Lipid and mercury profiles of 61 mid‐trophic species collected off south‐eastern Australia
H. Pethybridge A B D , R. Daley A , P. Virtue B , E. C. V. Butler A , D. Cossa C and P. D. Nichols AA CSIRO Wealth from Oceans National Research Flagship and CSIRO Marine and Atmospheric Research, GPO Box 1538, Hobart, Tas. 7001, Australia.
B IMAS, University of Tasmania, Private Bag 129, Hobart, Tas. 7001, Australia.
C IFREMER, Centre de Méditerranée, BP 330, F.83507 La Seyne sur mer, France.
D Corresponding author. Email: heidi.pethybridge@csiro.au
Marine and Freshwater Research 61(10) 1092-1108 https://doi.org/10.1071/MF09237
Submitted: 22 September 2009 Accepted: 14 April 2010 Published: 14 October 2010
Abstract
Total mercury (Hg) concentrations and lipid composition data, including fatty acid profiles, for 61 mid‐trophic species (fish, cephalopods, crustaceans) collected from continental slope waters off south‐east Australia were examined. Overall, Hg concentrations were greatest in fish (0.01–0.30 μg g–1 ww) (with highest content found in barracouta (Thyrsites atun) and whiptails (Coelorinchus fasciatus)), compared with cephalopods (0.01 and 0.17 μg g–1 ww) and crustaceans (<0.04 μg g–1 ww). Lipid composition varied between species and within habitat (mesopelagic, bathypelagic and benthic). Mean total lipid content ranged from 0.5 to 13.2% ww, and in most species was dominated by triacylglycerols and phospholipids. In fish and squid, fatty acids were generally dominated by monounsaturated fatty acids, whereas crustaceans were higher in polyunsaturated fatty acids. Multidimensional scaling analyses separated species into groupings according to their fatty acid composition that could be interpreted with taxonomic, trophic and habitat information. Discriminant function analyses indicated the most influential (predictor) fatty acids for each group. Biochemical profile classifications can be used in wider trophodynamic studies to understand contaminant transfer, trophic relationships and community dynamics in marine environments.
Additional keywords: deep‐sea, ecosystem dynamics, fatty acids, lipids, mercury, mid‐trophic prey, mid‐water.
Acknowledgements
We thank the captain and crew of the ‘Adriatic Pearl’ for sample collection. We are grateful to Mark Lewis, Alastair Graham and Peter Last for taxonomically identifying prey species. We thank Bernard Averty and Stephan Guedron for their assistance with mercury analyses. Dianna Furlani supplied details of the MIDOC sampling method. Daniel Holdsworth maintained the GC‐MS. We thank Cathy Bulman, Beth Fulton and two anonymous referees for helpful comments on the manuscript. This project was partly funded by the Goddard Sapin‐Jaloustre Trust Fund in association with IFREMER Centre de Nantes, France.
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