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Re: Sperm whales (Physeter macrocephalus) interaction with long line


Huseyin Ozbilgin <[log in to unmask]>


Scientific forum on fish and fisheries <[log in to unmask]>


Thu, 22 Feb 2001 01:01:31 -0800





text/plain (1 lines)

Hello Stephen,
This is Huseyin from Izmir, Turkey. Hope all is well
with you. Do you know yet how long more you are in
Plymuth? All is well with me, There is possibility
of visiting Aberdeen after four years this summer. I
miss Scotland and the friends overthere so much.

We have an MSc student who wants to do a thesis on
Acoustic repellents to reduce dolphin bycathes in
pasive fishing gears. She is not around yet and she is
not my student. Therefore I dont exactly know, how
much she knows about the subject. All I know is that
she is very keen. So I would be happy if you forward
me the directly replied comments to you on this
Warmest wishes.

--- Stephen Cotterell <[log in to unmask]>
wrote: > Greeting Fish-Sciers, Fish-ecologyers, and
> Biology Forum subscribers
> This morning I've had an interseting conversation
> with a Canadian fisherman
> regarding a potentially very serious bycatch
> problem.
> He's a longliner working out of a British Columbia
> port, and fishes quite deep,
> around 300 ftm I seem to remember. His problem is
> that when he hauls his gear
> he finds its been striped by sperm whales. He
> certain it is sperm whales
> because he's seen them when hauling and indeed he's
> had one entangled in his
> back line, which subsequently died.
> I am certianly no expert on this, but he has heard
> of some acoustic work going
> on in this lab and approached me in the first
> instance.
> I beleive he's looking for an acoustic device to
> keep away the sperm whales
> when hauling. He reported no problem when shooting
> his gear so it seem likely
> that its the struggling of the lip caught fish which
> is attracting the whales,
> though we didn't discuss which species of fish he's
> catching, he said after a
> six hour set they are still very much alive. The
> depth may mean that this
> sound is propogated a great distrance. I cannot
> remember exactly how deep is
> the sofar layer. Also, the boat's echosounder may
> play a part in attracting
> the whales to the area but he said this is running
> all the time. I'm aware
> that sperm whales use echolocation to find prey so
> perhaps a generated signal
> which interferes with this on a local scale may be
> useful. I also suggested he
> turnes off his echosounder when hauling may be
> useful, though even the noise of
> the hauler pulling up the line could attract the
> whales. Does anyone know?
> I'd imagine that sperm whales use quite low
> frequency sounds to communicate but
> perhaps higher frequency sounds to echlocate as they
> get closer to their prey.
> I wouldn't imagine that sperm whales are messy
> eaters and also that they exist
> soley on a diet of giant squid. Does anyone know
> what is the frequency range
> of sperm whales? Which sounds accompany different
> bahaviours? And has anyone
> tried blocking sperm whale's echolocation?
> Maybe there is another apporach intirely. I'm aware
> of the electrical shark
> repellent systems used by divers. It might be
> possible to discharge a current
> through the fishing gear to deter the whales, but
> I'd imagine the sensory
> systems of sharks and whales to be very different
> and the practicalities of
> discharginging sufficient current might leave little
> room on a fishing vessel
> for the catch and put in jeopardy the lives of the
> crew!
> This is a serious request for information. I said
> I'd pass on any thoughts
> generated by this message. Please feel free to
> discuss this but it is probably
> best if you contact me directly. I'll post a full
> set of contributions if and
> when I get something.
> With thanks
> Stephen
> -Stephen Cotterell
> -Fishery Science Lab
> -Rm 4 22 Portland Square
> -Institute of Marine Studies
> -University of Plymouth
> -Drake Circus
> -PL4 8AA
> -Tel +44 (0)1752 232411
> -Fax +44 (0)1752 232406
> -e-mail [log in to unmask]
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Huseyin Ozbilgin
Ege University,
Fisheries Faculty,
Bornova, Izmir, 35100, Turkey
Tel 00905327061977
Fax 00902323883685

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