It isn’t every day you get to watch a fish go back to school, but that’s essentially what happened to two Maugean skates recently. After spending over two years in the comfort of a high-oxygen laboratory, these two were given their freedom back in Macquarie Harbour on the rugged west coast of Tasmania. It wasn't just a simple case of letting them go. It was a carefully planned operation to make sure they didn’t just become dinner for something else or fail to adapt to the murky reality of their home.

Back in December 2023, a team from the Institute for Marine and Antarctic Studies (IMAS) snatched these two from the harbour as an 'insurance policy.' The environment they were living in was turning into a bit of a disaster zone. The researchers wanted to make sure the species had a fighting chance if things went pear-shaped. The female of the pair proved to be a star performer, laying about 430 eggs during her time inside, which resulted in 80 healthy hatchlings. These youngsters are now the bedrock for future captive management programs.

"It's not just the eggs … the learnings that we've had from them are absolutely incredible," said Professor Jayson Semmens.

Living in a tank is a world away from the wild, and the biggest hurdle was the oxygen levels. In the lab, these skates were living the high life with 100 per cent oxygen saturation. Macquarie Harbour, however, is a bit more suffocating. The research team had to run an 'acclimation protocol.' Dr Bailee Woolley, a junior research fellow who co-led the program, explained that they slowly dialled back the oxygen in the tanks until the skates were comfortable with the harsher conditions they’d face in the wild.

Then came the 'training' phase. You’d think a fish would know how to catch its lunch, but after two years of being pampered with various snacks, their natural killer instinct had gone a bit blunt. The researchers had to play a high-stakes game of 'hunt the crab,' mixing live crabs with dead ones to kickstart their hunting habits. It’s a bit funny to think of scientists teaching a skate how to be a predator again, but they both nailed it.

The history of the Maugean skate is a bit of a grim tale. Between 2014 and 2021, their numbers plummeted by nearly 50 per cent. The main culprit is the salmon farming industry that has dominated the local waters, leading to a massive drop in the dissolved oxygen these creatures need to breathe. It’s a classic case of industry clashing with nature. In 2023, environmental groups finally forced the federal environment minister to take a good, hard look at whether those farms should even be there.

Since then, the federal government has stepped in with new legislation to lock in the future of the salmon farms, though they're also paying for a re-oxygenation program to fix the mess in the harbour. It’s a bit of a balancing act—keeping the salmon industry happy while trying to keep the last of the skates from disappearing forever. The researchers aren't just winging it, though. They're looking into the genetics of the 100-odd skates currently in captivity to figure out the best way to keep the population going.

They haven't quite decided if they want a full breeding program or just a 'head start' strategy, where they raise the young skates in safety until they're big enough to fend for themselves. Professor Semmens reckons they’ll have a clearer plan by the end of the year. For now, the focus is on the data they’ve gathered from these two pioneers. They're basically the 'guinea pigs' that have provided the blueprint for how to reintroduce captive-raised animals into the harbour without killing them in the process.

The Tasmanian Aboriginal community was involved in the release process, adding a layer of traditional oversight to the scientific endeavour. The pair of skates had spent six or seven years in the harbour before they were plucked out, so they had some 'street smarts' that the younger, captive-born skates don't have. Training those younger ones to survive in the wild will be a much tougher mountain to climb, but the team says they now have a protocol that actually works.

Key Data Points

  • The skates' wild population crashed by nearly 50 per cent between 2014 and 2021.
  • Approximately 430 eggs were produced by the single female during her two-year stay in captivity.
  • A total of 80 hatchlings were successfully bred as part of the research program.
  • The captive population now includes roughly 100 individual skates.
  • The official release of the two trial skates took place at the very end of April 2026.