Fishing Boats Can Attract Seabirds From 22 Km Away

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Fishing Boats Can Attract Seabirds From 22 Km Away

Anyone who’s ever been aboard a fishing boat has likely noticed the hoards of seabirds circling overhead, hoping for a share of the catch. It might seem that birds are randomly attracted to boats passing by, but researchers report in today’s issue of Current Biology that seabirds, specifically northern gannets (Morus bassanus), are much savvier. The scientists attached GPS-collecting tags to 74 gannets—large, black-and-white seabirds found in the North Atlantic—from six colonies around the British Isles and followed their movements for 2 months. All the gannets were rearing chicks, and so were regularly foraging at sea. The team then compared the birds’ travels with those of fishing vessels at least 15 meters in length, using data from the vessel monitoring system of the Irish exclusive economic zone. The scientists’ analysis shows that the gannets readily spotted the difference between trawlers that were actively fishing and those that were steaming or merely drifting. The birds preferred to forage near the active fishers and traveled away from those that weren’t busily fishing; they also foraged near boats that weren’t trawling if those aboard were processing their catch and discarding scraps. The boats have a far greater influence on gannets than scientists realized, affecting their foraging decisions over a 22-kilometer area—the first time that researchers have estimated how much a single fishing vessel affects other marine predators.

Posted in Biology, Plants & Animals