The Joint Bird Group have produced a leaflet which is designed to inform anglers about cormorant predation issues. This publication simply confirms the facts about the interactions between cormorants and fisheries in a question and answer format and some of these are listed below. Please go to the Other Info. section to print the full leafet.

How many cormorants are there?
It is estimated that there are about 200,000-250,000 pairs in Europe. Around 7,500 pairs nest in the UK, of which 1,500 pairs nest inland (though only four sites hold more than 100 pairs). About 25,000 cormorants winter in the UK, of which 10,000 winter inland.

Why have cormorants increased inland?
Birds of the sinensis race, which is used to nesting in trees, visit the UK during the winter and a small but increasing number remain here to breed. Birds of the coastal race carbo increasingly nest inland. It is not known why this has happened but possible reasons include the creation of many reservoirs and gravel quarries since the 1960s and the stocking of fish in these waters; over-fishing of prey species around the coast; legal protection; and, a reduction in pollutant levels.

Are cormorants protected?
Cormorants are protected under the Wildlife and Countryside Act 1981. Birds cannot be killed, their eggs or nests (when in use or being built) taken or destroyed, except under licence. If cormorants are causing serious damage to a fishery or to wildlife conservation interests, the landowner or manager of a site can apply for a licence to shoot a limited number of the birds as an aid to scaring. See advisory leaflet "Fisheries and the presence of cormorants, goosanders and herons" (WM14) in the Other Info. section or the Licences section.

What do cormorants eat?
In England and Wales, roach and perch are the most numerous prey items while rainbow and brown trout are consumed at put-and-take trout fisheries. Cormorants commonly take fish between 5 and 15 cm (2 to 6 inches) in length, but have been recorded eating fish of over 40 cm (16 inches) and eels of over 60 cm (24 inches) long.

How much fish do cormorants eat?
On average, an adult cormorant requires around 400g - 500g (about 1lb) of food each day although the weight of fish eaten on a particular day can vary considerably. Losses do need to be viewed, however, in relation to the available fish stock, but these calculations are complex and need to take into account natural reproduction.

Can the impact of cormorant predation be reduced?
Yes. A range of measures can be employed to reduce the impact of predation by cormorants, but their effect will vary from one site to another. Disturbance by people is consistently effective, and visual or noise deterrents are most likely to work on stillwaters. These methods are less likely to be useful or effective on rivers. At any given site there may be potential to improve the fisheries habitat, offering fish greater chances of escape from attack, or to change fish stocking policies to make the food source less attractive to cormorants. Ultimately, good quality habitat will assist fish recruitment and survival. Further information in the Management section.

Why not just shoot cormorants?
Shooting cormorants as an aid to scaring can work, but its effectiveness varies. At some sites, shooting, to kill or to scare, appears to make little difference to the number of cormorants present at the site. At others, birds leave for a short while, but return after several weeks.

The cormorants in the UK are part of the European population. Any large-scale cull of cormorants here may simply create a 'gap' for birds from elsewhere in Europe. To make any difference to the cormorant population, it is estimated that 30,000-60,000 cormorants would have to be killed every year throughout Europe. This is not only impractical; it simply would not be acceptable to the general public.