This record provides an overview of the NESP Marine and Coastal Hub emerging priorities study - "Application of environmental DNA to survey Bathurst Harbour Tasmania for the endangered 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 and the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999. Its known population is small (~3,000 individuals, Macquarie Harbour, 2016) and highly restricted, having only been recorded in two isolated estuaries: Bathurst Harbour and Macquarie Harbour in south-western/western Tasmania. This constitutes one of the most limited distributions of any known extant elasmobranch. Although the skate was first discovered in Bathurst Harbour, most knowledge of the species stems from the Macquarie Harbour population. Only four individuals have been reported in Bathurst Harbour, with the last reported sighting in 1992. Environmental conditions in Macquarie Harbour have changed markedly since then due to anthropogenic activities in and around the estuary including historical mining, hydro-electric generation and alteration of natural river flows, and marine fish farming. Previous research has shown clear signs of population stress and evidence of detrimental impacts of degraded environmental conditions on the Maugean Skate in Macquarie Harbour. Understanding the potential population status of the Maugean Skate in Bathurst Harbour will assist in determining conservation actions. This study used Environmental (e) DNA to determine the presence/absence of Maugean skate in Bathurst Harbour, strengthening the evidence base for effective conservation plans and specific recovery actions. Outputs • Maugean skate eDNA sampling data and inferred species distribution (presence/absence) [dataset] • Final Project Report, including a short summary of recommendations for policy makers of key findings [written]

This record provides an overview of the NESP Marine and Coastal Hub Research Plan 2023 project "Delineation and estimation of the Maugean skate population in Macquarie Harbour, Tasmania". No public data outputs are planned for this project. -------------------- The Maugean skate (Zearaja maugeana) is now only found in Macquarie Harbour on Tasmania’s west coast, which has a long history of environmental degradation. The species is listed as Endangered under Commonwealth and Tasmanian legislation, and its restricted distribution, small population size, and exposure to degraded environmental conditions make population monitoring a high conservation priority. Recent research suggests that the Macquarie Harbour population may be declining. However, existing abundance estimation methods are inadequate because the species is cryptic, capture-based methods pose risks to skate health, and conventional optical surveys are limited by the harbour’s shallow, stratified, and highly turbid conditions. This project developed and tested new approaches to estimate and monitor the Maugean skate population using next-generation genetic sequencing and novel imaging technologies. Non-invasive acoustic methods (adaptive resolution imaging sonar (ARIS), synthetic aperture sonar, performed better than optical approaches (LiDAR, conventional video), under Macquarie Harbour conditions. ARIS was identified as the most suitable image-based monitoring tool for future population surveys. The genetic component generated the first reference-quality whole and mitochondrial genomes for the species and sequenced samples from 162 individuals. Genome-wide single nucleotide polymorphism (SNP) analyses showed that the Macquarie Harbour population has very low genetic diversity, which may influence how genetic risks are interpreted in recovery planning. The project produced new monitoring methodologies, genomic reference resources, and population genetic datasets to support future monitoring of Maugean skate abundance, population structure, and genetic health. The findings will inform conservation planning and evaluation of recovery strategies including captive breeding, translocation, and long-term genetic monitoring under changing environmental conditions. Outputs • Tissue sampling results and genome-wide population genetic structure [dataset] • Final project report [written]

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]

The Maugean Skate Zearaja maugeana is a micro-endemic species known from only two isolated estuaries, Bathurst and Macquarie Harbours in southwestern/western Tasmania. This constitutes one of the most limited distributions of any known extant elasmobranch. As a result, the species is listed as ‘Endangered’ under the Threatened Species Protection Act (Tasmania) and the Environmental Protection and Biodiversity Conservation Act (Commonwealth). Even though it was first discovered in Bathurst Harbour, most of what is known about the species comes from the Macquarie Harbour population. Only four individuals have ever been reported in Bathurst Harbour, with the last known sighting occurring in 1992. This study used environmental DNA (eDNA) to determine the presence/absence of the Maugean skate in Bathurst Harbour on the southwest coast of Tasmania. Water samples were collected from the seafloor in Bathurst Harbour in November 2021 and February 2022, and in Macquarie Harbour (control samples) in December 2021. Samples were filtered using a self-preserving eDNA sampling system. Following each survey DNA from the samples was extracted and analysed through qPCR amplification. Mitochondrial primer pairs from two gene regions were used to detect the presence of Maugean skate DNA in the samples. Where possible, positive detections were sequenced, and their identity verified.