Catch limits will be set for key shellfish species to prevent and deter unlicensed fishermen from selling their catch illegally.
The Scottish Government said it will work with buyers to ensure they comply with regulations to prevent unlicensed commercial fishing.
Fisheries Secretary Richard Lochhead said: “We have heard from the industry about the detrimental impact that unlicensed fishing is having on our fishermen.
“These measures will help clarify the situation for fishermen.
"We want to make sure that those who operate unlicensed fishing vessels and who chose to sell their catches are aware of the need to have a licence and the consequences of not having one.
“I intend to review the measures to monitor their effectiveness and look to introducing further measures if necessary.”
New measures target unlicensed fishing
2 February 2016