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Macquarie Harbour Maugean Skate Population

Dr Rosalie Woodruff MP

Dr Rosalie Woodruff MP  -  Wednesday, 24 May 2023

Tags: Threatened Species

Dr WOODRUFF (Franklin) - Mr Speaker, I will talk today about a report that has just been released by David Moreno, scientist, and Jayson Semmens also a scientist, from IMAS. The interim report, Macquarie Harbour Maugean Skate Population Status and Monitoring, telegraphs their significant concern for the survival of the ancient Maugean skate. The summary says they have detected a potential decline in the scape population and it raises their concerns for their conservation of the species. The size of female skates has significantly increased in the 10-year period from 2012-21 and the proportion of juveniles that it has captured has significantly decreased. In normal person translation speak, that means that there are fewer breeding female fish, skates, to have babies. They simply are not there; the population is ageing and not many babies are being born.

There is evidence that there has been a substantial decline in this endangered species between 2014 and 2021 by just under a half, 47 per cent. The scale of that overall decline and the scarcity of the new baby skates that are coming into the population means they has significant concern for the conservation of the species and there is need for immediate action. Their results, they say, highlight the vulnerability of the species to degraded environmental conditions.

What are those degraded environmental conditions? I am glad you asked, Mr Speaker. What we know is that the skate are walking the short plank to extinction because of there is no oxygen in the lower harbour. IMAS themselves they have now confirmed that that has been caused by fish farm nutrient overload amongst other things, including climate change and heating waters.

The Government's treatment of the Maugean skate over the last eight years has been a parade of obscene distain for threatened species protection. They know, and it has been writ large for eight years now that the biomass, the nutrients that are being dumped into Macquarie Harbour have been killing off the oxygen levels in the waters. We have seen that through the Senate inquiry that Senator Whish-Wilson for the Australian Greens got up in 2015. It was very clear the companies at the times where fighting amongst themselves, doing their very best to increase biomass, despite the fact that all the warning levels were there from the IMAS scientists that oxygen levels had almost disappeared.

We knew in 2005 there was only 2000 tonnes of salmon that were being farmed in Macquarie Harbour. That is what sustainability looks like. But we cannot help ourselves in Tasmania. It is not good enough if you are not doubling and doubling and doubling. So, what was a sustainable aquaculture industry, and had no problems existing in Macquarie Harbour for a very long time, went on steroids under the Liberals, and the Labor Party beforehand, and it grew fourfold by 2011. By 2015 it had grown to nearly 20 000 tonnes of salmon and there were ten different fish farm leases in the harbour.

Neville Barrett, the IMAS scientist who has for so long followed the Maugean skate, predicted from the outset that the oxygen would decline straight away. That is what they found. Little oxygen in the ten metres below the harbour. Dead zones were discovered where the benthic layer was devoid of life and there was damage identified to the Tasmanian Wilderness World Heritage Area.

By 2018, 1.35 million salmon had died as a result of the lack of oxygen when there was a heatwave and a water flushing event. That is just the evidence that is sitting there that we have in front of us. People who are listening to this would wonder why the Government has not stepped in earlier. We would wonder that too if it was not for the fact that we have Henry Batista on the front page of the Mercury today calling on the Government to go in harder and to get rid of the pathetically weak environmental protection because they are 'time consuming and expensive'. So, he thinks the remnant Tasmanian environmental protections that are not even protecting the Maugean skate from going extinct in the next heatwave, which is what the scientists from IMAS have predicted.

The next heatwave, will in all likelihood be this summer, because El Niño is being very clearly predicted by the Japanese Bureau of Meteorology and it is likely under the Australian Bureau of Meteorology projections. We are going to have a heatwave. It is going to cause all of our waters to warm, and it is going to be devastating for the critically endangered Maugean skate. So why would the Government not just pull out all the salmon farms from Macquarie Harbour. What they are doing is knowingly causing that skate to go extinct. They are doing it purposefully and wilfully with full knowledge that they have had for eight years now. This latest report makes it abundantly clear that if they do not pull the salmon farms out of Macquarie Harbour, they are causing the Maugean skate to go extinct.

The sad thing is, I think they have lost their moral compass on this entirely. The Liberals do not care because they would rather have cosy corporate dinners with the Batista brothers; they would rather chat to Henry's uncle Jose Lea and to the CEO of Cooke Canada and feel important, like they are just handing it all to big business. Just like they do on short-stay accommodation. We have to get it out because we love the beautiful diversity of Tasmania. People are not going to stop wanting to protect the Maugean skate.