[MARMAM] New publication linking sea ice to body condition of humpback whales using historic whaling records

Janelle Braithwaite janelle.braithwaite at gmail.com
Tue Apr 7 20:54:31 PDT 2015

My co-authors and I would like to share with you our recent publication in
Polar Biology (abstract below) - please email me if you would like a pdf

Janelle Braithwaite
janelle.braithwaite at gmail.com


*From sea ice to blubber: linking whale condition to krill abundance using
historical whaling records*
Janelle E. Braithwaite, Jessica J. Meeuwig, Tom B. Letessier, K. Curt S.
Jenner, Andrew S. Brierley

Krill (*Euphausia superba*) are fundamentally important in the Southern
Ocean ecosystem, forming a critical food web link between primary producers
and top predators. Krill abundance fluctuates with oceanographic
conditions, most notably variation in winter sea ice, and is susceptible to
environmental change. Although links between local krill availability and
performance of land breeding, central place foragers are recognised, the
effects of krill variability on baleen whales remain largely unclear
because concurrent long-term data on whale condition and krill abundance do
not exist. Here, we quantify links between whale body condition and krill
abundance using a simple model that links krill abundance to sea ice
extent. Body condition of humpback whales (Megaptera novaeangliae) caught
in west Australian waters between 1947 and 1963 was estimated from oil
yields in whaling records. Annual estimates of krill abundance in the
Southern Ocean where those whales foraged (70°–130°E) were correlated
significantly with contemporary annual winter sea ice extent. We hindcast
sea ice extent for the whaling period from reconstructed temperature data
and found that whale body condition was significantly correlated with
hindcasted winter sea ice extent, supporting the hypothesis that variations
in body condition were likely mediated by associated krill fluctuations. As
humpback whales migrate and breed on finite energy stores accrued during
summer foraging in the Antarctic, changes in sea ice and concomitant
changes in krill abundance have long-term implications for their condition
and reproductive success.
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