Sea surface temperature predicts the movements of an Arctic cetacean: the bowhead whale

Philippine Chambault,Kristin L Laidre,Toby A Patterson,Outi Tervo,Rikke G Hansen,Mads Peter Heide-Jørgensen,Christoffer Moesgaard Albertsen

doi:10.1038/s41598-018-27966-1

Abstract

The effects of climate change constitute a major concern in Arctic waters due to the rapid decline of sea ice, which may strongly alter the movements and habitat availability of Arctic marine mammals. We tracked 98 bowhead whales by satellite over an 11-year period (2001–2011) in Baffin Bay - West Greenland to investigate the environmental drivers (specifically sea surface temperature and sea ice) involved in bowhead whale’s movements. Movement patterns differed according to season, with aggregations of whales found at higher latitudes during spring and summer likely in response to sea-ice retreat and increasing sea temperature (SST) facilitated by the warm West Greenland Current. In contrast, the whales moved further south in response to sea temperature decrease during autumn and winter. Statistical models indicated that the whales targeted a narrow range of SSTs from −0.5 to 2 °C. Sea surface temperatures are predicted to undergo a marked increase in the Arctic, which could expose bowhead whales to both thermal stress and altered stratification and vertical transport of water masses. With such profound changes, bowhead whales may face extensive habitat loss. Our results highlight the need for closer investigation and monitoring in order to predict the extent of future distribution changes.

Highlights

In response to climate change, modifications of the environmental conditions encountered by marine species might strongly alter their movements and their habitat[1,2,3]
The estimated length of the whales differed significantly according to the tagging location, being longer for those tagged in Disko Bay, than those tagged in Foxe Basin, or in Cumberland Sound
The use of a large tracking dataset (n = 98) together with environmental covariates provided novel information on the crucial role played by the seaice retreat and increasing sea temperature (SST) in driving the movements of a cetacean that resides year-round in Arctic waters

Summary

Introduction

In response to climate change, modifications of the environmental conditions encountered by marine species might strongly alter their movements and their habitat[1,2,3]. Several studies involving satellite tracking of individuals from this population have shown migratory patterns for this species, and noted that an aggregation occurs in Disko Bay, West Greenland, from February to June[15,29,32] In this area, the strong inter-annual site fidelity of bowhead whales can be partly explained by high concentrations of copepods, making this site an important foraging ground[33,34,35]. Track lines or dive data from some of the whales have been presented in previous publications (see Supplementary Material Table S1), but this is the first analysis of the habitat use based on the complete set of tracking data by combining the three tagging locations for this population This large sample size and long time series will provide a reliable picture of the environmental variables involved in the habitat selection of this Arctic marine cetacean

Methods

Results

Conclusion