SCOTLAND’S seas must not be treated like an “open sewer”, a campaigner has said as more than 42,000 call for greater salmon farm scrutiny.

Don Staniford, director of Scottish Salmon Watch, said a lack of effluent testing could allow parasites, chemical waste and more into open waters.

The comments come as advocacy organisation SumOfUs prepares to hand over a petition signed by more than 42,000 calling for the Scottish Government to impose a mandatory testing regime to prevent salmon farm waste compromising the ecosystem.

The push comes four months after the BBC reported that Cooke Aquaculture had discharged untreated blood water into Mid Yell Voe, Shetland, something the company denies.

It also follows similar SumOfUs action in Canada, where ministers took action over environmental concerns.

Sondhya Gupta , senior campaigner at SumOfUs, said: “People all over the UK want to see Scottish wild salmon protected. The government needs to act.”

Staniford said the “pristine marine environment” was being used “as an open sewer”, adding: “In view of the recent results of positive tests for viruses in effluent water in Canada it is incumbent upon the Scottish Government and SEPA to follow suit.”

The Scottish Salmon Producers Organisation says existing regulations, daily checks on fish health and performance audits by watchdog SEPA ensure “high standards” are met.

Meanwhile, the Scottish Government says the risk of disease transfer from farmed to wild salmon is “low” and it is “committed to protecting Scotland’s environment”.