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Influence of climatic changes on the parasites of Atlantic cod Gadus morhua off coastal Labrador, Canada

Published online by Cambridge University Press:  12 April 2024

R.A. Khan  and
C.V. Chandra
R.A. Khan*
Affiliation:
Department of Biology and Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Newfoundland, Canada, A1B 3X9
C.V. Chandra
Affiliation:
Department of Biology and Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Newfoundland, Canada, A1B 3X9
*
*Fax: 709 737 3220 E-mail:[email protected]
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Abstract

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A study was conducted in 2000 and 2003, following the collapse of the commercial fishery in 1990, to compare metazoan parasites of Atlantic cod Gadus morhua, captured off coastal Labrador, with samples taken in 1980 and 1986. Fish were captured by otter trawl offshore in the North Atlantic Fish Organisation subarea 2J. Parasites were removed from the digestive tract, stained, identified and compared between the different groups. Both the prevalence and mean abundance of trematodes, larval nematodes and E. gadi were significantly lower in fish taken in 2000 and 2003 than in 1980. While mean values of trematodes and nematodes declined in 1986, those of Echinorhynchus gadi remained unchanged in 1986 and 1990. Four-year-old cod sampled in 1990 harboured significantly fewer E. gadi than older age groups. The most commonly occurring trematodes included Podocotyle reflexa, Lepidapedon elongatum, Derogenes varicus and Hemiurus levinseni while the larval nematode, Anisakis sp. was predominant. Comparison of offshore samples taken in 2000 and 2003 with others taken in previous years suggests an overall decline of parasites coincident with a change in climatic conditions, the absence of a major food source, namely capelin Mallotus villosus, of cod and ultimately the decline of the Labrador population.

Type
Research Article
Information
Journal of Helminthology , Volume 80 , Issue 2 , June 2006 , pp. 193 - 197
Copyright
Copyright © Cambridge University Press 2006

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