Truth or Fiction?
Seals are reported to devastate salmon farm stocks, but what are the alternatives to killing them and do they work? Biologist David Ainsley reveals the truth.
Do seals need to be culled to protect salmon stocks in Scottish waters?
THE SHORT ANSWER IS NO. It is certainly true that seals can damage nets and kill salmon in Scottish waters; salmon producers say they cause “millions of pounds’ worth” of damage every year. But they also accept that shooting seals should only be an action of last resort and say they aspire for it to become unnecessary. They have made progress towards this goal in recent years: they say 49 seals were legally shot in 2017, an 84 per cent reduction on the number in 2011.
David Ainsley, a marine biologist who operates a tour-guiding business on Scotland’s west coast, says shooting seals would be completely unnecessary were salmon farmers to use double netting to contain their fish, as they do in British Columbia.
Ainsley believes there is a bigger issue at stake, however. Many salmon farms – 121 out of 172 listed by Marine Scotland – routinely use acoustic deterrent devices (ADDs), which send out blasts of noise to keep seals away from fish pens. He says this either damages the hearing of seals and European protected species such as porpoises, dolphins and whales, or forces them to abandon whole areas because of the noise. “These ADDs can cause disturbance, stress and hearing injuries,” Ainsley says. “And for echo-locating mammals [such as porpoises], hearing injuries are a death sentence.” One study found that the use of ADDs had excluded porpoises from 87 per cent of a 990km2 area of sea.
Ainsley has submitted a complaint to the European Commission about the use of ADDs because he says they contravene both Scottish and European legislation. Scottish Natural Heritage states: “In Scottish inshore waters, it is an offence to intentionally or recklessly kill, injure, capture, disturb or harass a cetacean.”
The Scottish Salmon Producers Organisation (SSPO) says its members adhere to a code of practice, which recommends the use of ‘seal blinds’ (to prevent seals from seeing the fish at the bottom of the pens), heavy tensioning of the nets and ADDs. “The damage seals cause to salmon is severe and extensive, killing many by taking single bites out of each fish then leaving them to die,” said the SSPO in a statement.
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Shooting seals would be completely unnecessary were salmon farmers to use double netting.
Producers say the damage seals cause to salmon can be extensive.