A cut in migration as a result of Brexit could cost Scotland's economy up to £10 billion a year by 2040, new analysis warns.
Scottish Government research concludes that lower migration would reduce real gross domestic product (GDP) by 4.5% in Scotland, the equivalent of almost £5 billion a year, compared to 3.7% across the rest of the UK.
If net migration was reduced to tens of thousands as per a UK Government pledge, the cost north of the border could be £10 billion per year by 2040, the paper found.
The Scottish Government said that with the number of deaths expected to outweigh the number of births for every year until 2040, action was needed to maintain and grow Scotland's working age population and meet the needs of rural communities.
The research concluded that "given the considerable larger negative impact on Scotland's economy, there is a strong economic case for additional immigration powers in Scotland".
The paper sets out options for a Scottish migration system, including specific criteria to address skills shortages, a new migration body and powers to make it easier for migrants' family members, and those of UK citizens, to join them in Scotland.
External Affairs Secretary Fiona Hyslop said: "It is clear that the UK Government's plans to reduce migration would not support Scotland's economy or our population needs - all of Scotland's population growth over the next 25 years is projected to come from migration.
"So this paper sets out what a devolved migration system could look like, and the principles we would follow.
"Inward migration does not just bring economic benefits. By welcoming people to live, work and study in Scotland we can strengthen our society and enrich our lives.
"Migrants contribute to our economy by bringing new skills and fresh approaches. Without their contribution Scotland's economic growth will suffer.
"Scotland's economy is heavily reliant on inward migration - particularly of workers with the skills we particularly need.
"This paper demonstrates that it simply does not make sense to set arbitrary targets to reduce net migration, or to end free movement of people by leaving the single market.
"There is now an overwhelmingly strong case for Scotland to have the power to tailor its own migration policy to reflect its own unique circumstances.
"Indeed, there is a growing consensus that this is the only logical step in the face of UK Government policy which is determined to restrict the number of people who can choose to make Scotland their home."