Cormorants versus fisheries

Every winter thousands of birds migrate from the Czech Republic for a warmer climate but at the same time thousands more migrate to this country from the north, among them, cormorants. These protected birds have now become a big problem for local fisheries.

Cormorant, photo: Sławek Staszczuk, CC BY-SA 3.0 Unported

The migration of cormorants takes place in October and November and then again in March and early April. However in recent years a growing number have taken to wintering in the Czech Republic. This year there are an estimated 8,000 of them predominantly in the eastern part of the country and fishermen claim that these protected birds are depleting their fish stocks and causing losses worth millions of crowns. Here's how one fisherman puts the problem:

"The cormorants not only catch a vast amount of fish but they injure others in the process and an injured fish - even if it manages to escape - is almost certain to die in the winter months. Those that survive the winter, generally succumb to disease in the spring."

A single cormorant eats a kilo of fish a day and in some areas there over 1,200 of these birds feeding on the fish in local lakes and rivers. Fishermen say that all attempts to scare these birds away have failed and they've asked to be allowed to shoot them in order to reduce their numbers and make the flock move on to a different locality. The local authorities have now given them the green light to do so - on condition that they only shoot at flocks of over 50 birds and do not kill more than a few of them.

Cormorants, photo: J. M. Garg, CC BY-SA 3.0 Unported

The decision has evoked protests both among the public and environmentalists. Moreover there are cases abroad where several hundred cormorants have been killed only to be replaced by hundreds of others.

Petr Musil from Charles University is an expert on cormorants.

"Shooting is the easiest solution but it is a solution that works only on local scale, it does not affect the number of birds on a regional or country scale."

So if the fish is there other cormorants will arrive to feed on it...

"Yes, because central European waters - fish ponds, fish pond systems and rivers are very rich in fish stocks which are mostly artificial, mostly introduced by people and they are a very suitable habitat for migrating and wintering cormorants."

Is there a solution to this problem?

Cormorants, photo: Eva-Maria Kintzel, CC BY 3.0 Unported

"It is not easy to find a solution which will be acceptable for fishermen, nature protection authorities and NGOs. We are now working on an extensive pan-European project which is an inter-disciplinary approach to diminishing cormorant-fishery conflicts in Europe. One aim is to diminish the conflict between cormorants and fisheries and the second is to improve the level of education of people and teach people about the importance of predators in the local landscape. Predator species like cormorants play an important role in Nature."

So how do you reduce the conflict between fisheries and cormorants?

"For example by improving the river-line habitats, most rivers are recently canalized, they have artificial shores, they lack various forms of natural refuge for the fish from predators."