Salmon farmers face "huge unnecessary burdens" and a loss of market share under UK government plans for Brexit.
The chief executive of the Scottish Salmon Producers Organisation (SSPO) said firms were being told to prepare for trade barriers with the EU.
The industry is also warning that added red tape could see £9m on costs and delays to the departure of fresh fish.
The UK government said it would inform producers later this year on the measures they needed to take.