Today’s release of the IMAS population report for the Endangered Maugean skate points to a population on a cliff’s edge.
The report indicates that numbers in the skate population is moving into the Tasmanian Wilderness World Heritage Area, and numbers in the areas shared with salmon farms are down.
In short, the report indicates a population in decline. From the report’s summary “these patterns cannot be attributed solely to population growth in the World Heritage Area alone, and therefore, likely reflect some redistribution of adult individuals among sites.”
Key information
● “A number of small juveniles were caught in 2022, with some individuals from that cohort also caught in 2023 and 2024, indicating that at least one significant recruitment event may have occurred since the monitoring program re-started in 2021. Despite the size composition data suggesting eight years of little to no recruitment between 2014 and 2021” - p6
● Conditions are still not ideal in the TWWHA (recent EPA report shows dissolved oxygen in the red) ● In order to hatch, eggs need healthy levels of oxygen consistently over 7 months, where they are being laid.
● Adults on the other hand CAN handle short periods of low oxygen - and are leaving the areas of the harbour where salmon farming operates.
● The population is reaching a critical cliff - with more adults than juveniles, and without rehabilitation of the TWWHA this is dangerous for a population in decline.
Jess Coughlan, Senior skate campaigner at Environment Tasmania says:
“It appears from this report, that the skate is in decline and seeking habitat away from salmon farms. Skate populations are relocating to the TWWHA but this doesn't necessarily mean safety for the species - dangerously low oxygen levels persist in the Heritage Area.”
“Again, after nearly 3 years of scientific advice to reduce or remove salmon biomass from the harbour, we haven’t seen the kind of improvements that the level of public spending should be yielding. This report demonstrates that failure to adequately remediate Macquarie Harbour is still casting a long shadow over the future of this species.”
“As the population of the endangered Maugean skate edges closer to the cliff, we can’t know for sure that its survival is protected for even the next decade - or has the resilience to withstand the upcoming El Nino event. Without annual and thriving recruitment, each year that passes, the species is on a knife-edge.”
All comments attributed to Jess Coughlan Senior Campaigner Environment Tasmania [email protected] 0431684741