Development and implementation of a population estimation protocol to provide an estimate of East Coast population numbers for grey nurse sharks (Carcharias taurus)
Department of Sustainability, Environment, Water, Population and Communities, 2010
- Development and implementation of a population estimation protocol to provide an estimate of East Coast population numbers for grey nurse sharks (Carcharias taurus) (PDF - 4359 KB)
About the document
The east coast population of the grey nurse shark (Carcharias taurus) is listed as critically endangered under the Environment Protection and Biodiversity Conservation Act 1999. Due to limited long-term information available on the grey nurse shark and a need to assess how its population may change over time, the Department commissioned Cardno Ecology Lab to develop and implement a population estimation protocol and to undertake a study to provide estimated east coast population numbers for grey nurse sharks.
A technical workshop on the preferred protocol for the study took place at the Sydney Institute of Marine Science, Chowder Bay, Sydney on 11 July 2008. Representatives of the various stakeholder groups linked to the study attended the workshop at which the proposed methods of the study were presented. The protocol agreed at the workshop was based on mark-recapture procedures using Photo-identification evaluated by photographing the left flank of as many sharks as possible during two surveys. The geographical extent of the surveys spanned the range of previous surveys of grey nurse sharks, but included 22 additional sites identified by local divers and fishers that had not previously been surveyed.
The population was estimated to be 1365 individual grey nurse sharks, with 95% confidence that the population estimate is between 1146 and 1662 individual grey nurse sharks.