See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/329075802 New Zealand penguins - current knowledge and research priorities Preprint · November 2018 CITATIONS READS 0 705 2 authors, including: Thomas Mattern University of Otago 58 PUBLICATIONS 620 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: The Tawaki Project - Studying the marine ecology of New Zealand's forest penguin View project Conservation of penguins View project All content following this page was uploaded by Thomas Mattern on 12 April 2019. The user has requested enhancement of the downloaded file. New Zealand penguins - current knowledge and research priorities Thomas Mattern Kerry-Jayne Wilson Global Penguin Society West Coast Penguin Trust [email protected] [email protected] A report compiled for Birds New Zealand, July 2018 Index Introduction ................................................................................................... 2 Yellow-eyed penguin / hoiho (Megadyptes antipodes) ................................. 4 Little (blue) penguin / kororā (Eudyptula minor) ......................................... 36 Fiordland penguin / tawaki (Eudyptes pachyrhynchus) ............................... 73 Snares penguin (Eudyptes robustus) .......................................................... 108 Eastern Rockhopper penguin (Eudyptes filholi) ......................................... 136 Erect-crested penguin (Eudyptes sclateri) ................................................. 159 Mattern & Wilson – New Zealand penguins: current knowledge and research priorities Introduction The New Zealand region is a hot spot for seabirds and hosts six of the world’s eighteen penguin species; of these, four are endemic species that occur only in New Zealand. Despite this regional species richness and New Zealand’s reputation for international leadership in conservation, very little is actually known about our penguins; compared to most other non- NZ penguin species, most New Zealand penguin species are poorly researched (Figure 1). Figure 1. Threat status and state of knowledge of the world’s penguin species. New Zealand species rank highly (five out of six endangered or threatened) but are among the least researched. Note that the majority of research on Little penguins was conducted in Australia and it has recently been suggested that the Australian penguins are a different species to most little penguin populations in New Zealand. Similarly, almost all of the research conducted on yellow-eyed penguins occurred on the New Zealand mainland; there is very little knowledge about yellow-eyed penguin populations on the sub-Antarctic islands, which are generally considered the stronghold of the species. Five of our six penguin species are in decline. There is very little published literature for most New Zealand penguins, which means that the reasons for those population declines remain unknown. Consequently, current conservation actions principally revolve around occasional population counts and ad hoc research or conservation actions that may or may not address the real threats. With ever increasing pressure from anthropogenic factors, be it climate change, pollution, or fisheries interactions our penguins are in trouble. In order to prevent or 2 Mattern & Wilson – New Zealand penguins: current knowledge and research priorities reverse their population declines and to put in place evidence-based management, we first need to identify the actual rather than the perceived threats. For this research is essential. In this report, we collate the information available on all six New Zealand penguin species. This includes published accounts (scientific papers, reports), grey literature (unpublished reports and data sets), and personal observations made by researchers that have worked with New Zealand penguins. Based on our findings, we compile a list of research priorities that should aid closing many of the knowledge gaps that prevent effective evidence-based conservation management. In New Zealand, conservation management is too often of reactive rather than proactive. Hence, penguin populations often only become the focus of management when declines are well advanced. Here, we follow the goals of the International Union for the Conservation of Nature which strives “to conserve the integrity and diversity of nature” (IUCN mission statement). In our opinion, this can only be achieved through a holistic approach where management actions are based on evidence-based strategies which necessitates at least a basic understanding of the species biology. Penguins are considered ideal sentinels for the marine environment in that their population dynamics generally reflect the state of the ocean habitat they inhabit. However, this sentinel function can only be utilized if we have at least a basic understanding of their biology and population trends. With one third of the world’s penguin populations living and breeding in New Zealand, utilizing this sentinel potential can be of international relevance in that it can highlight the effects of climate change on an important sector of the Southern Hemisphere. This report should be used in conjunction with Mattern & Wilson (2018) which lists conservation actions required for the immediate management of all six New Zealand Penguin species. Research priorities identified here in are categorised into high, medium and low as indicated by prefixes H, M, and L, and are ordered by their level of priority. References Mattern T, Wilson KJ. 2018. Research and Conservation needs and priorities for New Zealand penguins. Report to the T-Gear Charitable Trust. Nelson, New Zealand. 3 Mattern & Wilson – New Zealand penguins: current knowledge and research priorities Yellow-eyed penguin / hoiho (Megadyptes antipodes) Thomas Mattern and Kerry-Jayne Wilson Summary The yellow-eyed penguin / hoiho (Megadyptes antipodes) is endemic to New Zealand. It occurs along the south-eastern coastline of the South Island, on Stewart Island and its outliers, as well as the sub-Antarctic Auckland and Campbell Islands. The species is now the world’s second-rarest penguin species with an estimated 1,700 breeding pairs across its entire distributional range. The species is listed as ‘endangered’ by the IUCN red list and is considered ‘nationally endangered’ by the New Zealand Department of Conservation’s threat ranking system. The yellow-eyed penguin is one of the best-studied species in New Zealand with the first comprehensive population study conducted as early as the 1930s and a string of research projects that investigated various aspects of the species biology since the 1980s. Most of this research occurred on the New Zealand mainland, with very little information from the sub- Antarctic populations. A phylogenetic study found that there is very little gene flow between the mainland and sub-Antarctic populations, or between the two sub-Antarctic islands, so that the three subpopulations must be considered separate management units. The species’ mainland population has been undergoing a steady and significant decline since the mid-1990s, a trend that appears to continue; population projections predict local extinction on the mainland by 2060. While the sub-Antarctic islands are often considered to be the species’ stronghold, because they were home to a large proportion of the population in the late 1980s and early 1990s, there is no recent data to show if this is still true. Climate change has been identified to be an important factor contributing to the yellow-eyed penguin decline on the mainland, and might have caused a shift in the penguins’ prey from smaller fish (e.g. larval red cod, Pseudophycis bachus) consumed in the 1980s to large prey items (mainly juvenile and adult blue cod, Parapercis colias) since the 1990s. This may have consequences for reproductive success, with larger prey items unsuitable food for chicks, leading to starvation and facilitating disease outbreaks. However, climate change alone does not explain the population decline and it is suspected that fisheries interactions, pollution and human disturbance have all contributed to the species’ dire status. On the mainland, yellow-eyed penguins are predominantly benthic foragers that principally pursue demersal fish species. This makes them vulnerable to accidental bycatch in set nets with poor foraging on seafloor habitats degraded by bottom fishing activities such as 4 Mattern & Wilson – New Zealand penguins: current knowledge and research priorities dredging and bottom trawls. Adult survival appears to be too low to sustain the population and may have led to an imbalance between the sexes with male penguins now outnumbering females. In recent decades, disease outbreaks have affected reproductive success, and several die-off events have reduced the breeding population further. Previous reviews of Yellow-eyed penguin biology and priority lists The first major review of the yellow-eyed penguins’ breeding biology was compiled by Lance Richdale who studied the species between 1936 and 1954 (Richdale, 1949, 1951, 1957). A comprehensive review was later compiled by John Darby (Marchant & Higgins, 1990a). Research and conservation priorities were listed by Taylor (2000). He proposed that habitat protection and restoration, and introduced predator control should be of highest priority, followed by advocacy to mitigate fisheries impacts, better control of dogs, and establishment