As a species listed under CITES Appendix II, SHH are harvested under a total allowable catch of 200t, which was implemented for Australia to meet its obligations under non-detriment findings. Further, the conservation status of SHH is currently being reassessed under the EPBC Act. A recent SHH stock assessment undertaken using data poor methods highlighted the paucity of data available for the species and, importantly, that informative data will almost certainly not be available in the foreseeable future. Therefore there is no expecation that current uncertainty will resolve with status-quo data collection strategies.

New approaches, such as CKMR, are required to gather informative data to better understand stock status and verify that the 200t catch limit is appropriate. The project proposed here aims to explore likely scenarios to determine the sample size, budget, and required sampling logistics in order to obtain either an estimate of spawning abundance of SHH stocks found in northern Australia, or to determine that the current catch limits will not be detrimental to the sustainability of the species. This project intends to utilise available fisheries observer data and the current understanding of population trends and demographic information to evaluate

(1) whether the species is a viable candidate for close-kin mark-recapture assessments, and

(2) the extent of sampling required to produce a precise estimate of population abundance and/or other population metrics useful for management.