Have a look at the following :
http://www.scotland.gov.uk/Uploads/Docu ... orants.pdf
This was some work I was involved in some years ago on Loch Leven in Scotland. In part, the population explosion on the Loch was down to the stocking regime which was encouraging more birds to the Loch to feed. What the study did show was the dominance of trout in the Cormorants diet, despite other fish species being present and the potential impact of these birds to a fishery. What I find ironic, was at the time we were studying these Cormorants, under a scientific licence, SNH/RSPB were paying a bounty to the Loch Leven fishery managers to shoot crows to protect the nesting wildfowl and song birds! All this was going on whilst the fishery managers despite years of attempted applications were continually denied a licence to shoot cormorants for the protection of the fishery!!
I'll see if I can find the full report from Loch Leven as it's well worth a read. Needless to say no action was taken despite a wealth of evidence showing the potential impact to a fishery by cormorants. Thankfully the fishery gave up stocking snack sized trout which was nor economically sound nor of benefit to the fishery. Thankfully Loch Leven has since made a recovery to a viable fishery again.
With the recent harsh winters in Scotland we have seen a marked increase in Cormorants feeding inland, as conditions at sea are obviously less than attractive for piscivorous birds. Rightfully or wrongfully they have been attributed to a massive slump in Grayling numbers locally, both on the Earn and Tay systems. I've seen this at first hand with dozens of cormorants working a small section of the River Earn at low water level conditions. As Grayling and spawning salmonids are the only active fish at this time of year then it stands to reason what they are eating.
With an overwhelming amount of evidence in support of the potential damage these birds can cause and skewed population figures from the likes of the RSPB we will always unfortunately be at odds with such large bodies. What I find depressing is that wild fisheries that are managed sensibly and are of ecomonic, ecological and historical importance are allowed to go down the tubes. This is unfortunately just another sorry saga along the lines of Salmon Aquaculture on the West Coast of Scotland and Commercial Salmon netting on the East Coast of Scotland.
but I couldn't find an estimate for the number of European ducks shot/year.
