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Please use this identifier to cite or link to this item: http://www.lsln.net.au/jspui/handle/1/13806
Type: journalArticle
Title: The trophic role of marine mammals in the northern Gulf of St. Lawrence
Authors: Morissette, L.
Hammill, M.O.
Savenkoff, C.
Keywords: Cystophora cristata;Gulf of St. Lawrence;Halichoerus grypus;Pagophilus groenlandicus;Phoca vitulina;Predation;cetaceans;ecosystem model;food web;gray seal;harbor seal;harp seal;hooded seal
Year: 2006
Citation: Volume: 22
Issue: 1
Abstract: 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.
Zotero ID: RJ7MWM7E
URL: http://onlinelibrary.wiley.com/doi/10.1111/j.1748-7692.2006.00007.x/abstract
URL: http://www.lsln.net.au/jspui/handle/1/13806
ISSN: 1748-7692
DOI: 10.1111/j.1748-7692.2006.00007.x
Journal Title: Marine Mammal Science
Geo Location: none
Appears in Collections:North Coast Local Land Services

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