A new global review shows that set nets are posing a serious threat to the survival of New Zealand's endangered yellow-eyed penguins. Urgent action is needed to help the species survive.

The Trouble With Set Nets

A global review of penguin bycatch reveals that set nets, the fine nylon mesh used to catch fish by the gills, are posing serious threats to New Zealand's rare penguins, the yellow-eyed penguins or hoiho. In fact, set nets were found to have caused the most penguin deaths, killing an average of 35 yellow-eyed penguins each year.

The trouble with set nets is that diving penguins like the yellow-eyed penguins do not see the wall of mesh netting, so they end up entangled and eventually drown. What's troubling is that this sort of net is being used by 330 commercial vessels in New Zealand and even by recreational fishers.

Conservation Measures On Land And Underwater

According to Dr. Ursula Ellenberg, a penguin scientist from University of Otago who initiated the global review, conservation efforts on land alone will not help save the species from extinction. Given the results of the reviews, she states that saving them from drowning in set nets is the one thing authorities can do to save the species from extinction since there is no quick fix for climate change and habitat loss.

Video surveillance on fishing boats to monitor bycatch is suggested as a possible precautionary measure, but as the situation for the yellow-eyed penguins is so severe, removing set net closures in penguin foraging areas or at least setting them at night may be needed. This would help, not just the yellow-eyed penguins, but other penguins in New Zealand as well.

"Setting the nets at night can considerably reduce the bycatch of penguins since these are visual hunters and mostly forage during daylight hours," said Dr. Ellenberg.

Further, Dr. Ellenberg states that the population of yellow-eyed penguins is declining as there are more and more lone penguins on empty nests after their partners do not return from foraging at sea.

The report is published in Endangered Species Research.

The Treasured Yellow-Eyed Penguins Of New Zealand

Yellow-eyed penguins or hoiho are endemic to New Zealand, and are thought to be one of the world's rarest penguin species. They are considered by the New Zealand Department of Conservation (DOC) as Threatened-Nationally Endangered, which means that the rare species is already facing extinction in the short-term.

Apart from set nets, habitat loss, disease, predation, and human interference are also threats to the species. For instance, when people enter nesting areas, some of the adults delay their return to the nest to avoid interaction, the nesting penguins experience stress, and survival rates of the chicks decline.