The plans by Defra call for a new Border Rivers Order which would make significant changes to the management of rivers in parts of the region.
The proposals for such an Order for the Border Esk (the rivers around Newcastleton and Langholm) give the English Environment Agency significant powers over policing several key rivers in the South of Scotland, leaving the control of the Scottish Ministers altogether.
Commenting on the move, John Lamont MSP said: "This proposed new regulation is a real concern to many people in the local community and raises significant questions about the management of these local rivers.
"The drive to have one body responsible for the management of the rivers means that the obligation to consult Scottish Ministers on by-laws will be removed.
"The impact of the change would mean that, for example, anyone caught fishing without a rod licence in Newcastleton or Langholm could be prosecuted across the border in Penrith without any reference to the Scottish court system or Scots law."
"These changes have the potential to undermine the integrity of the Scottish authorities in policing these rivers and the Scottish legal system in bringing about prosecutions for offences committed on Scottish rivers.
John added: "It is disappointing that these proposals take so little account of Scottish interests on the rivers. The fishermen using the rivers around Newcastleton and Langholm should be treated in exactly the same way as those fishing rivers in any other part of Scotland."