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P.-M. CHOUINARD, J.-D. DUTIL, 2011. The structure of demersal fish assemblages in a cold, highly stratified environment. ICES J. Mar. Sci., 68(9): 1896-1908 .
Fish are a major component of marine ecosystems, with many species co-occuring in the same habitats. Potential interactions among species and with the environment can be studied through the identification of species assemblages. Data from bottom trawl surveys (2004–2008) conducted in the estuary and northern Gulf of St Lawrence were analysed using multivariate methods (cluster, multidimensional scaling, and detrended canonical correspondence analysis) to describe the structure and composition of demersal fish assemblages, including rare and smaller non-commercial species. The spatial variability in environmental conditions that characterizes the study area has a significant impact on the composition of fish assemblages in the region. In all, 35 taxa were classified as key, and 6 main fish assemblages were described, based on catch in numbers. These assemblages had a coherent spatial distribution in the study area, associated with either depth, salinity and temperature, or dissolved oxygen. The analyses showed overall strong correlations between species abundance and prevalent environmental conditions and explained 18.4 % of the variance in species abundance data and 79.2 % of the variance in the speciesenvironment relationship.©2011 Oxford
DUTIL, J.-D., S. PROULX, P.-M. CHOUINARD, D. BORCARD, 2011. A hierarchical classification of the seabed based on physiographic and oceanographic features in the St. Lawrence. Can. Tech. Rep. Fish. Aquat. Sci., 2916, 79 p .
A hierarchical framework has been proposed to classify marine waters surrounding North America into 24 different marine ecoregions based on large-scale oceanographic features. One of those ecoregions (Acadian-Atlantic) includes shelf waters from the Strait of Belle Isle (Canada) down to Cape Cod (U.S.A.) and encompasses the St. Lawrence estuary and Gulf. The present report aims at proposing a hierarchical classification of the seafloor at the scale of the megahabitat for the St. Lawrence estuary and Gulf as a basis for mapping and describing marine habitats for conservation and integrated management purposes. Information on salinity, temperature, dissolved oxygen, depth, slope, and variability in landscape and sediments were aggregated using a grid made up of 100 km2 cells. Based on that information, cluster analyses were conducted grouping cells into 13 different megahabitats. Four megahabitats described the deep waters, and areas outside channels formed 9 megahabitats: four in the southern Gulf and five in the northern Gulf. These groups of cells were spatially coherent. The tool proposes a novel way of making validated and integrated data available to end users. Potential applications include the screening of areas considered for inclusion in a network of protected areas and a quantitative assessment of surface areas for each class of habitat. the method can also be applied to describe the habitats of species at risk.
LAROCQUE, R., J-D. DUTIL, S. PROULX, M. THORNE, P.-M. SCALLON-CHOUINARD, M.-H. GENDRON, J. PLOURDE, T. SCHMITT, 2010. Contribution à la description de l'habitat des loups de mer (Anarhichas spp.) près de la péninsule gaspésienne par vidéo remorquée et relevés acoustiques multifaisceaux. Rapp. tech. can. sci. halieut. aquat., 2902, 51 p .
This report presents the results of several initiatives that examine the potential habitat of wolffish (Anarhichas spp.) in the Gulf of St. Lawrence and in particular near the Gaspé peninsula. The habitat features were examined at different spatial scales: by towed video, multibeam acoustic surveys and an examination of historical catch data. High-resolution bathymetry and backscatter coupled with information extracted from video allowed for a detailed description of environments known to be used by wolfish. Features believed to be favourable to wolfish were identified on both survey sites, including shelters and glacial scours. The resulting information is presented within the attached multimedia DVD-ROM. The complimentary nature of these methods and the management implications for a species at risk are discussed.
NOZERES, C., D. ARCHAMBAULT, P.-M. CHOUINARD, J. GAUTHIER, R. MILLER, E. PARENT, P. SCHWAB, L. SAVARD, J.-D. DUTIL, 2010. Guide d'identification des poissons marins de l'estuaire et du nord du golfe du Saint-Laurent et protocoles suivis pour leur échantillonnage lors des releves par chalut entre 2004 et 2008 ; Identification guide for marine fishes of the estuary and northern Gulf of St. Lawrence and sampling protocols used during trawl surveys between 2004 and 2008. Can. Tech. Rep. Fish. Aquat. Sci., 2866, 168 p .
The annual survey that scientists conduct on large research trawlers is an important source of information on the status of marine resources harvested in the estuary and northern Gulf of St. Lawrence. The main objective of the survey is to estimate the abundance and biomass of five commercially important species, i.e., Atlantic cod (Gadus morhua), Greenland halibut (Reinhardtius hippoglossoides), Acadian (Sebastes fasciatus) and deepwater (Sebastes mentella) redfish, and northern shrimp (Pandalus borealis). For several years, biologists have sought to improve the integration of stock status and ecosystem information, which has required a greater effort to better describe catches of other species of fish and invertebrates. The long-used sampling and observation protocol has evolved into a much more complex, detailed model. However, in implementing this protocol, difficulties have been encountered in accurately identifying ten or so species caught at each trawling station. This report provides a guide to the identification of fish species likely to be caught in surveys in the estuary and northern Gulf of St. Lawrence. This visual guide is designed as a practical tool for training staff and ensuring the quality of data collected. This report also describes the sampling and examination protocol for fish catches used for surveys conducted aboard the CGSS Teleost between 2004 and 2008 and presents a brief descriptive analysis of fish catches during this period.
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.
SCALLON-CHOUINARD, P.-M., J.-D. DUTIL, S. HURTUBISE, 2007. Liste des espèces de poissons inventoriés dans lestuaire maritime du Saint-Laurent entre 1930 et 2005. Rapp. tech. can. sci. halieut. aquat., 2719, 64 p .
Data concerning species of fish that inhabit the lower St. Lawrence Estuary, i.e., the section between Ile Rouge and Pointe des Monts, are fragmentary particularly for those species not harvested commercially. There is no account of each species distribution in the area, not to mention their life history. The present report provides an exhaustive list of fish species reported in the lower St. Lawrence Estuary. Three sources of information were examined, primary publications and reports, and two data bases, DFOs At-Sea Observer Program data base (landings, 1991-2005) and DFOs annual groundfish and northern shrimp abundance survey for the estuary and northern Gulf of St. Lawrence area (1978 - 2003). The lower St. Lawrence Estuary has a diversified fish fauna: reliable or multiple data sources have recorded and confirmed 99 species. These species belong to 80 different genus and 41 different families. Many of those species may reside in the study area whereas others are rare or occasional visitors or transit through the area en route to freshwater or the Gulf of St. Lawrence. Only 25 of those species were reported for the Manicouagan marine protected area during the same period
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