Good news for endangered skate as survey shows numbers on the rise

An increase in the number of juvenile Maugean skates is a hopeful sign for the survival of the endangered species, scientists say.

Baby Maugean Skate. Picture: Adam Gibson

An increase in the number of juvenile Maugean skates is a hopeful sign for the survival of the endangered species, scientists say.

Research by the University of Tasmania’s Institute for Marine and Antarctic Studies has shown an increased presence of young Maugean skates for the first time in a decade.

Nine days of fishing in Macquarie Harbour have caught 38 skates so far in 2024.

IMAS Maugean skate captive breeding program leader Professor Jayson Semmens said data collected since 2021 suggests the population may be stabilising.

“Although the population remains significantly lower than historical levels, catch per unit effort data — a standard measure of relative abundance — shows the skate population has stabilised since 2021 and there has been no overall further decline,” he said.

“It takes approximately six years for Maugean skate hatchlings to reach maturity, so while immediate recovery of adult biomass is not expected, the presence of juveniles at a similar proportion relative to adults in the sampling as we were seeing in 2014 is a positive sign. “Continued monitoring will be crucial to understanding the long-term trajectory of the species.”

Maugean skate

IMAS researcher Dr David Moreno said it was too early to predict long-term outcomes.

“Updated population models and action plans are needed to ensure the species’ survival in Macquarie Harbour, its last remaining habitat,” he said.

Minister for Parks and Environment Nick Duigan expressed no such uncertainty.

“It’s clear that the latest IMAS report rebuts previous predictions of catastrophic skate population decline, and complements recent Environment Protection Authority data revealing oxygen levels in the harbour are also at their highest in a decade,” he said.

“The future is bright for the skate, not only because of this latest promising population study but also the success of our skate captive breeding program at the IMAS labs at Taroona.”

The 2024-25 Budget provides $8m over the next four years to establish a Tasmanian Threatened Species Fund which will directly support conservation activities for priority species, including the Maugean skate.

Australian Marine Conservation Society Fisheries and Threatened Species Campaign Manager Alexia Wellebelove said the skate wasn’t out of the woods yet.

“There are still only an estimated 40 to 120 mature skates left in the harbour and its extinction could be in as little as 10 years’ time, possibly earlier if a big storm creates another upturning event like the one that decimated the population in 2019,” she said.

“Salmon farming has dramatically depleted the oxygen levels in Macquarie Harbour, and removing salmon farming is the fastest way to improve oxygen levels for the skate to survive and recover.”

Salmon Tasmania CEO Luke Martin said the research confirmed it would be unreasonable of the Federal Environment Minister Tanya Plibersek to consider shutting down salmon aquaculture in Macquarie Harbour.

Salmon Tasmania CEO Luke Martin. Picture: Linda Higginson

“As an industry, we have never shied away from concerns about the Maugean skate, and indeed we have invested heavily in the scientific research and analysis that is now shaping the conservation response to ensure the future of the species in Macquarie Harbour,” he said.

“We have also consistently said we expect all regulatory decisions made about our industry’s presence in the harbour to be based on science and not political agendas or in response to pressure from single-minded activist groups.”