The Sea Mammal Research Unit at St Andrews has released its preliminary findings of investigations into the causes of the recent spate of 'corkscrew' injuries to seals. There's a detailed pdf you can download here.
I'm not going to get all smug and say 'I told you so', but their findings point to some sort of ducted propeller system on ships operating in shallow coastal waters. They say they have eliminated most other possibilities include the effects of fisheries, deliberate killing, the effects of illegal traps and predation by killer whales or sharks.
I suppose the challenge now is to find the ship(s) responsible and get some sort of guard fitted pronto.
UPDATE: Despite a TV documentary suggesting it's Greenland sharks, the shark scientists themselves say it's ducted propellers - see here. It's beginning to look as if it's ultimately the stampede for useless windfarms that has caused these seal deaths. The eco-loonys have a lot to answer for, but it will be years before we understand the full extent of the damage they are doing.