Newly hatched Maugean skates
Groundbreaking conservation efforts have saved one of the world’s most endangered marine species, the Maugean skate, from impending extinction. Researchers successfully captured wild specimens and facilitated their reproduction in a controlled environment, marking a significant milestone in marine conservation.
The Maugean skate (Zearaja maugeana) is endemic to Macquarie Harbour on Tasmania’s rugged south-west coast. This region is characterized by naturally low oxygen levels, which already challenge fish survival. However, human activities, particularly salmon farming and alterations in river flow due to hydroelectric projects, have exacerbated these difficulties.
Estimates suggest that the Maugean skate population has dramatically decreased, dropping by half between 2014 and 2021. Current estimates indicate there are just over 1,000 individuals remaining, with a troubling predominance of adults and insufficient juveniles reaching maturity.
In response to a marine heatwave affecting the region last year, researchers undertook a dramatic intervention to protect the species from extinction. In December 2023, the team harvested 50 eggs, successfully hatching over half of them in captivity. Additionally, four adult skates were collected, although two did not survive. The two remaining females were kept apart, leading to an unexpected outcome when one laid eggs.
The research team noted that skates possess the ability to store sperm, allowing for delayed fertilization. “She’s been laying on average every four days, two eggs each time,” a researcher stated. “We currently have over a hundred eggs, and most appear to be viable.”
To enhance genetic diversity among the captive-bred juveniles, the team is exploring options to capture additional females that have already been inseminated, ensuring their return to the wild post-egg collection.
However, experts warn that captive breeding alone is not sufficient. Efforts are concurrently underway to address environmental challenges in Macquarie Harbour, including experiments in oxygenation of the water.
There are no immediate solutions; even with successful breeding, it will take four to five years for these skates to mature and potentially contribute to the population. The stakes are incredibly high; failure to revive this species would represent the first extinction of a ray or shark species in modern history, marking a critical moment in marine conservation efforts.
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