Seasonal diving and foraging behaviour of Eastern Canada−West Greenland bowhead whales

Climate change may affect the foraging success of bowhead whales Balaena mysticetus by altering the diversity and abundance of zooplankton species available as food. However, assessing climate-induced impacts first requires documenting feeding conditions under current environmental conditions. We co...

Full description

Saved in:
Bibliographic Details
Published in:Marine ecology. Progress series (Halstenbek) 2020-06, Vol.643, p.197-217
Main Authors: Fortune, Sarah M. E., Ferguson, Steven H., Trites, Andrew W., LeBlanc, Bernard, LeMay, Valerie, Hudson, Justine M., Baumgartner, Mark F.
Format: Article
Language:English
Subjects:
Aquatic crustaceans
Aquatic mammals
Balaenidae
Cetacea
Climate change
Copepoda
Depth
Environmental assessment
Environmental conditions
Feeding
Food availability
Foraging
Foraging behavior
Foraging habitats
Marine mammals
Phytoplankton
Plankton
Polar environments
Prey
Seasonal variation
Seasonal variations
Species composition
Species diversity
State space models
Summer
Telemetry
Vertical distribution
Whales
Winter
Zooplankton
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Climate change may affect the foraging success of bowhead whales Balaena mysticetus by altering the diversity and abundance of zooplankton species available as food. However, assessing climate-induced impacts first requires documenting feeding conditions under current environmental conditions. We collected seasonal movement and dive-behaviour data from 25 Eastern Canada−West Greenland bowheads instrumented with time-depth telemetry tags and used state-space models to examine whale movements and dive behaviours. Zooplankton samples were also collected in Cumberland Sound (CS) to determine species composition and biomass. We found that CS was used seasonally by 14 of the 25 tagged whales. Area-restricted movement was the dominant behaviour in CS, suggesting that the tagged whales allocated considerable time to feeding. Prey sampling data suggested that bowheads were exploiting energy-rich Arctic copepods such as Calanus glacialis and C. hyperboreus during summer. Dive behaviour changed seasonally in CS. Most notably, probable feeding dives were substantially shallower during spring and summer compared to fall and winter. These seasonal changes in dive depths likely reflect changes in the vertical distribution of calanoid copepods, which are known to suspend development and overwinter at depth during fall and winter when availability of their phytoplankton prey is presumed to be lower. Overall, CS appears to be an important year-round foraging habitat for bowheads, but is particularly important during the late summer and fall. Whether CS will remain a reliable feeding area for bowhead whales under climate change is not yet known.
ISSN:0171-8630
1616-1599
DOI:10.3354/meps13356