[MARMAM] New publication: Field metabolic rates in a declining fur seal population

Elizabeth McHuron emchuron at ucsc.edu
Wed Jan 8 08:38:32 PST 2020

Dear colleagues,

My co-authors and I are pleased to announce our new publication "Factors
affecting energy expenditure in a declining fur seal population" in
Conservation Physiology. The article is open access

Quantifying metabolic rates and the factors that influence them is key to
wildlife conservation efforts because anthropogenic activities and habitat
alteration can disrupt energy balance, which is critical for reproduction
and survival. We investigated the effect of diving behaviour, diet and
season on field metabolic rates (FMR) and foraging success of lactating
northern fur seals (Callorhinus ursinus) from the Pribilof Islands during a
period of population decline. Variation in at-sea FMR was in part explained
by season and trip duration, with values that ranged from 5.18 to 9.68 W kg
−1 (n = 48). Fur seals experienced a 7.2% increase in at-sea FMR from
summer to fall and a 1.9% decrease in at-sea FMR for each additional day
spent at sea. There was no effect of foraging effort, dive depth or diet on
at-sea FMR. Mass gains increased with trip duration and were greater in the
fall compared with summer, but were unrelated to at-sea FMR, diving
behaviour and diet. Seasonal increases in at-sea FMR may have been due to
costs associated with the annual molt but did not appear to adversely
impact the ability of females to gain mass on foraging trips. The overall
high metabolic rates in conjunction with the lack of any diet-related
effects on at-sea FMR suggests that northern fur seals may have reached a
metabolic ceiling early in the population decline. This provides indirect
evidence that food limitation may be contributing to the low pup growth
rates observed in the Pribilof Islands, as a high metabolic overhead likely
results in less available energy for lactation. The limited ability of
female fur seals to cope with changes in prey availability through
physiological mechanisms is particularly concerning given the recent and
unprecedented environmental changes in the Bering Sea that are predicted to
have ecosystem-level impacts.

Happy New Year and please don't hesitate to contact me with any questions (
emchuron at ucsc.edu or emchuron at uw.edu).

Kind regards,


Elizabeth McHuron, Ph.D.
Research Scientist
University of Washington JISAO
115 McAllister Way
Santa Cruz, CA 95060
emchuron at uw.edu <emchuron at ucsc.edu>
emchuron at ucsc.edu
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