A sorry sight (dead whale) (2 Viewers)

[James Blake]

Hi y'all

There's a recent, weighty scientific report on the effect of sonar on cetaceans here:
http://www.ices.dk/advice/Request/EC/DG%20Env/sonar/agisc05.pdf

Haven't read it all, but here are some of the conclusions:
- much is not known about this issue
- some beaked whale deaths/strandings are certainly caused by sonar
- only high-intensity mid-frequency sonar seems to be a problem
- the exact mechanisms are unclear, but there is some evidence that deep-diving species can suffer 'bends' (this does not seem unlikely to me; before sonar, the number of situations in which cetaceans would need/want to surface very rapidly might well be too small to drive natural selection for the ability to do this safely)
- the number of fatalities caused too far from shore for animals to strand is unknown
- sonar contributes to the rising level of marine noise in general, which is itself a problem
- mitigation measures may be possible
- even given current uncertainties, the effect of sonar on even beaked whales, the most affected group of cetaceans, is almost certainly far less than the effect of bycatch.

best wishes to all
James

 

[Farnboro John]

Hi y'all

There's a recent, weighty scientific report on the effect of sonar on cetaceans here:
http://www.ices.dk/advice/Request/EC/DG%20Env/sonar/agisc05.pdf

Haven't read it all, but here are some of the conclusions:
- much is not known about this issue
- some beaked whale deaths/strandings are certainly caused by sonar
- only high-intensity mid-frequency sonar seems to be a problem
- the exact mechanisms are unclear, but there is some evidence that deep-diving species can suffer 'bends' (this does not seem unlikely to me; before sonar, the number of situations in which cetaceans would need/want to surface very rapidly might well be too small to drive natural selection for the ability to do this safely)
- the number of fatalities caused too far from shore for animals to strand is unknown
- sonar contributes to the rising level of marine noise in general, which is itself a problem
- mitigation measures may be possible
- even given current uncertainties, the effect of sonar on even beaked whales, the most affected group of cetaceans, is almost certainly far less than the effect of bycatch.

best wishes to all
James

Thanks James. A cool response that focuses attention back on the real problem facing the oceans: mankind's rape of the resources therein and casual attitude to the oceanic equivalent of roadkill.

John

 

[Bananafishbones]

Back to the whale in question: Vital statistics are
6.12mtrs long
2-3 tonnes
Probable cause of death dehydration & Liver failure

Info supplied by UK Cetacean Strandings Investigation Programme (CSIP).

Whatever was and is the real killer both in the past and undoubtedly will be again in the future it is a real shame to see such a young whale stranded on a beach. Just hope I dont witness one again
Dave

 

[mathew1208]

In the paper they believe the bottlenosed whale was pushed this way due to the new sonners used by the navy they believe we could see some more on our beaches they new sonners are very powerful and whales can hear them from many miles away so we could all see some sad sites soon such a shame the navy are in scotland at the moment on a massive exercise so finger crossed we see no more

 

[Bananafishbones]

Mmmm
It seems there maybe more than a hint of truth in the Sonar theory then. Athough this is very new to me and I may seem very naive to the subject, I can see why this could be a factor in whale deaths.

there are obiously still 2 camps on this, even in the papers!!

Still very sad

 

[Farnboro John]

In the paper they believe the bottlenosed whale was pushed this way due to the new sonners used by the navy they believe we could see some more on our beaches they new sonners are very powerful and whales can hear them from many miles away so we could all see some sad sites soon such a shame the navy are in scotland at the moment on a massive exercise so finger crossed we see no more

If its any comfort most operational use of sonar relies on passive systems as the moment you start emitting you pinpoint yourself to every passive sonar in the ocean. The big emitters are for last-ditch when you know something is out there but can't hear it (submariners often boast their boats are quieter than the background noise of the ocean).

Use of emitting sonars is therefore kept to a minimum.

John

 

[cliffben]

Could get sadder...

Mmmm
It seems there maybe more than a hint of truth in the Sonar theory then. Athough this is very new to me and I may seem very naive to the subject, I can see why this could be a factor in whale deaths.

there are obiously still 2 camps on this, even in the papers!!

Still very sad

Thankfully most of the people in this forum are asking the right questions and thinking before they do so. Just a couple of points.

Bycatch is a seperate question and yes dolphins do get caught whilst they are hunting the same fish (Mackerel, Bass etc) as fishermen.These tend to be Common and Bottlenose Dolphins and Porpoises in the UK and N Europe.

Beaked Whales are specialist vertical feeders diving incredibly deep to find their food. They live in the deeper parts of the sea where submarines would also try and hide. Although anti submarine warfare is designed to huntand kill submarines rather than Beaked Whales it has the same effect.

Northern Bottlenose Whales (sometimes and historically referred to as North Sea Whales) were considered to be one of the commoner species of BW, but were hunted to commercial extinction in northern Europe by the Norwegians in the early part of the C20. presumably their numbers may be recovering but I fear that this new techno warfare may well be as big a threat to their and other cetacean species viability as whaling was in the last century.

We all have our own views as to what our governments priorities should be with regards to defence and I am prepared to leave that to one side. What I would say is that if we destroy the sea and its biodiversity at the rate we are doing, big boys toys will not save us.

I spend a lot of time at sea as a semi professional cetacean observer/recorder and am seeing large amounts of Risso's Dolphins in recent weeks here in the Southern Irish Sea. This morning between Rosslare (Ireland) and Fishguard (Wales) we spotted four separate pods containing vulnerable slow moving mothers and small calves, around 50 animals in total. This is not massively out of line with previous years but there does seem to be quite an increase. Why? we dont know, in fact what we dont know about these majestic creatures is a lot more than we do know. Untill we started doing our surveys, nobody suspected such concentrations of these poorly reported animals. It may be the same elsewhere around out coasts. In the past few months, we have recorded superpods of Common Dolphins, Fin Whale concentrations and as well as large numbers of breeding Risso's (see http://whaleswales.blogspot.com/2009/08/this-is-some-film-i-took-of-fin-whales.html)

They may have been attracted by a food surplus or favourable climatic conditions or displaced by something awry, wherever they have appeared from. We dont know and there is a huge amount of the British and particularly Scottish Coast about which we have little or no real idea of cetacean populations or usage.

Operation Joint Warrior is taking place currently from the east coast of Scotland right round to the northern Irish Sea. Lets hope there will be no more sorry sights, though I rather suspect there may be.

 

[Bananafishbones]

Cliffben (and Farnboro John) you have made my initial thread of an observation somewhat of a real learning experience for me if no-one else.
I am still confused by the whole topic but can really see why we could have a problem.
The finding of the dead whale has inspired me to gain more knowledge on the subject and both views will be taken into account until i have gained that knowledge. I have been in contact with a guy in Poland regarding his work on Cetaceans, see I am learning!!

Could make my trips to the coast even more inspiring

Regards
Dave

 

[rockfowl]

http://www.wildlifeextra.com/go/news/whales-sonar009.html

 

[Mysticete]

Not much to add to this thread since I got in late, but I can certainly confirm that marine mammals can get the bends, although this doesn't always kill them. There are many records of Sperm whales with bone lesions which come from surfacing too quickly, and we even have examples of fossil whales with evidence from the Bends. Beaked whale diving patterns, at least in those animals which have been tagged, show regular routine timing of speed of ascent and descent, and this is probably related to prevention of the Bends.

 

[James Blake]

The Seawatch Foundation has posted a summary of the recent spate of UK beaked whale strandings, with some discussion of possible causes:
http://www.seawatchfoundation.org.uk/news.php

 

[Bananafishbones]

The Seawatch Foundation has posted a summary of the recent spate of UK beaked whale strandings, with some discussion of possible causes:
http://www.seawatchfoundation.org.uk/news.php

Cheers for the link James