Do “Anti-predator nets” protect seals as well as salmon?

Just one in five salmon farms in Scotland has installed the most effective method of deterring seals, data reveals, prompting fresh criticism of claims that the animals are shot as “a last resort”.

Scottish environment secretary Richard Lochhead has said that 80% of salmon farms do not use anti-predator nets to prevent seals attacking salmon cages.

While all sites in Scotland are fitted with some form of seal deterrent, evidence suggests that anti-predator nets, which encompass the entire farm and provide a first wall of defence against marine predators, are the most effective, and at an average cost of £1m to install, the most expensive.

The latest data on seals shot by salmon farms, covering January-July of this year, shows that Grieg Seafood, which has fitted anti-predator nets at its farms, killed one seal. Companies that have not fitted anti-predator nets have shot many more. They include Marine Harvest, which killed 15 seals, Scottish Sea Farms (12) and the Scottish Salmon Company (11).

Compared with the same period last year, the number of seals shot by salmon farms in Scotland rose 20%, although ministers insist that the overall trend is down, with a 55% reduction in seal shooting over the past four years.

Anti-predator nets are the most effective deterrent for salmon farms but cost £1m to install.

Campaigners have renewed calls for bodies such as the RSPCA to withdraw their endorsement of farmed salmon produced by firms that have not installed the nets and protests are planned next month in London and outside the RSPCA head office in Sussex.

“The price for seal-friendly farmed salmon is the installation of predator nets and that could be £1m for each salmon farm,” said Don Staniford, an environmental campaigner. “Given that there are 143 active salmon farms in Scotland and one in five have installed them, the cost to the Scottish salmon farming industry could be well over £100m. Until all salmon farms install predator nets, consumers should boycott all Scottish salmon.”

Lochhead outlined the position on seal deterrents in a letter to Roderick Campbell MSP, who recently led a members’ debate in the Scottish parliament on the declining seal population.

An increasingly popular option at farms is to fit the bottom of nets with blinds that hide salmon from seals.

“All fish farms included in applications for a seal licence already employ at least one, and many a range of, non-lethal alternatives,” wrote Lochhead. “All use tensioned nets, almost half use acoustic deterrents, a third use seal blinds, and a fifth use anti-predator nets.

“The use of such measures has contributed to an overall reduction of 55% in seal shooting since the system was introduced in 2011.”

In correspondence with Staniford, Campbell wrote it was “deeply unfortunate that some salmon farms consider it necessary to shoot seals. I recognise the need to protect very valuable fish stocks, but I also appreciate that this should not come at the cost of the lives of seals.”