A STATE government plan to build a 20-hectare fish farm near a popular north coast holiday town could increase shark activity and pollute the pristine marine park, critics say.
The trial, the first of its kind in NSW, will test the viability of offshore fish farming and could lead to similar projects along the coast.
The Department of Primary Industries wants to erect up to eight floating sea cages in a 500metre stretch of water at Providence Bay, near Hawks Nest. The cages, up to 40metres in diameter, would be anchored to the seabed four kilometres from shore.
The five-year project, to which the government will contribute $1.4million, will extend nearby hatchery research, trial new fish production techniques and monitor environmental effects.
The government will seek private sector funding if the project is approved.
It claims aquaculture is required to meet growing global demand for seafood. About 85 per cent of fish bought in NSW is presently imported.
The project will trial Yellowtail Kingfish and Mulloway, and could extend to snapper and tuna.
Similar systems are used in South Australia and Tasmania.
Supporters say the project will alleviate pressure on wild fish stocks, help the development of a sustainable aquaculture industry and create jobs.
But the chief executive of Dolphin Swim Australia, Andrew Parker, whose organisation operates in the proposed trial waters, says the plan will damage water quality and affect dolphins and migrating whales.
“Hectare after hectare of effluent, chemicals, possibly disease-producing caged fish in a marine park in a migratory area for whales and transitory dolphins is a very poor use of a marine park resource,” he said.
Three marine aquaculturesites are presently approved in NSW, but only one, a mussel producer near Eden, is operating.
The department says the project will potentially affect the marine habitat through changed water quality, nutrient concentrations and sediment. Chemical use, disease, impacts on migration paths and “predatory interactions”, such as shark activity, also pose a risk.
However the department does not believe the research will have a significant environmental impact, and a plan has been devised to manage environmental effects.
A department spokesman said only “disease-free fish” will be stocked in the cages and chemical use would be kept to a minimum. Hormones may be used in the hatchery but will not be used on caged fish.
A CSIRO shark expert, Barry Bruce, said aquaculture leases attract sharks but shark activity around the site is already high. The department will erect nets around the site and monitor sharks during the trial.
The aquaculture manager at Port Stephens Fisheries Institute, Ian Lyall, has previously said the project could “signal to others that may want to invest in NSW waters that there is an opportunity.”
The results of the trial will ensure future projects adhere to “best industry practice”, a spokesman said.