Dear Marmamm Community,
We are pleased to announce our recent publication:
Beluga whale summer habitat associations in the Nelson River estuary, western
Hudson Bay, Canada
Abstract
To understand beluga whale (Delphinapterus leucas) estuarine use in the Nelson
River estuary, southwest Hudson Bay, we recorded and examined beluga movements
and habitat associations for the July through August period in 2002-2005. We
compared locations of belugas fitted with satellite transmitters ("tags")
(2002-2005) and aerial-surveyed (2003 and 2005) belugas for years of differing
freshwater flow from the Nelson River which is influenced by hydroelectric
activity. Using the beluga telemetry location data, we estimated an early
August behavioral shift in beluga distribution patterns from local estuarine
use to a progressively more migratory behavior away from the estuary. The
timing of this shift in behavior was also apparent in results of beluga aerial
surveys from the 1940s-1960s, despite environmental changes including later
freeze-up and warming ocean temperatures. Overall, during the higher than
average discharge ("wet") year of 2005, the three tagged belugas ranged farther
from the Nelson River but not farther from the nearest shore along southwestern
Hudson Bay, compared to the 10 tagged belugas tracked during the "dry" years of
2002-2004 with below average discharges. Aerial survey data for 2003 and 2005
display a similar dry vs. wet year shift in spatial patterns, with no
significant change in overall density of belugas within the study area. In the
Nelson estuary, proximity to the fresh-salt water mixing area may be more
important than the shallow waters of the upper estuary. Killer whales (Orcinus
orca) were observed in the Churchill area (200 km northwest) during each year
of study, 2002-05, and belugas may benefit from the proximity to shallow
estuary waters that provide protection from the larger-bodied predator. Study
results contribute to an understanding of the influence of environmental
variation on how and why belugas use estuaries although considerable
uncertainties exist and additional research is required.
An open access PDF may be obtained from:
PLOS ONE:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0181045
All the best,
Alex Smith
Senior Consultant Ecologist
Ramboll Environ
Tampa, Florida
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