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Trophic structure and biomagnification of mercury in an assemblage of deepwater chondrichthyans from southeastern Australia

Citation

Pethybridge, H and Butler, ECV and Cossa, D and Daley, R and Boudou, A, Trophic structure and biomagnification of mercury in an assemblage of deepwater chondrichthyans from southeastern Australia, Marine Ecology Progress Series, 451 pp. 163-174. ISSN 0171-8630 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 Inter-Research

DOI: doi:10.3354/meps09593

Abstract

Stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) were used to evaluate trophic structure and mercury biomagnification in an assemblage of 16 deepwater chondrichthyans (primarily, 2 squaliformes: Centroselachus crepidater and Etmopterus baxteri) collected from continental waters off southeastern Australia from 2004 to 2006. In all species, mean trophic position (TP; quantified by δ15N) ranged from 3.5 to 4.7 (indicative of tertiary consumers). Minor variation in δ13C enrichment was observed between species (−18.7 to −17.1‰) with the exception of Squalus acanthias (−19.3 ± 0.1‰). Total mercury (THg) levels ranged from 0.3 to 4.5 mg kg−1 (wet mass, wm) with the highest concentrations correlated with increasing individual size and TP. Using published (TP and THg) data on low-mid trophic prey groups collected from the study area, THg biomagnification factors between selected predator−prey associations and trophic magnification factors (TMF) within various assemblage and community groupings were calculated. As an assemblage, deepwater elasmobranchs demonstrated moderate rates of THg biomagnification, as indicated by the regression slope (0.69 TP giving a TMF of 4.8) while higher rates were reported in the extended continental shelf/slope community (1.13 TP giving a TMF of 13.4). Among-system differences in TMF were found between low-mid and mid-high order food chains as well as between shelf/upper-slope, mid-slope, and benthic food webs, signifying that bioaccumulation pathways are closely related to physical-chemical (bathome affinity) and community (presumably species composition and food chain length) structure.

Item Details

Item Type:Refereed Article
Keywords:Hg, biomagnification, trophic transfer, deep-sea, elasmobranchs, stable isotopes
Research Division:Agricultural and Veterinary Sciences
Research Group:Fisheries Sciences
Research Field:Fisheries Management
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Marine Flora, Fauna and Biodiversity
Author:Pethybridge, H (Ms Heidi Pethybridge)
Author:Daley, R (Mr Ross Daley)
ID Code:83702
Year Published:2012
Web of Science® Times Cited:17
Deposited By:IMAS Research and Education Centre
Deposited On:2013-03-21
Last Modified:2017-05-29
Downloads:0

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