Yes Mark, chiefly on the Severn and the Trent. A colony of cormorants moved in to Ironbridge about 6 or 7 years ago, at the time the winter league matches were usually won with around 30 to 40lb of silver fish and there were plenty of back up weights around the same ball park. Within weeks the catch were noticeably smaller and within a couple of years they had reduced to the point where even the best bloke on the best peg would struggle for a bite. Needless to say attendances at the matches dropped off and eventually were cancelled, a short time later the club gave up the lease.
Ironically at around the same time the cormorants disappeared, probably because there was nothing left to eat, only to show up 10 miles away, as the cormorant flies, at Shrewsbury, the next town upstream. And the same cycle has started again.
As for watching them feed well yes, many times in fact, they will swim along with most of their body submerged then dive, only to appear up to a couple of hundred yards away and swallow their prey, those who study this sort of thing reckon a full grown adult bird will eat up to a Kilo of fish a day, it doesn't take a genius to work out that is a hell of allot of fish over a winter.
But they don't just eat fish, I have also seen them systematically remove and eat every duckling from a nest as they hatched, no more than 20 feet from where I was sitting on a carp lake and despite me peppering it with boilies from my catapult it kept coming back every time the mother left the nest and just stretched in and grabbed another one.
Having said all that you cant blame the birds, all they are doing is feeding themselves, if you want someone to blame look towards Brussels and the faceless bureaucrats who are responsible for the common fisheries policy which has resulted in huge factory ships being allowed into coastal waters to hoover up all the fish these birds would normally have fed on to make fishmeal for fertiliser and food for the farmed fish trade.
