NESP MaC Project 4.25 - Modelling adult abundance and habitat distribution of Maugean skate (CSIRO)

This record provides an overview of the NESP Marine and Coastal Hub Research Plan 2024 Emerging Priorities project "Modelling adult abundance and habitat distribution of Maugean skate". For specific data outputs from this project, please see child records associated with this metadata. -------------------- The Maugean skate (Zearaja maugeana) is listed as Endangered under Tasmania’s Threatened Species Protection Act 1995 and the Commonwealth Environment Protection and Biodiversity Conservation Act 1999. The species has one of the most restricted distributions of any extant elasmobranch, having only been recorded in Macquarie Harbour and Bathurst Harbour in western Tasmania. The Macquarie Harbour population is small (~3,000 individuals) and exposed to ongoing environmental pressures, making robust population assessment and habitat monitoring a high conservation priority. This project investigated Close Kin Mark Recapture (CKMR) as a priority method for estimating historical abundance and supporting long-term monitoring of Maugean skate in Macquarie Harbour, as identified in the species’ Roadmap of Agreed Actions and 2023 Conservation Advice. CKMR uses next-generation sequencing to identify close relatives among sampled individuals and model breeding population size, adult survival and population trends. A second project component modelled the distribution of critical Maugean skate habitat in relation to dissolved oxygen, temperature and depth. Telemetry data from tagged skates were combined with biophysical harbour models and habitat selection modelling to generate potential habitat maps for a 2017-18 hindcast period and forecast scenarios based on recent and evolving water-quality conditions. These maps were assessed against existing knowledge of skate habitat to identify critical areas within Macquarie Harbour and inform future spatial and temporal sampling strategies. Project outputs include independent population-assessment methods and hindcast/forecast habitat suitability maps for Macquarie Harbour. These outputs support conservation decision-making, evaluation of remediation scenarios, identification of critical habitat areas, and future monitoring and sampling design. Outputs • High-quality DNA sequences of Maugean skate [sequencing data] • Hindcast maps (2017-18) of potential Maugean skate occupation [spatial data] • Recent and forecast (evolving) maps of potential Maugean skate occupation under different management scenarios [spatial data] • Estimates of spawning stock abundance of the Maugean skate from CKMR analysis [data contained in written report] • Final project report [written]