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Bibliographie de l'Institut Maurice-Lamontagne

Mammifères marins - Baleines / Megaptera novaeangliae / Rorqual à bosse, Baleine à bosse

ANDERWALD, P., A.K. DANIELSDOTTIR, T. HAUG, F. LARSEN, V. LESAGE, R.J. REID, G.A. VIKINGSSON, A.R. HOELZEL, 2011. Possible cryptic stock structure for minke whales in the North Atlantic : implications for conservation and management. Biol. Conser., 44: 2479-2489.

[Résumé disponible seulement en anglais]
The minke whale is the last of the great whale species to be hunted in significant numbers. Effective management must include an understanding of how genetic diversity is divided and distributed among putative local populations, and as for many migratory species, this is complicated for the minke whale by large-scale seasonal movement among geographic regions. The problem is that the geographic identity of breeding populations is not known, and instead these whales are predictably found and hunted where different breeding stocks may mix on seasonal feeding grounds. Here we use microsatellite DNA and mtDNA markers to investigate minke whale population structure across the species’ range in the North Atlantic. We found no evidence of geographic structure comparing putative populations in recognized management areas, though some limited structure had been indicated in earlier studies. However, using individual genotypes and likelihood assignment methods, we identified two putative cryptic stocks distributed across the North Atlantic in similar proportions in different regions. Some differences in the proportional representation of these populations may explain some of the apparent differentiation between regions detected previously. The implication would be that minke whales range extensively across the North Atlantic seasonally, but segregate to some extent on at least two breeding grounds. This means that established stock boundaries in the North Atlantic, currently used for management, should be re-considered to ensure the effective conservation of genetic diversity.©2011 Elsevier Ltd.

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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La Station de Recherche des Îles Mingan (ou MICS) effectue le monitorage des rorquals bleus fréquentant le golfe du Saint-Laurent (GSL) depuis 1979. Jusqu’à présent, plus de 400 individus ont pu être photo-identifiés dans diverses régions du Golfe. Ce rapport vise à décrire qualitativement la distribution, l’abondance et le comportement des rorquals bleus à une échelle tant spatiale que temporelle. Les informations collectées sur les rorquals à bosse sont également décrites. Les résultats obtenus confirment le caractère généralement nomade du rorqual bleu et laissent présager que le GSL ne constitue qu’un fragment de l’aire d’alimentation estival de l’espèce. Les résultats révèlent également l’existence de divers comportements individuels par rapport à la fidélité au site : visiteurs occasionnels vs. réguliers et individus cosmopolites vs. exclusifs. Aussi, nous avons été capables d’effectuer une distinction entre les diverses zones de concentration des observations en se basant sur les tendances temporelles dans la fréquentation des sites. Alors que l’estuaire maritime semble être la région où les rorquals bleus sont le plus souvent observés, le nombre d’individus fréquentant la Minganie a décliné au cours du temps, au point où les observations sont maintenant un phénomène rare. Parallèlement, un nombre toujours croissant de rorquals à bosse a été observé chaque année dans cette même région. Comme plusieurs questions sur leur écologie générale restent sans réponse, le but de cette étude était d’augmenter l’état des connaissances sur le comportement et l’utilisation de l’habitat par ces rorquals. Les mammifères marins pourraient exercer le rôle de « sentinelle écosystémique ». Dans ce contexte, le monitorage à long terme permettrait de détecter toute tendance spatiale ou temporelle susceptible de refléter un changement dans l’environnement

DONIOL-VALCROZE, T., D. BERTEAUX, P. LAROUCHE, R. SEARS, 2008. Influence of thermal fronts on habitat selection by four rorqual whale species in the Gulf of St. Lawrence. Mar. Ecol. Prog. Ser., 335: 207-216.

[Résumé disponible seulement en anglais]
Understanding the factors influencing habitat selection is critical to improving management and conservation plans for large whales. Many studies have linked the distribution of cetaceans to basic environmental features such as underwater topography and sea surface temperature (SST), but the mechanisms underlying these relationships are poorly understood. Dynamic mesoscale processes like thermal fronts are prime candidates to link physiographic factors to whale distribution because they increase biological productivity and aggregate prey. However, previous studies of large whales have found little evidence of such associations, possibly because they were not at the appropriate spatio-temporal scales. We quantified the relationship between SST fronts and the distribution of blue Balaenoptera musculus, finback B. physalus, humpback Megaptera novaeangliae and minke B. acutorostrata whales in the northern Gulf of St. Lawrence. We compared the distribution of 1094 whale sightings collected from boat surveys conducted in 1996 to 2000 to the locations of frontal areas determined from 61 satellite maps. The distributions of whales and thermal fronts were highly correlated (random resampling and Mantel tests of matrix similarity). Spatial distributions differed among species, probably reflecting differences in feeding strategies. Identification of surface fronts from satellite imagery thus effectively complemented field observations of whales. These findings significantly increase our understanding of habitat quality in rorqual whales, and encourage a greater use of dynamic environmental variables in future studies of whale habitat use. ©2007 Inter-Research

DONIOL-VALCROZE, T., D. BERTEAUX, P. LAROUCHE, R. SEARS, 2007. Influence of thermal fronts on habitat selection by four rorqual whale species in the Gulf of St. Lawrence. Mar. Ecol. Prog. Ser., 335: 207-216 .

[Résumé disponible seulement en anglais]
Understanding the factors influencing habitat selection is critical to improving management and conservation plans for large whales. Many studies have linked the distribution of cetaceans to basic environmental features such as underwater topography and sea surface temperature (SST), but the mechanisms underlying these relationships are poorly understood. Dynamic mesoscale processes like thermal fronts are prime candidates to link physiographic factors to whale distribution because they increase biological productivity and aggregate prey. However, previous studies of large whales have found little evidence of such associations, possibly because they were not at the appropriate spatio-temporal scales. We quantified the relationship between SST fronts and the distribution of blue Balaenoptera musculus, finback B. physalus, humpback Megaptera novaeangliae and minke B. acutorostrata whales in the northern Gulf of St. Lawrence. We compared the distribution of 1094 whale sightings collected from boat surveys conducted in 1996 to 2000 to the locations of frontal areas determined from 61 satellite maps. The distributions of whales and thermal fronts were highly correlated (random resampling and Mantel tests of matrix similarity). Spatial distributions differed among species, probably reflecting differences in feeding strategies. Identification of surface fronts from satellite imagery thus effectively complemented field observations of whales. These findings significantly increase our understanding of habitat quality in rorqual whales, and encourage a greater use of dynamic environmental variables in future studies of whale habitat use. ©2007 Inter-Research