Are cormorants destroying fishing?

I was driving near the Warwickshire Avon the other day and noticed several cormorants flying overhead. I must admit that I didn't give it much of an after thought since cormorants are often seen inland during the colder months. However, a day or so later Martin Bowler posted the following via Facebook:

Just been sent this picture along with an incredible story by friend Mike Green. He and a mate witnessed this 30lb carp being killed by three cormorants after repeatedly diving on it. So much for them only eating small fish!

The pictures you see here were taken by a friend of Martin Bowler claiming the fish's death had been caused by three cormorants . The post obviously caused a reaction with a few people claiming the injuries were not consistent with a cormorant attack and blamed a range of other animals such as otters and rats. The witness, Mike Green, has detailed the incident on his website (here).

Anglers have been moaning about the effects of cormorants (plus otters, crayfish, water abstraction, etc) on our native fish stocks and the demise of fishing as a result for quite a number of years. The general public however are largely oblivious to the plight our sport is undergoing. When they switch on to Autumnwatch and the like, they never see fish or get told about the problems experienced in many of the nation's waterways. Instead they are told about the decline in Starling populations or see young otters frolicking. If the angling community is serious about seeing these issues addressed then it needs to make incidents such as the cormorants attack above public knowledge and this is the bit I don't get. Angling has some prominent people to back a campaign such as Ian Botham, Chris Tarrant as well as people like John Wilson, Matt Hayes and Martin Bowler. Surely, rather than highlighting such incidents to the already informed anglers it would be better if the national press, wildlife organisations, TV programmes such as Autumnwatch were made aware of these type of incidents otherwise nothing will change and the moaning will continue.