A salmon company is being investigated by a peak animal welfare body after a video showed workers sealing live, twitching fish in a tub.
The footage was taken by the environmental group, the Bob Brown Foundation, on Wednesday at a Huon Aquaculture lease in the D'Entrecasteaux Channel in southern Tasmania.
Salmon farms in the region have in recent weeks experienced elevated mortality which has largely been blamed on a bacterial disease.
The video, which shows moving salmon being siphoned out of a pen and sealed in a tub with dead salmon, has prompted calls for Huon Aquaculture to lose its RSPCA accreditation.
The company has pledged a full investigation into the matter, telling the ABC the vision did not depict standard operating procedures.
Huon Aquaculture has RSPCA-approved certification, and according to its website is committed to placing fish health and welfare at the centre of farming operations.
The RSPCA has described the vision as "incredibly concerning".
"The inhumane handling of live, sick or injured fish as shown is completely unacceptable," a spokesman said.
"The RSPCA-approved certification body is, as a priority, seeking further information from Huon about how something like this could have happened.
"Based on this and any other information provided (we) will consider what action is required in line with our processes."
The Tasmanian Greens, the Bob Brown Foundation and a community anti-salmon farming group say the footage calls into question the animal welfare credentials of the industry.
"It is now clear that the RSPCA has no choice but to drop their certification of this toxic and cruel industry," foundation campaigner Alistair Allan said.
"The footage of live fish being sealed in a tub and left to suffocate would shock anyone, let alone an organisation dedicated to the prevention of cruelty."
Tasmania's Environmental Protection Authority recently said it doesn't know the exact number of salmon deaths because the industry isn't required to report the weight of mortalities until later in March.
Greens leader Rosalie Woodruff says credible estimates suggest millions of fish have died.
Tasmania's Liberal Premier Jeremy Rockliff, whose party supports the industry, has told parliament salmon farms are "on notice".
"I expect the highest possible degree of accountability and transparency ... because it is in Tasmania’s brand interest and (the) industry’s interest as well," he said.
"The current salmon mortality event is largely due to endemic bacteria which does not grow in humans and does not present a human or animal health or food safety risk.
"From an environmental perspective, the critical issue is timely management and collection of fish residue in an improved manner."
Chunks of farmed salmon have washed up on beaches in the state's south in recent weeks.
Huon Aquaculture and the Environmental Protection Authority have been contacted for further comment.
