Seasonal ocean temperature and the survival of first-year little penguins Eudyptula minor in south-eastern Australia

Ocean temperature has been shown to be related to various demographic parameters in several seabird species, but ultimately its influence on breeding success and survival are paramount. The timing and success of breeding of little penguins Eudyptula minor in south-eastern Australia have been shown t...

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Bibliographic Details
Published in:Marine ecology. Progress series (Halstenbek) 2012-05, Vol.454, p.263-272
Main Authors: Sidhu, LA, Dann, P, Chambers, L, Catchpole, EA
Format: Article
Language:English
Subjects:
Eudyptula minor
Marine
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Summary:Ocean temperature has been shown to be related to various demographic parameters in several seabird species, but ultimately its influence on breeding success and survival are paramount. The timing and success of breeding of little penguins Eudyptula minor in south-eastern Australia have been shown to correlate with local sea-surface temperatures (SST) and the east-west sea-temperature gradient across Bass Strait several months earlier. However, the causal links between ocean temperature and these demographic variables are not readily apparent due to their lagged nature. Using 41 yr of data on little penguins in south-eastern Australia, we carried out a mark-recapture analysis to examine if the changing SST and sea-temperature gradient (east-west difference between 2 locations in Bass Strait) are associated with survival probability in the first year of life. First-year survival is correlated with (1) an east-west sea-temperature gradient in Bass Strait in the winter after fledging, with an increased temperature gradient associated with decreased survival and (2) the mean SST in the autumn after fledging, with warmer seas associated with increased survival. SST alone does not provide the best model for explaining first-year survival. Projections suggest that SST in south-eastern Australia and sea-temperature gradient in Bass Strait will both increase due to global warming. The net effect of an increased sea-temperature gradient in winter (which has a negative influence) and increased SST in autumn (which has a positive influence) on first-year survival is uncertain, given the current lack of knowledge concerning the relationship between the sea-temperature gradient and SST in Bass Strait.
ISSN:0171-8630
1616-1599
DOI:10.3354/meps09709