[MARMAM] New publication on Cook Inlet belugas and disturbance

Elizabeth A McHuron emchuron at uw.edu
Thu Jun 8 08:14:01 PDT 2023

Dear colleagues,

My co-authors and I are pleased to announce our new publication on Cook
Inlet beluga whales exploring potential impacts of changes in prey
availability and anthropogenic disturbance on behavior, body condition, and
vital rates.

McHuron, E.A., M. Castellote, G.K. Himes Boor*, K.E.W. Shelden, A.J.
Warlick, T.L. McGuire, P.R. Wade, and K.T. Goetz. 2023. Modeling the
impacts of a changing and disturbed environment on an endangered beluga
whale population. Ecological Modelling 483: 110417.
*Please note there was an error in author names by the journal that is
currently being fixed but is still present in the online version

Climate change and disturbance from human activities are key threats facing
many wildlife populations worldwide. The ability to quantify the effects of
such threats on individual health and population dynamics is critical for
effective management and conservation. We used Stochastic Dynamic
Programming (SDP), a method for implementing state-dependent life history
theory, to explore the impacts of changes in prey availability and
anthropogenic disturbance on survival and reproductive success of Cook
Inlet belugas (*Delphinapterus leucas*, CIB), an endangered and isolated
population in decline. We predicted behavioral decisions (whether to
forage, travel to a new location, or rest) of pregnant CIBs within a
spatially and seasonally dynamic prey landscape. We used those decisions to
explore time-activity budgets and spatial use under a variety of
hypothetical environmental scenarios and estimate the resulting impacts on
body condition and vital rates. In all scenarios, foraging activity was
highest during summer to capitalize on abundant prey, which in the model
was assumed to be eulachon (*Thaleichthys pacificus*) and salmonids (
*Oncorhynchus* spp.). This resulted in large increases in blubber reserves
that pregnant CIBs relied on during October to April when prey was assumed
to be less abundant. Prey availability outside of summer months was still
critical, as it either exacerbated or buffered against reductions in prey
availability during summer months. Spatial predictions of habitat use
indicated that pregnant CIBs should forage in areas used historically that
now appear to be abandoned, suggesting that prey availability alone is
unlikely to explain the recent range contraction of CIBs to upper Cook
Inlet. Reductions in prey availability from late spring to early fall
adversely affected vital rates, but intermittent disturbances that resulted
in lost foraging opportunities, such as those caused by anthropogenic
activities during the ice-free season, had little impact on body condition
or vital rates if prey were abundant during the summer and early fall.
Accurate assessment of the effects of anthropogenic disturbance on CIBs
requires robust data on both disturbances and year-round prey availability,
as intermittent disturbances adversely affected survival and reproductive
success when they occurred in environments with reduced prey availability.
Our model represents an initial effort to fill a critical information gap
for informing CIB management decisions, providing insights into conditions
under which reductions in vital rates might be expected and highlighting
key data needed to increase the applicability of the model to this
endangered population.

Please click here
for limited free access to this article. Feel free to reach out with any
questions or if you need a copy of the publication (emchuron at uw.edu).


Liz McHuron

Elizabeth McHuron, PhD
Research Scientist, UW CICOES
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