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<DIV class=articleTitle><FONT face=Arial size=3>Journal of Applied
Ecology</FONT></DIV>
<DIV id=publishedOnlineDate><SUP><FONT face=Arial size=3>Article first published
online: 7 OCT 2010</FONT></SUP></DIV>
<DIV id=doi><SUP><FONT face=Arial
size=3>DOI: 10.1111/j.1365-2664.2010.01888.x</FONT></SUP></DIV>
<DIV><SUP><FONT face=Arial size=3></FONT></SUP> </DIV>
<DIV class=articleTitle><SUP><FONT face=Arial size=5>Replicating necropsy data
without lethal collections: using ultrasonography to understand the decline in
northern fur seals</FONT></SUP></DIV>
<DIV id=cr1><FONT face=Arial size=3><SUP>J. Ward Testa1,2,*, </SUP></FONT><FONT
face=Arial size=3><SUP>Gregg P. Adams3, </SUP></FONT><FONT face=Arial
size=3><SUP>Don R. Bergfelt4, </SUP></FONT><FONT face=Arial size=3><SUP>Devin S.
Johnson1, </SUP></FONT><FONT face=Arial size=3><SUP>Rolf R. Ream1,
</SUP></FONT><FONT face=Arial size=3><SUP>Thomas S. Gelatt1</SUP></FONT></DIV>
<DIV><FONT face=Arial><SUP>1</SUP> National Marine Mammal Laboratory, Alaska
Fisheries Science Center, 7600 Sand Point Way NE, Seattle, WA 98115-6349,
USA<SUP>2</SUP> Biological Sciences Department, University of Alaska Anchorage,
3211 Providence Drive, Anchorage, AK 99508-4614, USA<SUP>3</SUP> Western College
of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon
SK S7N 5B4, Canada<SUP>4</SUP> U.S. Environmental Protection Agency, Office of
Science Coordination and Policy, 1200 Pennsylvania Ave., NW, Washington, DC
20460-0001, USA*Correspondence: J. Ward Testa, E-mail: <!--TODO: clickthrough URL--></FONT><A title="Link to email address"
href="mailto:ward.testa@noaa.gov" shape=rect><FONT face=Arial
color=#007e8a>ward.testa@noaa.gov</FONT></A></DIV>
<H3><FONT face=Arial>Summary</FONT></H3>
<DIV class=para>
<P><FONT face=Arial><B>1.</B> Many valuable contributions to the biology and
conservation of harvested or previously harvested species have come from
examination of specimens obtained by lethal collections. The northern fur seal
<EM>Callorhinus ursinus</EM> on the Pribilof Islands, Alaska, has a long history
of exploitation, including a large (>320 000) experimental harvest of
females from 1955 to 1968 when the population was at a peak (∼2 million
seals). The decline caused by this harvest was followed in 1977 by another major
decline, apparently unrelated to harvest, that has recently
accelerated.</FONT></P></DIV>
<DIV class=para>
<P><FONT face=Arial><B>2.</B> To obtain current reproductive data that could be
compared directly with historic estimates, we used imaging ultrasonography to
estimate pregnancy rate in 171 adult fur seals captured on St. Paul Island,
Alaska, in November, near the end of embryonic diapause. A modified logistic
regression of pregnancy by date was used to estimate asymptotic pregnancy rate;
a Bayesian hierarchical model based on date and size of embryonic vesicle was
also used to account for pregnancies that were not detectable on the date of
examination.</FONT></P></DIV>
<DIV class=para>
<P><FONT face=Arial><B>3.</B> Pregnancy rate was high [0·85
(SE = 0·05), 0·88 (SE = 0·05) or 0·92 (SE = 0·04),
depending on method] and there was little statistical support for the hypothesis
that the current pregnancy rate is lower than the pre-decline rate (0·84,
SE = 0·012) or contributing significantly to the present
decline.</FONT></P></DIV>
<DIV class=para>
<P><FONT face=Arial><B>4.</B> <EM>Synthesis and applications.</EM> Further study
on intrauterine losses and pupping rates is necessary and ongoing, but
reproductive ultrasonography provided an early comparative assessment important
for the conservation management of this fur seal stock. It narrows the search
for demographic and ecological causes of the population decline and allows
research priorities to evolve in response to the likelihood of those causes. The
field and analytic methods described have application to population assessments
of other mammalian species, including those considered threatened or serving as
ecosystem indicators.</FONT></P></DIV></FONT></BODY></HTML>