[MARMAM] new article - Pseudorca echolcation, bycatch and depredation

T. Aran Mooney amooney at whoi.edu
Tue Aug 11 06:33:11 PDT 2009



Dear Colleagues,

The following article was recently published in the Canadian Journal of Zoology:

Mooney, TA, Pacini, AP, and Nachtigall, PE.  2009. False killer whale (Pseudorca
crassidens) echolocation and acoustic disruption: Implications for long-line
bycatch and depredation. 87: 726-733. Canadian Journal of Zoology.

Abstract: False killer whales (Pseudorca crassidens (Owen, 1846)) depredate fish
caught by the North Pacific pelagic longline fishery, resulting in loss of
target species catch and the whales themselves becoming bycaught. This
incidental take of false killer whales exceeds sustainable levels. In an effort
to address a potential solution to reducing this depredation and bycatch, we
tested an acoustic device designed to deter false killer whales from
approaching longlines by reducing the whales’ echolocation performance
capabilities. The device produced a series of complex, broadband signals (1–
250 kHz) at high intensity levels (up to 182 dB). In the experiment, a trained
false killer whale was asked to detect a target in the presence or absence of
the acoustic device. Baseline performance capabilities were 95% correct
responses. Initially, the device reduced the whale’s echolocation performance
to chance levels. However, subsequent sessions demonstrated improvement in
echolocation performance up to 85%. This improvement was likely a result of
behaviorally adapting to the task and a decrease in the source level of the
echolocation ‘‘disruptor.’’ The results underscore the challenges
in using acoustic devices to reduce depredation and bycatch, and demonstrate the
need for concern regarding anthropogenic noise levels and effects on odontocete
echolocation capabilities.

A pdf may be downloaded from
http://pubs.nrc-cnrc.gc.ca/rp-ps/inDetail.jsp?jcode=cjz&vol=87&is=8&lang=eng

pdf copies or further information are also available by emailing:
amooney at whoi.edu



T. Aran Mooney
Postdoctoral Scholar
Woods Hole Oceanographic Institution
(508)289-3714 (w)
(518)339-1151 (c)


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