Seasonal growth and mortality of Euphausia superba in Admiralty Bay, South Shetland Islands, Antarctica

The mean size of adult and juvenile Euphausia superba in populations sampled during 1979–1986 in Admiralty Bay, South Shetland Islands, Antarctica shows a sinusoidal seasonal oscillation: mean krill size is reduced in winter. This has previously been interpreted as evidence of negative growth. Month...

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Bibliographic Details
Published in:ICES Journal of Marine Science
Main Authors: McClatchie, Sam, Rakusa-Suszczewski, Stanislaw, Filcek, Krzysztof
Format: Text
Language:English
Published: Oxford University Press 1991
Subjects:
Articles
South Shetland Islands
Admiralty Bay
Antarc*
Antarctica
Euphausia superba
Online Access:http://icesjms.oxfordjournals.org/cgi/content/short/48/3/335
https://doi.org/10.1093/icesjms/48.3.335
Description
Summary:The mean size of adult and juvenile Euphausia superba in populations sampled during 1979–1986 in Admiralty Bay, South Shetland Islands, Antarctica shows a sinusoidal seasonal oscillation: mean krill size is reduced in winter. This has previously been interpreted as evidence of negative growth. Monthly total mortality was highest over winter, between July and October: there was notable interannual variability. We suggest that the winter-time decrease in mean krill size in Admiralty Bay results from predation reducing the numbers of larger, but less abundant krill, at a time when juvenile krill spawned the previous summer are recruiting to the population. This mechanism can explain the seasonal oscillation of mean krill size, without invoking negative growth.

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