Macquarie Harbour’s critically endangered Maugean skate is edging back from the brink, yet the Tasmanian Environment Protection Authority (EPA) has not published a single dissolved-oxygen (DO) profile for 2025, a lapse that makes it impossible to judge whether the species’ fragile recovery is continuing or stalling.

Long-term gill-net monitoring shows the skate population crashed after 2014 when bottom-water oxygen plummeted, but a recent lift in oxygen has brought the first wave of juveniles in a decade. Yet uncertainty means as little as 1,600 animals may still be alive, a perilously small number for a species confined to one estuary.

“Transparent oxygen data underpin every management decision, from salmon-farm feed limits to emergency contingency planning,” said Matt Testoni, Save the Skate campaigner at Environment Tasmania, who advocates for the species for an upcoming film tour. “When significant numbers of adult skates died during the 2019 hypoxia events, the EPA promised quarterly disclosure. We are now seven months into 2025 and the public record is blank.”

Without fresh DO readings, researchers cannot update the Population Viability Analysis, and stakeholders including the state’s aquaculture sector lack the early-warning system needed to head off another oxygen crisis.

Mr Testoni is urging the EPA to release all 2025 DO data immediately, reinstate the agreed quarterly publication schedule (including raw sensor downloads), and convene an independent technical review to confirm that current monitoring density is adequate for early warning.

“The Maugean skate has shown it can rebound when oxygen improves, but with a minimum plausible population of just 1 600 animals, we have zero margin for complacency,” Mr Testoni said. “Timely, transparent reporting is the simplest safeguard the EPA can deliver today.”