The Scottish government tried - and failed - to avoid a US import ban on salmon from fish farms that shoot seals, it has emerged.
New US rules will ban imports of fish from farms which kill marine mammals, including seals.
Emails have emerged showing officials attempted to seek an exemption for Scottish fish farms.
Government figures show salmon farms, which are licensed to kill seals, have shot more than 800 since 2011.
Fish farms are licensed to kill the animals to prevent them from attacking and eating salmon in the farm cages.
The US adopted new rules last year, however, forcing exporting nations into meeting the US standards on marine conservation.
The US is the world's largest importer of seafood, buying about $20bn of product every year, including Scottish salmon worth £193m last year.
The campaign group Salmon Watch Scotland obtained the emails under Freedom of Information laws.
In them, officials from Marine Scotland argued that the industry in Scotland was "very different from fish farming in the US".
They pointed out that the rules in Scotland do not allow the "reckless" shooting of seals, and that the intention is not to reduce the overall seal population.
They also argued that shooting individual seals is a measure of "last resort".
However, the efforts were unsuccessful, with the US National Oceanic and Atmospheric Administration (NOAA) listing Scotland's industry as being officially covered by the ban.
About 150 fish farms in Scotland are likely to be affected by the ban.
Campaigner Don Staniford, from Scottish Salmon Watch, called on Scottish ministers to end the licensed killing of seals.
He told the Sunday Herald: "If Scottish salmon farmers want to export to the US they must stop slaughtering seals - no ifs, no buts, no bullets," he said.
"Shamefully, the Scottish government has been working behind the scenes in a desperate attempt to wriggle off the hook but their attempts have failed dismally.
"Rather than protecting the lethal Scottish salmon farming industry the Scottish government should be protecting seals."
Cabinet Secretary for the Rural Economy Fergus Ewing told the BBC's Sunday Politics Scotland programme he hopes the killing of seals may become unnecessary in the near future.
He said: "We are working with the sector towards a situation where licences for the control of seals would no longer be necessary and are doing everything possible we can to ensure that the best environmental practice is followed and that we can use modern technological devices to scare the seals away from cages."
A Scottish government spokesperson said: "We are in regular dialogue with Defra and the EU around the future application of the US mammal regulations, including how these would interact with our seal licensing regime in order to ensure compliance going forward.
"We have also been raising awareness of the regulations and their potential impact on Scottish seafood exports with Scotland's aquaculture sector."
Mark Ruskell MSP, food and farming spokesman for the Scottish Greens said he was pleased the government's attempt to secure an exemption had failed.
He said: "This was a desperate attempt to prop up the bad practice of an industry which is failing in its responsibilities to protect the environment.
"The control of seals by slaughter is unnecessary. If the government wants to avoid the collapse of a huge market for Scottish salmon, it must change the law to ban the intentional killing of seals by fish farms."