Remote harbour salmon farms record 1000-tonne deaths

Fish farming in Macquarie Harbour, the home of the endangered Maugean skate, is under review. (HANDOUT/IMAS)

The death of more than 1000 tonnes of salmon over seven months at farms in a remote harbour "devastates" claims of a sustainable industry, environmentalists say.

But an aquaculture head says the figure is a consequence of the size and scale of operations.