New feeding technique of Great Cormorants Phalacrocorax carbo sinensis at beam trawlers

Since the mid 1980s, following a marked range expansion and dramatic population growth, continental Great Cormorants Phalacrocorax carbo sinensis, increasingly use Dutch coastal waters as a feeding area. Fishing Great Cormorants are now commonly seen at sea within 15 km of the nearest coast and small numbers disperse further out to sea. Small beam trawlers, mainly targeting Brown Shrimp Crangon crangon, are the dominant fishery of these waters and Great Cormorants were soon seen to attend these vessels. Recent observations indicate that, in contrast to other ship-following seabirds, Great Cormorants forage continuously during the towing of nets, even when no discards are produced on board. It is suggested that these birds prey on disturbed fish or other prey, just behind the moving nets that rupture the bottom. This feeding technique has not previously been observed in any species of seabird in the North Sea.