Developing novel remote camera approaches to assess and monitor the population status of Australian sea lions
The Australian sea lion (Neophoca cinerea) is the only endemic species of Australian pinniped and is listed as Vulnerable under the EPBC Act due to historical reduction in numbers, declining population trends, limited biological productivity and continued bycatch in various fisheries. Measures to mitigate sea lion mortality in the Commonwealth's Southern and Eastern Scalefish and Shark Fishery include extensive gillnet fishing closures that have led to significant displacement of fishing effort. Despite the measures to protect South Australian sea lion colonies, pup production has been estimated to have declined at most South Australian colonies and overall by 2.9% per year or 4.4% per breeding cycle between 2004-2008 and 2014-2015 (Goldsworthy et al., 2015).
Gillnet exclusion areas have also been proposed in the Western Australian Demersal Gillnet and Demersal Longline Fisheries, however these have not yet been implemented, in part due to uncertainties in the current status of most Western Australian sea lion colonies and risk of unintended consequences from displaced fishing effort. Despite the high level of conservation concern for this species and the severity of fishery management measures aimed at reducing their bycatch mortality, abundance has not been estimated for most WA colonies since the early-1990s (Gales 1993). Contemporary assessments of colony status are therefore required to identify the WA colonies that are most at risk from depletion (either through fisheries bycatch or other natural or anthropogenic processes) and guide effective conservation decisions.
Historically, monitoring has involved a 'boots-on-the-ground' approach to count the numbers of pups being born. However, this approach is expensive, logistically difficult, hazardous and entirely dependent on accurate estimation of the timing of colony-specific pupping seasons. It is therefore proposed to evaluate the feasibility and cost-effectiveness of remote camera methods to collect alternative sea lion abundance estimates.
