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No evidence for a decline in the density of Antarctic krill Euphausia superba Dana, 1850, in the Southwest Atlantic sector between 1976 and 2016


Cox, MJ and Candy, S and de la Mare, WK and Nicol, S and Kawaguchi, S and Gales, N, No evidence for a decline in the density of Antarctic krill Euphausia superba Dana, 1850, in the Southwest Atlantic sector between 1976 and 2016, Journal of Crustacean Biology, 38, (6) pp. 656-661. ISSN 0278-0372 (2018) [Refereed Article]


Copyright Statement

Copyright The Authors(s) 2018. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)

DOI: doi:10.1093/jcbiol/ruy072


The Antarctic marine environment is changing, and changes in the Southwest Atlantic sector have included decreases in sea ice and increases in water temperature. Associated with these changes is a reported 38% and 81% per decade decline in the numerical density (hereafter density) of Antarctic krill Euphausia superbaDana, 1850, between 1976 and 2003. Few changes in other components of the ecosystem that could be attributed to such a change, such as a mass decline in krill-dependent predators, have been detected. In an ecosystem so dependent on this keystone species, a massive population decline in krill ought to have had an obvious effect. In the absence of such an effect, it is timely to revisit the issue of the purported decline in krill density. The original analysis that indicated a decline in krill density was based on the 2004 version of KRILLBASE, a database of net samples. We analysed the publicly available and updated version (version 1, accessed 30 November 2017) and our analyses did not suggest a significant decline in krill density. Rather, after accounting for sampling heterogeneity and habitat variables, average krill density appears to have been stable but with considerable inter-annual variability. Since our results were unable to find any evidence for a decline in krill density we recommend a re-appraisal of many of the paradigms that underlie much of the recent thinking about ecosystem change Antarctic waters. Such a revision is necessary to provide a firmer foundation for predictions of the effects of climate change and resource extraction on the Southern Ocean ecosystem.

Item Details

Item Type:Refereed Article
Keywords:krill, population trends, net samples, use of models, populations, Southern Ocean ecosystem
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Animal Production and Animal Primary Products
Objective Group:Fisheries - wild caught
Objective Field:Wild caught crustaceans (excl. rock lobster and prawns)
UTAS Author:Nicol, S (Dr Stephen Nicol)
ID Code:137282
Year Published:2018
Web of Science® Times Cited:36
Deposited By:Ecology and Biodiversity
Deposited On:2020-02-07
Last Modified:2020-03-30
Downloads:15 View Download Statistics

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