Please use this identifier to cite or link to this item:
|Scopus||Web of Science®||Altmetric|
|Title:||Historical changes in mean trophic level of southern Australian fisheries|
|Citation:||Marine and Freshwater Research, 2014; 65(10):884-893|
|Heidi K. Alleway, Sean D. Connell, Tim M. Ward and Bronwyn M. Gillanders|
|Abstract:||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.|
|Keywords:||Fisheries; fisheries catch; ‘fishing down’; marine food webs; South Australia|
|Rights:||Journal compilation © CSIRO 2014|
|Appears in Collections:||Earth and Environmental Sciences publications|
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.