Research Projects >Reproductive
Parameters of Alaskan Sea Otter in Regions of Population Increase and
Decline
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Reproductive Parameters of Alaskan Sea Otter in Regions of Population
Increase and Decline
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Reproductive
parameters of currently declining sea otter populations in western Alaska,
will be estimated and compared to those in increasing populations in the
late 1960s.
Populations of marine apex predators have declined
dramatically within western Alaska over the past two decades. One hypothesis
for the ongoing decline is increased predation; in this scenario, life
history theory predicts a younger age at first reproduction and increased
reproductive rates.
What
Researchers hope to learn:
A careful examination of reproductive tracts of sea otters collected
in different regions and time periods provides an excellent opportunity
to explore how reproductive parameters interact with population trajectories
and may shed light on why sea otters and other apex predators declined. |
Project Outline:
The study will estimate current fecundity rates, age at first reproduction,
and fetal sex ratios in sea otters in increasing (Southeast Alaska), stable
(Southcentral Alaska) and declining (Western Alaska) populations. Reproductive
parameters will be compared to those determined in the late 1960s and
early 1970s when populations were increasing to test the hypothesis that
reproductive parameters have changed in conjunction with shifts in population
trajectories.
The study will rely on carcasses sent by native hunters
to the US Fish and Wildlife Service (USFWS) or The Alaska Sea Otter and
Sea Lion Commission (TASSC) for biosampling. All reproductive tracts (uteri
and ovaries) are collected and preserved as part of this program. These
samples archive the recent reproductive history of a large number of female
sea otters, and can be used to assess reproductive status of otters from
different areas of Alaska. In addition, samples collected by wildlife
biologists in the late 1960s and early 1970s, when the populations were
increasing in many areas, exist and can be used for comparative purposes.
Principle Investigators:
Jennifer Burns , University of Alaska Anchorage
Verena Gill, U.S. Fish and Wildlife Service
Collaborating Investigators:
Jim Bodkin, US Geological Survey
Melissa Miller, California Department of Fish and Game
The Alaska Sea Otter and Steller Sea Lion Commission
Funding Source:
NOAA and the North Pacific Marine Science Foundation
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