Predator nets help cut seal culling

SCOTTISH Sea Farms has released its seal culling figures for the past year, which show a drop of 31 per cent on 2017, from 16 to 11.
The company, which has 45 salmon farms around Scotland’s west coast and islands, has installed Sea Pro anti-predator netting, supplied by W&J Knox, at 21 of its farms at a cost of £4.2 million.
It said it had plans to equip a further nine farms – specifically those facing a seal challenge – in 2019 and 2020 at the start of each new crop cycle.
At the company’s seven farms in Orkney, where the new protective Sapphire Seal Pro nets were first trialled in 2016 before being rolled out, there have been no seal culls in almost three years.
Seal culling is the last resort option taken by farmers and is carried out under licence only when seals persist beyond all other preventative measures.
Legislation in the US will soon ban the import of any seafood that has been produced in contravention of strict rules on animal welfare, which prohibits the shooting of seals. This ruling has the potential to end lucrative salmon exports to North America from farmers still culling predators.
Scottish Sea Farms’ head of fish health Ralph Bickerdike said: ‘Our priority has been to install Seal Pro nets at those farms with a historic seal challenge.
‘The speed with which we can do this, however, is dictated in large part by nature as there are limited opportunities in the growing cycle where we can install the new nets without risking stress to our salmon. The ideal time is ahead of each new crop.
‘On occasion, we have installed Seal Pro netting at one farm only to see seals relocate to another farm where there had been no prior seal challenge.
‘This, we believe, accounted for five of the 11 seals culled in the last reporting period and is further reason why we will continue to roll-out the new netting until each and every farm is protected.’
Securing the nets in place are individual weights placed at 5m intervals or a circular sinker tube at the net base, which increases tension, prevents the netting from flexing and reduces potential entry points for seals.
Now being widely adopted across the sector, protective netting, along with the use of acoustic deterrent devices, has contributed to an 81 per cent drop in the number of seals culled by salmon farmers since 2011.
Unlike traditional nylon nets, which are treated with a copper based anti-foulant to protect against marine growth, Seal Pro nets require no such treatment.
Engineered from high density polyethylene, they have a stronger frame that can withstand regular cleaning in-situ and a smoother surface that is harder for marine organisms to adhere to and is also easier to clean.
Jim Gallagher, managing director of Scottish Sea Farms, said: ‘It’s has been a long-standing goal of ours to use zero copper on our nets, taking us beyond SEPA compliance, and the continued roll-out of Seal Pro netting takes us a step closer to achieving that goal.
‘We’ve also invested significantly in new technology that means each Seal Pro net can be cleaned in just over an hour, ensuring a pristine growing environment for our salmon.’