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Historical changes in mean trophic level of southern Australian fisheries


Alleway, HK and Connell, SD and Ward, TM and Gillanders, BM, Historical changes in mean trophic level of southern Australian fisheries, Marine and Freshwater Research, 65, (10) pp. 884-893. ISSN 1323-1650 (2014) [Refereed Article]

Copyright Statement

Journal compilation copyright CSIRO 2014

DOI: doi:10.1071/MF13246


Decreases in the mean trophic level (MTL) of fishery catches have been used to infer reductions in the abundance of high trophic level species caused by fishing pressure. Previous assessments of southern Australian fisheries have been inconclusive. The objectives of the present study were to provide more accurate estimates of MTL using disaggregated taxonomic and spatial data. We applied the model of MTL to fisheries catch statistics for the state of South Australia from 1951 to 2010 and a novel set of historical market data from 1936 to 1946. Results show that from 1951 to 2010, MTL declined by 0.16 of a trophic level per decade; a rate greater than the global average of 0.10 but equivalent to similar regional investigations in other areas. This change is mainly attributable to large increases in catches of sardine, rather than reductions in the catches of high trophic level species. The pattern is maintained when the historical data is included, providing a time line from 1936 to 2010. Our results show a broadening of the catch of lower trophic levels and suggest care in interpretation of MTL of catches because reductions do not necessarily reflect change in high trophic level species by fishing pressure.

Item Details

Item Type:Refereed Article
Keywords:fishing down the food web, mean trophic level, South Australia
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Fisheries sciences
Research Field:Fisheries management
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Marine biodiversity
UTAS Author:Ward, TM (Associate Professor Timothy Ward)
ID Code:147598
Year Published:2014
Web of Science® Times Cited:9
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2021-11-09
Last Modified:2021-12-01

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