A new offence of introducing live fish or live spawn of fish to inland waters without the proper permission is to come into force on 1 August.
Scottish government authorities will have to be satisfied that there is an acceptable case for stocking fish which will not threaten native Scottish species, before permission is granted.
Cabinet Secretary for Rural Affairs and the Environment Richard Lochhead said: "Our rivers and lochs support a unique range of fish and other aquatic species.
"We have already taken steps to limit alien invaders through the Non-native Invasive Species Strategy launched earlier this month.
"The legislation I am announcing today provides the Government and District Salmon Fishery Boards with a powerful tool to protect Scotland's unique and fragile freshwater biodiversity, while continuing to promote the world-renowned fishing it supports."
The new provision will make it an offence for any person, without the written consent from the appropriate authority, to intentionally introduce or stock any live fish or live spawn of any fish into inland waters in Scotland or to be in possession of any such fish or spawn with the intention of introducing it into inland waters.
Where a District Salmon Fishery Board (DSFB) operates and the fish to be introduced are salmon or sea trout then the relevant Board will take applications from individuals or corporate bodies who wish to introduce fish. The Board will issue written agreement or refusal to the applicant.
Where a DSFB does not operate or where the fish being introduced are not salmon or sea trout then it is for the Scottish Ministers via Fisheries Research Services (FRS) to consider applications from individuals or representatives of corporate bodies who wish to introduce fish and issue written agreement or refusal.
The provisions apply to all introductions of freshwater fish including, salmon, trout and coarse fish to any inland Scottish water system. These provisions do not apply to fish farms or to ornamental fish-keeping facilities.
A risk-based assessment procedure will be used by both authorising bodies when considering proposals to introduce or stock fish, whether salmon, sea trout, brown trout, rainbow trout or coarse fish.
There will be no charge for applicants.
Greater Protection for Native Fish
SCOTLAND - Scotland's precious native freshwater fish life is to receive greater protection from alien species.