Shares in Tassal have dropped as the salmon producer again defended its farming practices in the wake of an ABC Report questioning the sustainability of the industry.
Tassal shares fell nine cents or 2.3 per cent to $3.76 on Tuesday.
The fall came as a substantial holder of Tassal shares, Tribeca Investment Partners, sold $3.78 million in stock.
Meanwhile, shares in rival salmon farmer Huon Aquaculture lifted 17 cents, or 4.7 per cent, to $3.80.
Tassel said on Tuesday that a Four Corners report aired by the ABC on Monday on the sustainability of the industry in Tasmania had "misled consumers, investors and the Tasmanian community".
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Four Corners reported there had been concerning temperature spikes and dangerous drops in water oxygen levels this year in Macquarie Harbour, where Tassal, Petuna Seafoods and Huon Aquaculture intensively farm salmon.
Huon has broken ranks and warned the state government that fish stocks need to be reduced in the harbour.
But Tassal managing director and chief executive officer Mark Ryan says he is disappointed the program had not properly considered the "relevant science".
"Four Corners relied on a single, competitor-directed research study to draw generalisations about Tassal's and wider operations in Macquarie Harbour," Mr Ryan said in a statement on Tuesday.
"I am at a loss as to why Four Corners deliberately focused on a scare campaign which largely relied on anecdotal evidence and the beliefs of our commercial competitor in an attempt to make a case against Tassal and the Tasmanian salmon industry."
The ABC report quoted research by Melbourne University's Associate Professor Tim Dempster, which was funded by the Fisheries Research Development Corporation.
It suggested conditions in Macquarie Harbour last summer consistently breached the maximum levels salmon can withstand without experiencing sub-lethal stresses and mortalities.
Environment Tasmania on Tuesday called on the state's Primary Industries Minister Jeremy Rockliff to conduct an open review of salmon industry regulations.
But the minister says the system has already been overhauled so that the Environment Protection Agency regulates the industry, including the stocking cap in Macquarie Harbour.
He echoed Tassal's complaint the ABC report was based on selective science.
"Four Corners did not include the full range of scientific information available on the industry and that's disappointing," Mr Rockliff said in a statement.
Tasmania's salmon industry was among the best regulated in the world, the minister said.
