., 150, 103 p .

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To better understand the physical-biological interactions regulating carbon flows in the Lower St. Lawrence Estuary (LSLE), a multidisciplinary program known as COUPPB (COUplage des Processus Physiques et Biogéochimiques; Mesoscale Physical-Biogeochemical Coupling) was carried out in the LSLE from June 1989 to July 1991. This report presents the stations sampled and the variables measured during the five missions. The objective of the first two missions (COUPPB89 : June-July 1989; COUPPB90-1 : June-July 1990) was to extensively sample the area to resolve the mesoscale variations (10-20 km, 5-10 days). The subsequent missions were planned, based on the data from these first missions, to examine the relationships between the different physical, chemical, and biological variables at stations characterized by strongly contrasting hydrodynamic conditions (COUPPB90-2 : September 1990; COUPPB91-1 : May 1991 : COUPPB91-2 : July 1991).

RIVKIN, R.B., L. LEGENDRE, D. DEIBEL, J.-E. TREMBLAY, B. KLEIN, K. CROCKER, S. ROY, N. SILVERBERG, C. LOVEJOY, F. MESPLÉ, N. ROMERO, M.R. ANDERSON, P. MATTHEWS, C. SAVENKOFF, A. VÉZINA, J.-C. THERRIAULT, J. WESSON, C. BÉRUBÉ, R.G. INGRAM, 1997. Measuring biogenic carbon flux in the ocean : response. Science (Wash.), 275: 554-555 .

SAVENKOFF, C., A. VÉZINA, J.-C. THERRIAULT, 1997. Le cycle du carbone dans le golfe du Saint-Laurent. Nouv. Sci., 8(7): 4-6 .

LAFLEUR, C., Y. GRATTON, J.-P. CHANUT, C. SAVENKOFF, A.F. VÉZINA, P. VINET, 1996. Distribution des paramètres océanographiques des eaux de l'estuaire du Saint-Laurent au large de Rimouski (juin-juillet 1990). Rapp. stat. can. sci. halieut. aquat., 981, 130 p .

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This report presents distributions of temperature, salinity, baroclinic currents, suspended particulate material, and dissolved oxygen concentrations obtained during the repeated sampling of closely spaced stations in the lower St. Lawrence Estuary between June 30 and July 9, 1990. The data are presented as a set of cross-estuary vertical sections. Horizontal sections of temperature, salinity, and baroclinic currents at 15 and 40 m depth are also presented. This representation shows the presence of an anticyclonic eddy associated with the passage of a warmer and fresher water mass through the study region. (DBO).

RIVKIN, R.B., L. LEGENDRE, D. DEIBEL, J.-É. TREMBLAY, B. KLEIN, K. CROCKER, S. ROY, N. SILVERBERG, C. LOVEJOY, F. MESPLÉ, N. ROMERO, M.R. ANDERSON, P. MATTHEWS, C. SAVENKOFF, A. VÉZINA, J.-C. THERRIAULT, J. WESSON, C. BÉRUBÉ, R.G. INGRAM, 1996. Vertical flux of biogenic carbon in the ocean : is there food web control?. Science (Wash.), 272: 1163-1166 .

SAVENKOFF, C., A.F. VÉZINA, T.T. PACKARD, N. SILVERBERG, J.-C. THERRIAULT, W. CHEN, C. BÉRUBÉ, A. MUCCI, B. KLEIN, F. MESPLÉ, J.-E. TREMBLAY, L. LEGENDRE, J. WESSON, R.G. INGRAM, 1996. Distributions of oxygen, carbon, and respiratory activity in the deep layer of the Gulf of St. Lawrence and their implications for the carbon cycle. Can. J. Fish. Aquat. Sci., 53: 2451-2465 .

The Gulf of St. Lawrence (GSL) is a semi-enclosed sea with an estuarine circulation forced by runoff from the St. Lawrence and Great Lakes drainage systems and balanced by a deep inflow of oceanic waters through the Laurentian Channel. Based on samples collected between July 1992 and June 1994 during Phase 1 of the CJGOFS program conducted in the Gulf of St. Lawrence, new data are presented on the carbon and nutrient chemistry as well as respiratory activity in the deep waters. Organic carbon fluxes estimated from sediment trap data, deepwater respiratory activity, and benthic respiration measurements are consistent with those obtained from the changes in the dissolved oxygen concentration of the deep waters along the Laurentian Channel. These flux estimates suggest that approximately 10 % of the local primary production reaches the deep layer (> 200 m) and the sediments in the GSL. The vertical carbon budget is almost balanced in the eastern part of the gulf, but approximately half of the carbon produced in the surface layer of the northwestern gulf cannot be accounted for. The difference in hydrodynamic and biological conditions prevailing in both areas may explain the observations.

SAVENKOFF, C., T.T. PACKARD, M. RODIER, M. GÉRINO, D. LEVÈVRE, M. DENIS, 1995. Relative contribution of dehydrogenases to overall respiratory ETS activity in some marine organisms. J. Plankton Res., 17:1593-1604 .

SAVENKOFF, C., J.-P. CHANUT, A.F. VÉZINA, Y. GRATTON, 1995. Distribution of biological activity in the lower St. Lawrence Estuary as determined by multivariate analysis. Estuar. Coast. Shelf Sci., 40: 647-664 .

SAVENKOFF, C., A.F. VÉZINA, J.-P. CHANUT, Y. GRATTON, 1995. Respiratory activity and CO 2 production rates of microorganisms in the Lower St. Lawrence Estuary. Cont. Shelf Res., 15: 613-631 .

SAVENKOFF, C., L. ST-AMAND, P. OUELLET, T.T. PACKARD, 1995. An index of respiratory efficiency in the shrimp Pandalus borealis (Kroeyer) larvae. Can. Tech. Rep. Fish. Aquat. Sci., 2072, 26 p .

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Respiration (physiological and enzymatic potential), growth (dry-weight [DW], body and carapace lengths), and protein content were measured on the larval stages of the northern shrimp Pandalus borealis. The relationship between oxygen consumption and growth through the larval development was examined under controlled laboratory conditions of temperature and food mixture. Body and carapace lengths, as well as respiration (R) increased as a linear function of time (days) during larval development, whereas biomass, measured as dry-weight and protein content, and enzymatic potential respiration (ETSA) are best described as exponential functions of time during the experiment. There was a decreasing trend in the weight-specific respiration rate (dry-weight-based, QO2) during development from hatching to the last larval instar. We estimate that the zoeae of P. borealis require a minimum of 2.95 to 0.44 J mg DW-1 d-1 from the zoeae I stage to the megalopa stage. We propose that the R/ETSA ratio could be used as a quantitative index of the sensitivity of shrimp larvae to environmental stress. The first larval instar would be the most vulnerable, since respiration is close to the respiratory capacity. With growth, and the decrease of the R/ETSA ratio, the later larval instars had a higher potential to generate energy and to respond to environmental stress.

SAVENKOFF, C., L. COMEAU, A.F. VÉZINA, Y. GRATTON, 1994. Seasonal variation of the biological activity in lower St. Lawrence Estuary. Can. Tech. Rep. Fish. Aquat. Sci., 2006, 22 p .

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Three to four stations located in the Laurentian Trough were investigated six times during four missions. Three missions were conducted during periods of expected maximal biological production according to the seasonal variation in the lower St. Lawrence Estuary. Two missions took place during the principal summer bloom, and one was conducted during a secondary bloom in the fall. The fourth mission occurred during a period of low surface production, following the melting of the ice cover. The physico-chemical and biological characteristics present during all missions distinguished the upwelling region (stations 67 and 26) from the plume region (stations 23 and 95). We generally measured the highest salinities and lowest temperatures in the upwelling region whereas the lowest salinities and the highest temperatures were observed in the plume region. The significant relationships between phytoplankton biomass, surface production, and surface and deep respiration indicated that there was a coupling between the surface biological activity and the aphotic metabolism over a seasonal scale. Different explanations are presented to qualitatively and quantitatively describe the respiration/production budgets during these missions.