- Two Maugean skates collected from Macquarie Harbour in 2023 for captive rearing program have been returned to their natural habitat
- The skates leave behind a controlled environment to return to a harbour with dangerously low oxygen levels due to government inaction
- Captive rearing program continues despite ongoing environmental damage caused by salmon farming in Macquarie Harbour.
Two adult Maugean skates - male and female - have been returned to Macquarie Harbour, marking a bittersweet milestone in efforts to save this endangered species from extinction, the Australian Marine Conservation Society said today.
After more than two years in captivity, these skates deserved to be returned to their home. Traditional Owners have a deep connection to these waters and the skates that have inhabited them for millennia, and the skates' return to Country holds cultural significance for them.
In December 2023, four adult skates were collected from Macquarie Harbour by scientists from University of Tasmania's Institute for Marine and Antarctic Studies (IMAS). Two died shortly after, but the adult female laid 400 eggs from the stored sperm of five different males in the wild, with 79 hatchinglings surviving in captivity to date. No breeding in captivity has been confirmed. The captive rearing program has since generated invaluable scientific knowledge about Maugean skate biology, behaviour, and husbandry that will prove essential for ongoing conservation efforts.
The captive rearing program was initiated as an emergency response to the ongoing imminent extinction risk for the skate - first publicly raised by AMCS together with IMAS scientists - and supported by the Tasmanian and Federal governments. The primary driver of extinction continues to be dangerously low dissolved oxygen levels caused by intensive salmon aquaculture.
Since then, the Federal Government has continued to ignore scientific advice from its own department that salmon should be removed from Macquarie Harbour to help the Maugean skate's survival, instead ramming through legislation to override the country's national environmental laws and allow salmon farming to continue there.
AMCS shark scientist Dr Leonardo Guida, said: "There is deep appreciation for the scientists who continue to work incredibly hard to look after the skates, and ensure every bit of knowledge gained can best inform species conservation moving forward.
"After more than two years in captivity, these skates deserved to be returned home to Macquarie Harbour, but Australians need to know these skates are leaving what was effectively a long-term spa retreat with oxygen-rich seawater to return to a significantly deteriorated harbour.
"A successful captive rearing program is one you no longer need, but for that we need a healthy harbour and, for that to happen, salmon farming must cease in Macquarie Harbour.
"How these adult skates cope going back into the harbour will greatly inform how a captive rearing program can best plan to return individuals to the wild and bolster the population, which must surely be the ultimate aim."
In Macquarie Harbour, the Maugean skate population is predominantly adults with most remaining females nearing the end of their natural lives (10-12 years), much like the female returned. While some juveniles have been detected, there are serious concerns they could be struggling to reach reproductive age (4-6 years) in these degraded conditions, causing the Maugean skate to age out of existence.
Dr Guida said: "This species can still be saved, but only if we match scientific effort with political courage. Federal Environment Minister Murray Watt can immediately list Macquarie Harbour as critical habitat under our national nature laws, but if political will fails to remove salmon from the harbour, then consumers can discourage farming of Atlantic salmon in Macquarie Harbour by choosing not to buy it.
"The clock isn't just ticking for the Maugean skate; it's running out."
