The Department of Conservation says the breeding season for yellow- eyed penguins this year is a disaster.

The study said set nets were estimated to kill on average 35 yellow- eyed penguins each year.

Avian diptheria has killed one in three yellow- eyed penguin chicks hatched at two north Otago colonies this year.

Photo: Supplied DoC, the Yellow- eyed Penguin Trust and other key groups have been counting nests for the last month.

Yellow- eyed Penguin Trust general manager Sue Murray said it was exciting having experts from all corners of the globe.

Yellow- eyed penguins get all sort of problems, he said, and mysteriously losing about 50 breeding adults was a big blow.

The review identifies the endangered hoiho, or yellow- eyed penguin, as one of three penguin species most under threat by fishing equipment.

It identified the endangered hoiho, or yellow- eyed penguin, as one of three penguin species most under threat by the fishing equipment.

More than half of the remaining yellow- eyed penguin population breeds on the uninhabited Auckland Islands and Campbell Island, south of Bluff.

The Yellow- eyed Penguin Trust's conservation science advisor, Trudi Webster, says a whole suite of things have contributed to the population crash.

Conservation Minister Eugenie Sage has released a draft strategy to recover yellow- eyed penguin populations, following a series of poor breeding seasons.

Set nets are a major cause of penguin deaths, affecting most of the world's species including New Zealand's hoiho, or yellow- eyed penguin.

Yellow- eyed Penguin Trust general manager Sue Murray said, this year, the nest numbers were slightly better further south on predator-free Codfish Island.

The Hoiho, or the yellow- eyed penguin, won this year's at times fiercely competitive campaign, pipping the kākāpō in a close run race.

Forest and Bird members dressed in yellow- eyed penguin suits have held a creative protest down the main street of Balclutha in South Otago.

A volunteer ranger says the Department of Conservation is putting the yellow- eyed penguin at risk to build a capark in Southland's Curio Bay.