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Maugean skate’s only home is Macquarie Harbour, which hosts intense salmon farming
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Tasmania’s Maugean skate may go the way of the Tasmanian tiger within 10 years and is only one extreme weather event away from extinction
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Removing salmon pens would give Maugean skate a fighting chance of survival
The Australian Marine Conservation Society (AMCS) and Humane Society International (HSI) Australia welcome federal Environment Minister Tanya Plibersek’s announcement today of $2.1 million funding to establish a captive breeding program for Tasmania’s endangered Maugean skate, and say a clean harbour is also needed.
AMCS shark scientist Dr Leonardo Guida said: “For a captive breeding program to have the best chance of success, the endangered Maugean skate needs a healthy home.
“The Maugean skate’s only home is Macquarie Harbour, where intensive salmon farming is depleting what little oxygen there is, and manipulated river flows to generate electricity are limiting oxygen-rich seawater from entering the harbour.
“The Australian Government knows what has to be done to improve the water quality of Macquarie Harbour. Removing salmon pens would give the Maugean skate a fighting chance of survival, as well as addressing the freshwater flows from the hydro-electric dams.”
The Threatened Species Scientific Committee have told the federal government in advice published yesterday: “There is a significant correlation between the reduction in dissolved oxygen levels and increases in salmonid aquaculture due to the bacterial degradation of organic material introduced into the water column from fish-feed and fish-waste.”
HSI Head of Campaigns, Nicola Beynon, said: “The funding for a Maugean skate breeding program is welcome as an emergency measure in a recovery process that must also include cleaning up Macquarie Harbour. This is an extinction emergency. The Maugean skate should be listed as ‘Critically Endangered’ giving it the strongest possible protection under the Environment Protection and Biodiversity Conservation Act. The federal environment minister must use all of her significant powers under the Act to save it.
“Federal Environment Minister Tanya Plibersek needs a ‘no regrets’ approach if the government wants to ensure its aim of no new extinction under its watch.”
The Maugean skate – part of the cartilaginous group of fishes that includes sharks and rays – lives solely in Macquarie Harbour on the remote west coast of Tasmania. The water quality in Macquarie Harbour, with its narrow, shallow entrance, is extremely poor, primarily because the water is depleted of oxygen from intensive salmon farming as well as manipulated river flows into the harbour that prioritise hydro electricity generation. The skates and any eggs they lay are deprived of the oxygen they need to live.
A recent study showed the skate’s numbers have plummeted recently, and scientists fear it could become extinct within 10 years or wiped out in another extreme weather event. After intense coastal storms in 2019, the population was cut in half to about 1500 individuals.
Urgent recovery measures are needed before the end of this year, including restoring the health of Macquarie Harbour, implementing a captive breeding program and ongoing monitoring of the population. In February this year, AMCS and HSI Australia nominated the Maugean skate for Critically Endangered status under Australia’s nature laws.
