© Scottish Sea Farms
As well as the bigger pens and heavier moorings, the site off Mull – called Fishnish A – also introduced Midgard HDPE knotted nets and a new winch system, and trialled a smart feeding regime, in an investment of around £3 million.
Farm manager Alastair Fraser told Scottish Sea Farms' newsletter, The Source: “It was night and day compared to the previous set-up: so simple, less labour intensive, with less manual handling. The new winch system is another world and once we got the hang of it there was no going back.”
In the new setup, ten winches are fitted to each pen’s walkway for times – such as harvest – when the nets need to be lifted. These can be operated remotely from a dedicated workboat, providing better net control and improving staff safety.
“Dealing with three instead of 10 pens (we kept one spare for handling or freshwater treating) allowed us to stay focused on the task in hand and carry out any treatments much faster,” said Fraser.
The combined tonnage for Fishnish A and B, where half the crop was moved after six months, was just over 4,000 tonnes, said Fraser, despite challenges such as micro jellyfish that affected most of the sector between 2022 and 2023.
Fraser attributes the results to good husbandry as well as to the bigger pens, which provide lower stocking density and better water flow and oxygen.
The new feeding system, involving motorised smart spreaders, produced "fantastic results", according to Fraser - ensuring the whole population was fed swiftly, at the same time - thereby allowing the salmon to spend more time lower in the pen, where they are less exposed to environmental issues such as sea lice and algae.
With the fish harvested over summer, the team is now preparing for the next cycle and hoping to roll out similar infrastructure at neighbouring Fishnish B. And while they will do some things differently, such as increasing the ratio of wrasse in the pens to better handle sea lice off Mull, they are convinced the new infrastructure has paid off .
“The team realised they’d had a hard crop but saw the benefits of this new way of farming and morale was definitely better,” Fraser added.
