Salmon industry tinkering with toys in Macquarie Harbour

Salmon Tasmania said (Friday 29 September 2023) it had teamed with Australian Government's Fisheries Research and Development Corporation (FRDC) and the Institute for Marine and Antarctic Studies (IMAS) to place a barge on the harbour to manufacture an increased level of oxygen to help save the endangered Maugean skate.

The $6m, two-year project will start this summer for a first trial as part of a long term strategy yet to be revealed. A research team will draw water from the sea at depth from a barge on Macquarie Harbour and inject highly concentrated micro and nano bubbles of oxygen into the drawn water, and then release it back into deeper water sections.

Salmon Tasmania chief executive Luke Martin said "At a minimum, we aim to offset the total oxygen drawdown of our own salmon aquaculture activities in the harbour, and further reduce the impact of our operations on the environment."

But the Bob Brown Foundation said the investment did not mitigate or undo the damage caused by aquaculture.

"The only reason we're in this situation in the beginning is because of how much they've abused fish farming in Macquarie Harbour," Antarctic and marine campaigner Alistair Allan said. "The oxygen level collapsed in 2017 because of fish farming … so you take all the oxygen away in the initial event, and then you want to try and come back, they need to get out and give time for the ecosystem to recover."

"We can't be in there tinkering with toys and left with left-of-field ideas about mechanical engineering for a harbour that's six times bigger than Sydney Harbour," he said.

A NOFF spokesperson questioned the energy required, and added that enriching oxygen levels would benefit the industry by enabling salmon to better withstand increasing water temperatures, so the proposal is far from magnanimous.