corkscrew seal deaths- hideous photo of dead seal:(

[The Woodman]

I've followed this thread from the start with interest having a professional interest in freshwater HEP.

The seal image in the first post must have either been rotated against a sharp edge or have had a sharp edge rotate against it. I am familiar with large fish and eels passing through draught tube impellers and Francis turbines but am struggling to as to what has caused these injuries.

Entrainment in a helical screw device akin to a rotary screw trap employed in fisheries research could result in injuries like this but the proximity of the rotating screw edges to the fixed diminishing cone obviate the result.

[Burko]

The programme also highlights it's due to human interference (commercial fishing) that the Greenland shark has proliferated and changed/adapted its feeding habits.

[ram]

Here's an interesting scientific paper from 1880. Please see the last couple of paragraphs. The GS was common around our shores back then, especially off the Firths of Forth and Tay. NB apart from the possible corkscrew injuries theory, the Sable Island project told us nothing new about the eating habits of this large shark. They were only rediscovering what was known away back then.

Interesting to note too that the Grey seal was extremely rare in Britain back then and virtually absent from the east coast of the country and common seals were regularly hunted for food, so they too were likely to be in limited numbers.

http://www.ncbi.nlm.nih.gov/pmc/arti...00140-0104.pdf

[dangerousdonald]

I'm the real "JAWS" and I'm back ! I'm the Greenland Shark. You humans almost fished me to extinction and now I'm back and I'm going to bite all you windsurfers and folk in blow up canoes.

[ram]

Hi "Jaws," I've just heard there's a Greenland Shark with an inducted propellor fitted to its tail, going up and down the east coast. Apparently this is to give it greater speed, being the sea sloth that it is. One of these illuminicient copepod things has attached to the rear end of the shark and it is this that is drawing the seals to their doom.

We don't want to find out the real cause is man made until after they've made the film!

Just think of the tourist potential for Norfolk after they've made "Ripper?"

[Burko]

Although still speculative until an actual attack has been witnessed, I think I'll go with the theory that's backed up by 17 years of research.

[Lance Morgan]

Sorry to resurrect an old thread but i've just seen the shark ripper programme and the research on the Greenland shark /collagen tear theory. Seems entirely plausible to me seeing that these sharks have been found in large numbers around Norwegian fiords with seal blubber in their stomachs.

[dangerousdonald]

It is quite plausable that it was the greenland shark. I imagine a small shoal of them went up and down the coast (they shoal) causing mayhem then they went on their way else where. I am a harbourmaster on the River Forth. Strange that the boats propelers that was cutting them up last year only worked last year.

[ram]

I think an open mind is called for. As my late Grannie used to say, "Don't put all your eggs in the one basket."

Having recently been part of a group monitoring a grey seal pupping colony in the Firth of Forth, we came across the corpses of two weaned pups which bore the classic corkscrew injuries, starting immediately behind the head and working around the body. These injuries were identical to another corpse we found at the same location two years ago.

I am in now in no doubt that these deaths were caused by the propellers of small fishing boats operating close inshore to the pupping grounds. Therefore I believe that a large percentage of the corkscrew deaths are the result of mechanical means, probably coupled with the natural curiosity of the seals.

However, I also believe that there may be more than one cause for the controversial deaths and so far the Greenland Shark has not as yet got of the hook for its suspected complicity in some of these occurrences.

[bigdave60dog]

This has been a problem for years having killed thousands of seal of Alaska and a good many in Scotland. I don`t think that this is mystery any more. These are usually associated with heavy sea equipment eg large tugs etc which have propellers in tunnels which are much more efficient -more powerful and for much longer that bow thrusters.. The theory is that seals get sucked into one end of the tunnel and come out the other end "Corkscrewed".
I expect that some sea Based wind turbines or something similar are being erected just off shore.
Dave