Shift in benthic assemblages and organisms’ diet at salmon farms: community structure and stable isotope analyses

Marine Ecology Progress Series

Tasman P. Crowe¹  Mary K. Dunagan¹  Myriam D. Callier¹  Marie-Paule Bataille¹  Jennifer Coughlan¹  S#xe9bastien Lefebvre¹ 

关键词: Aquaculture;    Organic matter;    Stable isotope;    Community structure;    Diet shift;    Trophic structure;   

DOI  :  10.3354/meps10251

学科分类：海洋学与技术

来源: Inter-Research

【 摘 要 】

ABSTRACT: The extent of the influence of salmon farming on the environment and on the uptake of particulate and dissolved effluents by benthic organisms was assessed using community structure and stable isotope analyses. Sediment cores were collected in 2 directions: perpendicular and parallel to the main residual current, 0, 25 and 200 m from 2 salmon farms (Millstone and Cranford) located in Mulroy Bay, Ireland. In addition, artificial substrates were placed for 2 mo at 1 m depth 0, 25 and 200 m from one farm to trace the uptake of farm-related nutrients by fouling organisms. The extent of measurable change in benthic communities (abundance, diversity, structure, trophic composition) depended on residual current direction. Intraspecific variation in isotopic values in benthic invertebrates was mostly explained by distance from cages. Organisms collected at impacted sites exhibited a shift in isotopic composition towards that of farm wastes. A shift in δ¹³C was observed in several invertebrates, including the polychaetes Malacoceros fuliginosus and Nephtys hombergii, Nematoda and the anemone Anthopleura balii. Fouling communities collected on artificial structures, mainly composed of the tunicate Ascidiella aspersa, showed higher δ¹⁵N values at fish cage sites compared to sites 200 m away. The study demonstrated that fish effluents were assimilated and became food sources for several organisms.

【 授权许可】

Unknown