Environmental footprint from fishing vessels

The ecological footprint of fishing vessels is much deeper and larger than previously thought. This conclusion follows from the results of a study in which the movements and behavior of seabirds were tracked using GPS devices.

A group of scientists under the auspices of the British University of Exeter found that northern cormorants change their usual behavior in response to the appearance of fishing vessels near them, such as trawlers. The patterns of distribution of hunting and feeding zones of these and other marine predators are influenced by literally every little noticeable fishing schooner.

As you know, the northern cormorants Morus bassanus are excellent divers. Their livestock in recent years has been steadily growing and a noticeable impact on this process has the fact that birds eat fishery waste. The study revealed in the diet of birds of prey fish that live much deeper than cormorants can dive.

Scientists from the Centre for Ecology and Conservation at the University of Exeter and the Coastal & Marine Centre at University College Cork (Ireland) analyzed GPS tracking data from 74 cormorants from six nesting colonies in Ireland and compared them with similar data on fishing vessels obtained under the EU monitoring system. (According to the rules, all fishing vessels over 15 meters in length must carry GPS transmitters.)



The information collected showed that the behavior of cormorants is influenced by ships located at a distance of up to 11 kilometers from birds. “Our work has revealed that each fishing vessel has a significant footprint affecting seabirds, in the form of a circle 22 kilometers in diameter, significantly larger than we expected,” said Dr. Thomas Bodey from the University of Exeter.

By studying the interaction of birds and fishermen, the team found that individual cormorants adjust their behavior depending on whether the vessel is actively fishing, as well as depending on the presence of certain fishing gear on board. “The fact that birds react differently to ships depending on whether they are fishing or not, and the type of equipment they are equipped with, shows how sensitive these animals are to the opportunities provided by humans,” said study co-author Dr. Mark Jessopp from University College Cork.

The findings, published June 3, 2014 in the journal Current Biology, help to understand the spatial impact of fishing, which is crucial for marine policy planning, including shipping, offshore development and fisheries.

Co-author Professor Stuart Bearhop from Exeter said: We know that seabirds face many consequences in the marine environment, but we tended to believe that interaction with fishing vessels is a local phenomenon. Our work shows that the impact on the behaviour of these leading predators is much wider.”

Cormorants are the largest seabirds in the UK, able to find food up to 500 kilometers from their colonies. They feed almost exclusively in daylight and rest on the surface of the water at night.

Facepla.net by Phys.org



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