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In cold blood: evidence of Pacific sleeper shark (Somniosus pacificus) predation on Steller sea lions (Eumetopias jubatus) in the Gulf of Alaska

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Title In cold blood: evidence of Pacific sleeper shark (Somniosus pacificus) predation on Steller sea lions (Eumetopias jubatus) in the Gulf of Alaska
Names Horning, Markus (creator)
Mellish, Jo-Ann E. (creator)
Date Issued 2014-10 (iso8601)
Note This is the publisher’s final pdf. The article was published by the National Marine Fisheries Services Scientific Publications Office and is in the public domain. The published article can be found at: http://fishbull.noaa.gov/1124/horning.pdf.
Abstract Temperature data received
post mortem in 2008–13
from 15 of 36 juvenile Steller sea
lions (Eumetopias jubatus) that
had been surgically implanted
in 2005–11 with dual life history
transmitters (LHX tags) indicated
that all 15 animals died by
predation. In 3 of those 15 cases,
at least 1 of the 2 LHX tags was
ingested by a cold-blooded predator,
and those tags recorded,
immediately after the sea lion’s
death, temperatures that corresponded
to deepwater values.
These tags were regurgitated or
passed 5–11 days later by predators.
Once they sensed light and
air, the tags commenced transmissions
as they floated at the
ocean surface, reporting temperatures
that corresponded to
regional sea-surface estimates.
The circumstances related to the
tag in a fourth case were ambiguous.
In the remaining 11 cases,
tags sensed light and air immediately
after the sea lion’s death
and reported temperatures that
corresponded to estimates of regional
sea-surface temperatures.
In these 11 cases, circumstances
did not allow for inferences on
the species of predator. Among
reported poikilotherm predators
of Steller sea lions, only the Pacific
sleeper shark (Somniosus
pacificus) is known to have body
core temperatures that are near
ambient. The data from this
study indicate that Pacific sleeper
sharks need to be considered
as a possible source of mortality
of juvenile Steller sea lions in
the region of the Gulf of Alaska.
Genre Article
Identifier Horning, M., & Mellish, J. A. E. (2014). In cold blood: evidence of Pacific sleeper shark (Somniosus pacificus) predation on Steller sea lions (Eumetopias jubatus) in the Gulf of Alaska. Fishery Bulletin, 112(4), 297-310. doi:10.7755/FB.112.4.6

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