Diving behaviour of yellow-eyed penguins, Port Pegasus/Pikihatiti, Stewart Island/Rakiura, New Zealand

Abstract

Yellow-eyed penguins (hoiho, Megadyptes antipodes) are a Nationally Vulnerable species, restricted in distribution to the lower South Island, Stewart Island/Rakiura, and the New Zealand sub-Antarctic islands. The foraging behaviour of penguins is considered an indicator of marine ecosystems because when breeding they rely on the availability of prey close to their nests. Time–depth recorders were attached to eight nesting hoiho at Port Pegasus/Pikihatiti, Stewart Island. While at sea, hoiho spent 55% of their time diving in water > 3 m deep. Their mean dive depth was 61 ± 6.1 m with mean dive duration 2 ± 0.1 min. Based on bathymetric charts, hoiho could undertake these dives < 10 km from their nesting sites. There was significant variability in hoiho foraging behaviour within New Zealand depending on bathymetry and anthropogenic impacts. Understanding hoiho foraging behaviours could help to determine to what extent they impact on this species' life history and its role as an ecosystem indicator.