Hon John Key
PO Box 18888 Parliament Buildings
Wellington, New Zealand
New Zealand can act to conserve the New Zealand sea lion
Dear Prime Minister:
The purpose of this letter is to convey the grave concern held by the Board of the Society for Marine Mammalogy about the future of the New Zealand sea lion, a species whose production of young has declined over 30% in the past decade, and to ask you to initiate urgent actions to prevent its further decline. The New Zealand sea lion may not be at risk of near term extinction, but its population decline is sufficiently serious to warrant a precautionary approach to fisheries management actions and a review of research priorities.
The Society for Marine Mammalogy is the largest professional group in the world dedicated to the study of marine mammals and consists of approximately 2,000 scientists from 60 countries. The Society’s goal is to facilitate the understanding and conservation of marine mammals and their ecosystems. We appreciate the global leadership that New Zealand has played in the conservation of marine ecosystems including the conservation of marine mammals.
New Zealand sea lion was relisted on the IUCN Red List of Threatened Species in 2008 as ‘Vulnerable’, because expert opinion suggested that their population was likely to decline by more than 30% over the next three generations as a result of the marked decline in pup production in the last 10 years at the major breeding areas. The IUCN was so concerned about the species that it recommended that the species be reviewed again within a decade. We understand that during the 2008/2009 breeding season, there was a further 31% drop in pup production relative to the previous season at the Auckland Islands, their main breeding area and that the New Zealand sea lion could be relisted under the New Zealand threatened classification listing in 2009 as Nationally Critically Endangered.
The reason for the decline is not clear, but is likely to be attributable to a number of factors. I understand that the most influential of these factors may be the on-going fisheries by-catch of adult females and a series of bacterial disease outbreaks. The species’ range is reduced from historic levels; they are now limited to the sub-Antarctic Islands whereas midden records indicate they used to be widespread.
Although the role of local trawling fisheries in the decline of the New Zealand sea lion population is debated, the continued annual removal of animals through bycatch may well reduce the resilience of a vulnerable and declining population. We understand that The Ministry of Fisheries increased the allowed sea lion by-catch take from 81 last year to 113 this year. On the basis of the continuing population decline of the species, we urge you to adopt a more precautionary approach to setting an allowed level of bycatch for the species. One robust approach would be to use the Potential Biological Removal method to estimate a total level of allowed annual fishery bycatch for the species. The Potential Biological Removal method is the process used in the US to set bycatch levels (PBR; Wade and Angliss 1997). Alternatively, we suggest that a peer-reviewed population viability analysis be used to evaluate any change in allowed bycatch. Ultimately, a comprehensive review of management and research options beyond 2010 would, in our view, provide a useful approach to ensuring a continuation of your best practice to marine conservation issues.
The New Zealand sea lion is the only seal or sea lion that is restricted to New Zealand. It clearly is of high social value; both the Otago Peninsula and New Zealand’s sub-Antarctic Islands, New Zealand sea lions are an increasing focus of the burgeoning tourist industry.
The future of the New Zealand sea lion is clearly reliant on New Zealand’s management decisions and actions. We hope that New Zealand’s handling of the New Zealand sea lion decline will continue to set a global standard for the effective conservation of the world’s marine mammals.
Please contact me if you would like further independent scientific advice from members of the Society who are experts in the conservation of sea lions.
Andrew J. Read
President of the Society of Marine Mammalogy
Rachel Carson Associate Professor of Marine Conservation Biology
Division of Marine Science and Conservation
Nicholas School of the Environment
Phone: + 1 -252-504-7590
Hon Tim Groser Minister of Conservation, Parliament Buildings, P.O. Box 18888 Wellington
Hon Phil Heatley, Minister of Fisheries, Parliament Buildings, P.O. Box 18888 Wellington