SALMON farmers are turning Scotland's pristine seas into an “open sewer”, it has been claimed.

Campaigners want Scottish officials to routinely test the waste being pumped out of farms for viruses and diseases.

They say wild salmon are being killed off by sea lice and other diseases which are plaguing commercial fish farms.

Consumer group SumOfUs will deliver a 41,630-strong petition to Holyrood today, calling on the Scottish Government to bring in stricter rules.

Senior campaigner Sondhya Gupta said the farms supplying salmon to supermarkets such as Sainsbury's and Tesco made millions of pounds every year.

She added: “The appalling conditions in their farms and processing plants are also putting wild fish at risk of disease and infestations like sea lice.”

Don Staniford, director of Scottish Salmon Watch, said: "Salmon farms use Scotland's pristine marine environment as an open sewer.

"The public would be outraged if any other industry was allowed to spread chemical wastes, parasitic lice and potentially deadly viruses and pathogens directly into coastal waters.”

It comes as the Scottish Greens demanded a moratorium on further fish farms in Scotland until new regulations are put in place.

Environment spokesman Mark Ruskell MSP said: “If the Scottish Government wants to double the size of the salmon farming industry, then ministers should fund independent research and regulation to protect the environment that our coastal communities rely on.

“Given the rapid expansion of this industry, it's simply unacceptable that our environmental regulator has no independent research budget to examine its impact and has had to reduce its own laboratories from eight to two.”

First Minister Nicola Sturgeon previously said she had “concerns about aspects of fish farming”.

Mr Ruskell added: “If the government has ‘issues of concern’ about salmon farming in Scotland, then it must put a moratorium in place to halt expansion until the many environmental concerns can be independently assessed."

Rural Economy Secretary Fergus Ewing will appear before a Holyrood committee today to discuss salmon farms.