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Old 22 September 2004, 14:57   #1
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sonar killing whales

http://news.bbc.co.uk/1/hi/sci/tech/3680086.stm

Just read this article that may be of some interest - it is not a new idea - people have been going on for some time now about the sheer amount of noise undersea causing problems to marine mammals.

It is quite possible a boat with sonar(fishfinder) that is being used to protect dolphins could be causing them more harm than people on jetskis alleged to be chasing them!

Most of the probs come from military stuff - the Irish sea is littered with hydrophones and sonar arrays used for watching Russian subs.

Although the military get the blame all sonar is of a VLF that could cause probs - maybe an idea to be cautious with the use of fishfinders etc.
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Old 22 September 2004, 15:01   #2
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Just had an interesting thought - the prob isn't just from sonar but all VLF sounds - even big ships slow revving props - maybe at last a good excuse for a high revving 2 stroke!!!!
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Old 22 September 2004, 15:54   #3
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I will be killing a lot more if I run aground because I switched the sonar off.
Personally I consider a fishfinder an essential piece of equipment to operate a small boat around the UK waters, and the more power the better.

Pete
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Old 22 September 2004, 16:42   #4
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Quote:
Originally Posted by Pete7
I will be killing a lot more if I run aground because I switched the sonar off.
Personally I consider a fishfinder an essential piece of equipment to operate a small boat around the UK waters, and the more power the better.

Pete
That's a bit of a 'george bush' attitude!

You could buy a chart & gps, then you'd actually know where the shallow bits are!
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Old 22 September 2004, 16:54   #5
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And you feel a chart is accurate then ? or just an interpritation of what someone thinks is there. Anyway speed boats don't carry charts do they ? only raybans and Fosters Tony said.
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Old 22 September 2004, 18:09   #6
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Fosters aint a lot of good to me!
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Old 22 September 2004, 18:15   #7
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I think the quote was "raybans and condoms"
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Old 23 September 2004, 03:28   #8
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Mean While back at the point sorry Jonney
It always make me smile when the expets say that all the noise hurts the cetaceans - it probbably does I'm no expert.
But why do they come and play with ships, I've seen dolphins and whales playing with seismic survey vessels even rubbing themselves on the airgun arrays whiles they fire (the air guns release a slug of high pressure air to create an acoustic pressure and its reflections are measured).
Surly if it hurt them they would leave and not stay and play?

Now we had to slowly increase the presure so if they want to leave they can before it gets to noisy and have to stop if we see any cetaceans.
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Old 23 September 2004, 07:25   #9
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Mean While back at the point sorry Jonney
It always make me smile when the expets say that all the noise hurts the cetaceans - it probbably does I'm no expert.
But why do they come and play with ships, I've seen dolphins and whales playing with seismic survey vessels even rubbing themselves on the airgun arrays whiles they fire (the air guns release a slug of high pressure air to create an acoustic pressure and its reflections are measured).
Surly if it hurt them they would leave and not stay and play?

Now we had to slowly increase the presure so if they want to leave they can before it gets to noisy and have to stop if we see any cetaceans.
Maybe it's the same reason moths are attracted to a flame? Curiosity killed the cat and all that!

Seriously though I don't think it is localised noise that's the problem but the overall background noise that confuses them.
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