The River Tweed Commission (RTC) has warned current water scarcity plans are inadequate to protect its fish stocks.
It is concerned at the “significant problems” being created by low water levels and high temperatures on Atlantic salmon, sea and brown trout.
The group wants a review of the system still allowing water extraction from the river by industry and agriculture.
The Scottish government said it worked closely with experts to decide what actions to take to tackle scarcity.
There have been a series of water scarcity warnings from the Scottish Environment Protection Agency (SEPA) so far this year with the east of the country more badly affected than the west.
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