Petuna set to test Tassal waste tech

PETUNA Aquaculture has announced plans to trial Tassal’s waste capture system on its own Macquarie Harbour pens in a move that has been criticised by Tasmania’s other major salmon producer.

Petuna yesterday announced it is in discussions with Tassal to trial the technology on four pens from January, subject to approval from the Environment Protection Authority.

Tassal was required to develop the system earlier this year to mitigate the impact of up to 4000 tonnes of salmon it is farming above the harbourwide 12,000-tonne cap.

However, Petuna said it had no intention of farming additional fish over the biomass cap.

Petuna acting chief executive David Wood said Petuna was in the final stages of negotiating a commercial arrangement with Tassal to trial the system.

“This is an exciting industry innovation, which has so far exceeded expectations, proving a vital tool in supporting sustainable farming in the harbour into the future,” Mr Wood said.

Huon Aquaculture executive director Frances Bender said waste capture did nothing to address the primary environmental concern in Mac- quarie Harbour — the decline in dissolved oxygen levels.

Ms Bender said waste capture might mitigate the impacts of salmon waste on the harbour floor, but should not be seen as a measure to achieve compliance and justify “unacceptably high” levels of salmon biomass, which could lead to depleted oxygen.

“It appears that Petuna is looking to join Tassal in managing compliance without looking after the environment,” Ms Bender said.

“Petuna may manage to install waste capture but, given the current environmental conditions, it’s like saying “the operation was a complete success but the patient still died.”

Environment Tasmania strategy director Laura Kelly said she was concerned that Tassal and the EPA had not yet released reports or detailed data on the impact of the waste capture system.

Ms Kelly said the system should be reviewed under the Commonwealth Environment Protection and Biodiversity Conservation Act.

Petuna plans to dispose of treated wastewater collected from beneath pens in Devonport as part of the agreement recently reached between Tassal and TasWater.

The Tasmanian Greens on Monday welcomed Tassal’s decision not pump the waste water into the harbour, as had previously been suggested, but said it remained concerned about the company’s new disposal plan.