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Consumption of aquaculture waste affects the fatty acid metabolism of a benthic invertebrate

Citation

White, CA and Bannister, RJ and Dworjanyn, SA and Husa, V and Nichols, PD and Kutti, T and Dempster, T, Consumption of aquaculture waste affects the fatty acid metabolism of a benthic invertebrate, Science of The Total Environment, 586 pp. 1170-1181. ISSN 0048-9697 (2017) [Refereed Article]

Copyright Statement

Copyright 2017 Elsevier B.V.

DOI: doi:10.1016/j.scitotenv.2017.02.109

Abstract

Trophic subsidies can drive widespread ecological change, thus knowledge of how keystone species respond to subsidies is important. Aquaculture of large carnivorous fish generates substantial waste as faeces and lost feed, providing a food source to mobile benthic invertebrates. We used a controlled feeding study combined with a field survey to better understand the interaction between salmon aquaculture and the sea urchin, Echinus acutus, a dominant mobile invertebrate in Norwegian fjords. We tested if diets affected urchin fatty acid composition by feeding them one of three diet treatments ("aquafeed", "composite" and "natural") for 10 weeks. To test if proximity to fish farms altered E. acutus fatty acid composition, populations were sampled at 10 locations in Hardangerfjord and Masfjord (Western Norway) from directly adjacent and up to 12 km from farms. Fatty acids were measured in gonads and eggs in the diet experiment and in gonads and gut contents from wild animals. Urchins directly assimilated aquaculture waste at farm sites, as evidenced by elevated linoleic acid (LA), oleic acid (OA) and ∑ LA, OA in their tissues. The diet experiment highlighted the biosynthetic and selective dietary sparing capacity of E. acutus in both gonads and eggs, with evidence for the elongation and desaturation of eicosapentaenoic acid (EPA) and arachidonic acid (ARA) from C18 fatty acid precursors. Elevated biosynthesis of non-methylene interrupted (NMI) fatty acids, in particular 20:3Δ7,11,14 and 20:2 Δ5,11, were also linked to a high C18 fatty acid, low ≥ C20 long-chain polyunsaturated fatty acid (LC-PUFA) diet. Fatty acid composition of gonads of wild urchins indicated a highly variable diet. The study indicates that the generalist feeding ecology of E. acutus, coupled with extensive biosynthetic capacity, enables it to exploit aquaculture waste as an energy-rich trophic subsidy.

Item Details

Item Type:Refereed Article
Keywords:trophic subsidy, fatty acid, dietary tracer, aquaculture waste, Echinus acutus, linoleic acid
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and Estuarine Ecology (incl. Marine Ichthyology)
Objective Division:Environment
Objective Group:Ecosystem Assessment and Management
Objective Field:Ecosystem Assessment and Management of Marine Environments
Author:White, CA (Ms Camille White)
ID Code:115389
Year Published:2017
Web of Science® Times Cited:1
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2017-03-21
Last Modified:2017-05-02
Downloads:0

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