Environmentalists and the river abalone industry want expansion of the Tasmanian salmon industry stopped.
The groups say underwater vision taken around salmon farms, and a report by a marine scientist provided exclusively to the ABC's 7.30 program, show damage is being done to Tasmania's waterways, ABC News reports.
Head of sustainability at Tassal, the largest producer of salmon in Tasmania, Linda Sams said the company needs to expand to keep up with demand.
“We're looking to grow in a sustained kind of responsible way,” Sams said.
“By 2030 we talk about doubling our production, but there's a number of ways we'll do that.
“We'll do that through actually growing more fish, but we'll actually do that as well by growing fish more efficiently.”
Meanwhile, underwater footage filmed around several locations, including Hope Island, which is close to Tassal salmon farms, allegedly shows pollution from the cages.
Environment Tasmania's Rebecca Hubbard said the water was contaminated by faeces and uneaten feed falling from the cages.
“There is a big difference in the water clarity and there is dust that's kind of settling all over the rocks and the kelp,” she said.
“One of the big concerns that people have is this dust and pollution impacting on the marine life and the fish.
“The industry has expanded hugely in the last 20 years and unfortunately now that means that they are polluting and damaging Tasmanian waters.”
Chief executive of the Tasmanian Abalone Council Dean Lisson said the footage supported what divers had been seeing.
“The footage is showing quite clearly a layer of sediment in and around Hope Island which is just adjacent to Tassal's main operations, so the evidence is there as far as we're concerned,” Lisson said.
“The water is more milky, there's obviously more sediment in the water and in conjunction with that we've seen a reduction in the amount of abalone we've been able to harvest.”
Sams denied Tassal was polluting the waterways, and said a three-year study by the University of Tasmania showed Tassal was just one of many factors influencing the waterway.
But a new scientific report commissioned by Environment Tasmania found gaps in environmental monitoring.
“Reefs and kelp forests, which are critical habitats to hundreds of species including commercially significant rock lobster, abalone and other fish, are not actually being monitored,” Hubbarb said.
Dr Hugh Kirkman, who conducted the report, recommended urgent research be conducted to measure the impact and recovery of marine life over time, increasing video monitoring from once a year to at least monthly, and a regional planning review.