Dear friends and colleagues,
My co-authors and I are happy to share a link (
https://rdcu.be/ca4mm)
to our Open Access paper in Scientific Reports on the fine-scale
feeding behaviour and diet of bowhead whales in the Eastern Canadian
Arctic.
Bowhead whales use two foraging strategies in response to fine-scale differences in zooplankton vertical distribution
Sarah M. E. Fortune1,2,3*, Steven H. Ferguson2, Andrew W. Trites1, Justine M. Hudson2 & Mark F. Baumgartner3
As zooplanktivorous predators, bowhead whales (Balaena
mysticetus) must routinely locate patches of prey that are energy‑rich
enough to meet their metabolic needs. However, little is known about how
the quality and quantity of prey might influence
their feeding behaviours. We addressed this question using a new
approach that included: (1) multi‑scale biologging and unmanned aerial
system observations of bowhead whales in Cumberland Sound, Nunavut
(Canada), and (2) an optical plankton counter (OPC) and
net collections to identify and enumerate copepod prey species through
the water column. The OPC data revealed two prey layers comprised almost
exclusively of lipid‑rich calanoid copepods. The deep layer contained
fewer, but larger, particles (10% greater
overall biomass) than the shallow prey layer. Dive data indicated that
the whales conducted long deep Square‑shaped dives (80% of dives;
averaging depth of 260.4 m) and short shallow Square‑shaped dives (16%;
averaging depth of 22.5 m) to feed. The whales
tended to dive proportionally more to the greater biomass of
zooplankton that occurred at depth. Combining behavioural recordings
with prey sampling showed a more complex feeding ecology than previously
understood, and provides a means to evaluate the energetic
balance of individuals under current environmental conditions.
Wishing you all the best,
Sarah Fortune