Population viability analysis of New Zealand sea lions, Auckland Islands, New Zealand’s sub-Antarctics: assessing relative impacts and uncertainty

摘要: A common issue faced in wildlife management is how to assess the uncertainty of potential impacts on viability a species or population. The pup production New Zealand (NZ) sea lions (Phocarctos hookeri) has declined 50% last 12 years at their main breeding area, Auckland Islands. two major known atypical NZ are as follows: (1) direct mortality bycatch trawling and (2) bacterial epizootics, which can affect reproduction mortality. Both these include high levels uncertainty, with fisheries data being variable due percentage observer coverage effect lion exclusion devises, while timing severity epizootics not predictable. In this paper, an age-structured model population Islands was built examine predicted effects catastrophes (bacterial epizootics), both separately then combined, over 100-year period using VORTEX analysis programme. These models compared against 15 years empirical field determine actual level observed. Model results indicate that although naturally occurring reduce growth rate population, it does cause decline Island However, sustained current estimated levels, particularly considering its impact adult female survival, could result possible functional extinction modelled time period.