Opportunity Knox
While all manner of methods – from expensive predator nets, to surrounding the cage with enough acoustic deterrent devices to power the main stage at Glastonbury – have been trialled to keep seals away, it seems that a comparatively simple combination of two different designs of plastic netting is currently proving both incredibly effective and relatively cheap.
The combination in question is a net made by W&J Knox, which combines their soft, small mesh ‘Star net’ on the inside with the tougher ‘Sapphire Ultra-core’ on the outside. The net was made to a Knox design, but the netting was developed and produced by Knox's Indian partners ,Garware Wall Ropes.
Trialled by Scottish Sea Farms in one of its cages at its Loura Voe site, which has been plagued by seals over the years, since January the producer has been so impressed that it has already decided to replace the nets in all 10 80-metre pens at both Loura Voe and nearby Grunnavoe with the new arrangement.
Kimberley Izdebski (pictured above), site manager at Loura Voe – and the first ever female site manager in Shetland – has been supervising the net changes and reflects: “We’ve been using 20 Mohn Aqua projectors to try to keep the seals out, but while these certainly make a difference, it seems the seals return when their hearing comes back to normal.
“The stress from the seal attacks has meant that there have been a number of lean fish this generation but within a month of installing the new nets the fish put back on their condition.”
And, while keeping seals out may have provided the original impetus for the new installation, it also happens to tie in neatly with the company’s decision to deploy lumpsuckers in 8-10 of the cages between the Loura Voe and Grunnavoe sites this autumn, as the star net’s 18mm mesh is small enough to keep the cleaner fish in the pens.
“The first batch of lumpsuckers will be provided by Ardtoe in mid-September,” Kimberly explains, “will be stocked at between 10 and 15% [of the salmon number per cage] and will be monitored and looked after by a dedicated lumpsucker specialist on site.”
