Cormorants Phalacrocorax carbo as fish predators: An appraisal of their conservation and management in Great Britain Original Research Article

The breeding population of cormorants Phalacrocorax carbo has expanded from 6 400 in 1969–1970 to 7 200 pairs in 1985–1987 and has probably benefited from protection under the Wildlife and Countryside Act 1981. The available studies of cormorant diet show that they exploit a range of fish species according to locality and season but often concentrate on locally dominant species. No study in Britain (or Ireland) has accurately quantified cormorant losses to fisheries, and the significance of depredation by them therefore remains unclear. A wide variety of methods to protect individual sites against cormorants is available. Most remain untested in British situations, and many may be impractical at some large waters where cormorant predation is seen to be a problem. Shooting to reinforce scaring is regarded as a favourable option by the UK Government and is exercised mainly on Scottish river fisheries. Unlicensed control is probably significant in some localities.