17 October 2011 Last updated at 21:43 ET

Coastal farm ban urged to protect wild fish stocks

Fish farming could be banned in some coastal areas in a bid to protect wild fish stocks, BBC Scotland has learned.

Anglers and landowners have claimed that parasites from farms are at least partly to blame for declines in wild salmon and sea trout.

Now the Scottish government may follow the example of Norway and restrict the spread of farms.

The fish farming industry said there was no evidence that parasites were threatening wild fish stocks.

Environment Minister Stewart Stevenson was interviewed as part of a BBC Scotland investigation into fish farming.

When asked if new legislation planned for later this year might see farms banned from areas that are important to wild stocks, he replied: "Of course it may do - and we'll consult on that. Everything is open for discussion.

"But we have to have the consultation, we have to understand in the environment we have in Scotland what the effects of different options would be."

Mr Stevenson also revealed he is considering forcing salmon farmers to publish information about lice levels on specific farms, a measure which has been called for by critics of the fish farm industry and which has been implemented by the Norwegian government.

However, Steve Bracken from Marine Harvest, Scotland's largest salmon producer, said there was not enough evidence to suggest that parasites - known as sea lice - were responsible for any declines in wild fish stocks.

He argued producers should not be forced out of existing farming areas.

"We can't say that we're not having an impact. It's just knowing how much of an impact we've got," he said.

"And that's why I think it would be wrong to say 'well, we don't know, we don't really like this but we think you should go out of the loch'. We don't think that's a reason for moving."

The BBC Scotland Investigates: Scotland's Fishy Secrets programme also examined whether lice have become resistant to the range of chemicals being used to treat them and revealed evidence that the industry may be hiding the scale of problems it has encountered in treating the parasites.

During the investigation, BBC Scotland made a Freedom of Information request to the Scottish government.

The response contained notes of discussions between the drug companies that make the treatments and government officials.

In those documents a government official writes: "The view from the [fish farming] industry was that there is a clear evidence of lack of efficacy and that some fish farms have even been closed as a result of sea lice infestation. However, fish farms are reluctant to report these officially."

In another document relating to the Veterinary Medicines Directorate (VMD) which is responsible for monitoring residues of drugs in food, a government official reports: "The [fish farming] industry, the pharmaceutical companies and the VMD are therefore in a Mexican standoff."

Lice burdens

The group which represents salmon farms in Scotland said the industry was not concealing information from regulatory authorities.

Scott Lansburgh, chief executive of the Scottish Salmon Producer's Organisation, said: "We're regulated by the environmental protection agency, SEPA.

"So they keep a close eye on what's going on in the industry as do the fish health inspectorate and their reports are open to all to see and we're regularly reported on and we're regularly inspected so we're not hiding anything."

Environment Minister Mr Stevenson was also asked about the scale of the problem.

He said: "At the moment there isn't evidence of resistance to the various treatments there are, some other countries have that resistance if you continuously use the same treatment."

The wild fish lobby said that any resistance could have serious implications.

Guy Linley Adams, a lawyer working for the Salmon and Trout Association, said: "If we're getting resistant sea lice we need to know where the populations of those resistant sea lice are.

"If it does spread we get multiple resistance in sea lice across the west coast of Scotland and in the isles then you've got this awful scenario of farms with huge lice burdens causing problems not just for the farmers but for the wild fish as well."

BBC Scotland Investigates: Scotland's Fishy Secrets will be broadcast on BBC One Scotland at 22:35 on Tuesday 18 October, and then on the programme website.