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SpringHeeledJack
17th Aug 2010, 17:21
'Corkscrew' deaths of seals off British coast baffling scientists | Mail Online (http://www.dailymail.co.uk/news/article-1303721/Corkscrew-deaths-seals-British-coast-baffling-scientists.html)

For the perusal of the great and good minds of pprunelandshire. One chap said that it was reminiscent of being put through a bow thruster on a submarine or suchlike, but whatever it is it's an unusual injury for any unfortunate sea-creature. Anyone wish to venture a theory ?



SHJ

Cheerio
17th Aug 2010, 17:36
Looks like the sort of thing you might get if tangled up in an auger (http://www.universal-augers.com/), perhaps one doing ground surveying or drilling for offshore wind turbines?

Caboclo
17th Aug 2010, 17:39
QM2's podded engines? Prolly not, can't think why they would cause different injuries than any other prop. Maybe a new-fangled method of propulsion on some Russian sub, a la Red October.

tony draper
17th Aug 2010, 17:45
Yer obviously some kind of ducted prop.:uhoh:

RegDep
17th Aug 2010, 17:53
Wonder why not a fast (and sharp) propeller. Seen fish who have been hit by an outboard boat engine propeller and the pattern is the same. This would require a bit bigger blade, but..... Does not need to be ducted or something.

11Fan
17th Aug 2010, 17:53
Pillsbury Seal Biscuits?

tony draper
17th Aug 2010, 17:59
Would have thought a rotating naked prop would just produce a series of parallel slashes,a ducted configuration would trap the poor critter betwixt the duct wall and the blades pulling it through and rotating it at the same time producing a continuous helical wound like the one in the photo.
:uhoh:

RegDep
17th Aug 2010, 18:09
Purely guessing, but I believe the prop and the rushing water would make the fish/seal rotate while it goes past. Wouldn't the prop suck the animal closer along with the water, too? Will not start an argument. The fish wounds were helical, though. Made me think then.

tony draper
17th Aug 2010, 18:12
Summat like this be the culprit.
http://i11.photobucket.com/albums/a194/Deaddogbay/Brosen_bowthruster_pharos.jpg

BAMRA wake up
17th Aug 2010, 18:13
It's summer, so possibly suction dredgers clearing sand and silt from North Sea harbours. Blame the Dutch, who are the experts, not the French. Seals are opportunists, they're probably attracted by the shell fish exposed by the dredging and get sucked against the cutter head. They're not called 'harbour seals' for nothing.

http://www.cnsm.csulb.edu/departments/geology/people/bperry/Geol303photos/shoreline%20modifications/DiagramCutterHeadSuctionDredgeSCHarbor.jpg



Recall a similar 'mystery' a few years back in Scotland that got the scientists publicity and funding: decapitated seals washed ashore. The scientists blamed rogue elements in the inshore fishing industy. Turned out it was Killer Whales, which can be relatively common in the North Sea at times, and it was the fishermen who witnessed them playing with their prey, cat-like, and biting the heads off. It appeared to be a process of teaching their young to hunt.

grizzled
17th Aug 2010, 18:29
Evidence of deficiencies in the prototype Eskimo Large Scale Seal Skinner and Blender?

lomapaseo
17th Aug 2010, 18:48
Was there a Benihana japanese resturant in the vicinity ?

or:

It has to be a ducted prop as Drapes shows,

the distance between slices being a function of the prop speed vs the seal's speed through a confned direct line space. Bird slices through a ducted prop look the same (at low rotational speeds)

Gentleman Jim
17th Aug 2010, 18:56
My money is with BAMRA (for now;))

tony draper
17th Aug 2010, 19:01
Watched a prog about Manatees in the Florida waterways and a lot of them had prop scars on their backs from out board motors,they were just three or four parallel slahes, I think a critter would be pulled into the prop on the input side and thrust away from it by the propwash on the output side so summat had to held them agin the rotating blade.
:uhoh:

Caboclo
17th Aug 2010, 19:04
Dredges and bow thrusters have been around for a while. Why are these injuries just now showing up?

Gentleman Jim
17th Aug 2010, 19:17
new designs maybe?

tony draper
17th Aug 2010, 19:41
hmmm yer that is a bit of a puzzle,perhaps nobody noticed before, they were just another dead and decomposing seal washed up,then someone did notice the odd wounds and from thence they started looking for and finding them,tis one's observation tha untill one starts looking for summat it seldom shows up.
Speaking of decomposing seal carcasses,it is unwise to allow a Jack Russel to roll around on one,to us the smell is disgusting to them it is channel No 5.
Especially if you and said JR are staying in a Caravan
.:uhoh:

Noah Zark.
17th Aug 2010, 19:54
Looking at the picture, it seems that the creature has been rotated and moved along at the same time. the "pitch" (as in airscrew pitch) of the wound is odd.
I'm sure that if they had come into contact with thrusters, etc., they would have been just chopped up.

sisemen
18th Aug 2010, 01:26
Whatever is the cause they look well screwed.