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Spatial overlap of shark nursery areas and the salmon farming industry influences the trophic ecology of Squalus acanthias on the southern coast of Chile

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Gaitan-Espitia, JD, Gomez, D, Hobday, AJ, Daley, R, Lamilla, J and Cardenas, L 2017 , 'Spatial overlap of shark nursery areas and the salmon farming industry influences the trophic ecology of Squalus acanthias on the southern coast of Chile' , Ecology and Evolution, vol. 7, no. 11 , pp. 3773-3783 , doi: 10.1002/ece3.2957.

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Abstract

Potential interactions between marine predators and humans arise in the southern coast of Chile where predator feeding and reproduction sites overlap with fisheries and aquaculture. Here, we assess the potential effects of intensive salmon aquaculture on food habits, growth, and reproduction of a common predator, the spiny dogfish—identified as Squalus acanthias via genetic barcoding. A total of 102 (89 females and 13 males) individuals were collected during winter and summer of 2013–2014 from the Chiloé Sea where salmon aquaculture activities are concentrated. The low frequency of males in our study suggests spatial segregation of sex, while immature and mature females spatially overlapped in both seasons. Female spiny dogfish showed a functional specialist behavior as indicated by the small number of prey items and the relative high importance of the austral hake and salmon pellets in the diet. Immature sharks fed more on pellets and anchovies than the larger hake-preferring mature females. Our results also indicate that spiny dogfish switch prey (anchovy to hake) to take advantage of seasonal changes in prey availability. Despite differences in the trophic patterns of S. acanthias due to the spatial association with intensive salmon farming, in this region, there appears to be no difference in fecundity or size at maturity compared to other populations. Although no demographic effects were detected, we suggest that a range of additional factors should be considered before concluding that intensive aquaculture does not have any impact on these marine predators.

Item Type: Article
Authors/Creators:Gaitan-Espitia, JD and Gomez, D and Hobday, AJ and Daley, R and Lamilla, J and Cardenas, L
Keywords: artisanal fishery, reproduction, salmon industry, sexual maturity, Squalus acanthias, trophic ecology
Journal or Publication Title: Ecology and Evolution
Publisher: John Wiley and Sons Ltd
ISSN: 2045-7758
DOI / ID Number: 10.1002/ece3.2957
Copyright Information:

Copyright 2017 the Authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/

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