Pubblicazione scientifica

Factors affecting energy expenditure in a declining fur seal population

FILONE TECNOLOGICO	TEMA
economia circolare e sostenibilità

RIASSUNTO

Abstract

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.

DATA

Data di pubblicazione: 26/12/2019

AUTORI

MCHURON ELIZABETH A
STERLING JEREMY T
COSTA DANIEL P
GOEBEL MICHAEL E

ENTE DI AFFERENZA

JOINT INST ATMOSPHERE & OCEAN UNIV WASHINGTON
MARINE MAMMAL LABORATORY ALASKA FISHERIES SCIENCE CENTER NATIONAL MARINE FISHERIES SERVICE – NOAA 7600 SAND POINT WAY NE SEATTLE WA 98115 USA
DEPT ECOLOGY & EVOLUTION UNIV CALIFORNIA SANTA CRUZ

RIVISTA

Conservation Physiology, 7(1), coz103

IMPACT FACTOR

3,150

indietro