Penguins follow fishing boat net lines

Fishermen are used to seeing seabirds hovering and swooping over their nets at sea, but New Zealand researchers have found that flightless penguins also trail in the wakes of fishing boats, hoping to catch an easy meal. The three-year study by researchers at the University of Otago found that the endangered yellow-eyed penguin foraged in straight lines for several kilometers by following furrows in the seafloor scoured out by fishing trawlers' nets. "This research is unique as it shows for the first time that not only do flying seabirds follow fishing vessels, but also penguins, with the latter foraging after a trawler has gone through a particular area," lead research Professor Philip Seddon said in a statement Wednesday. The researchers said blue cod and other bottom feeders were likely to forage around the seafloor lines because they were attracted to the marine life stirred up and exposed by the action of the nets being dragged behind fishing trawlers. Many penguins swam to a depth of between 60 and 70 meters to feed during multiple dives over several hours before returning to shore. The penguins could travel up to 120 km in one trip, while foraging in fishing grounds 20 km off the coast of the South Island. "It appears that using the lines for foraging is particularly related to bad breeding years when penguins are more likely to go further out to sea to find blue cod and other bottom feeders," researcher Dr Thomas Mattern said in the statement. However, one of the downsides of foraging around the trawl lines could be that an exclusive diet of blue cod, which tended to be low in nutritional value, could affect breeding.