Want to read more?
We value our content and access to our full site is only available with a subscription. Your subscription entitles you to 7-day-a-week access to our website, plus a full digital copy of that week’s paper to read on your pc/mac or mobile device. In addition, your subscription includes access to digital archive copies from 2006 onwards.
Just want to read one issue? No problem you can subscribe for just one week (or longer if you wish).
Scottish Sea Farms (SSF) has defended its new £6 million boat fitted with a state-of-the-art thermalicer after concern was raised about heating salmon.
The 26-metre purpose-built vessel – the first of its kind to be built in Scotland, and on a
long-term lease to Scottish Sea Farms – was built with the help of a £205,000 Marine Scotland grant= towards £2.5million worth of thermalicing kit to help intervene earlier in sea lice control.
However, a story in The Oban Times about the boat, due in Shetland in early May to be fitted out before it gets to work, prompted some concern over the thermalicing method.
Campaigner Dennis Archer from Argyll’s Green Party said Norway announced in 2019 that this method of controlling sea lice with a water treatment above 28⁰C was to be phased out over two years ‘because of the cruelty to the fish’.
‘It is not in the nature of salmon to enjoy being heated alive,’ he said, describing it as ‘a damaging treatment’.
‘Open cage salmon farming is not possible without causing sea lice problems and therefore damaging fish welfare.
‘Those of us who live and work here have a duty to maintain an unpolluted, biodiverse environment for future generations and not to exploit it for personal gain.’
SSF’s head of fish health, Dr Ralph Bickerdike said treatments such as thermo delousing are carried out specifically to protect fish welfare, removing lice just as is done with other farmed livestock.
‘The fish pass through lukewarm water for less than 30 seconds. This is water 20°C above ambient seawater temperature to a maximum of 34°C; a parameter informed by work published by the Norwegian Institute for Marine Research showing that exposing 2.5-3kg salmon to seawater up to 34°C for a maximum of 30 seconds did not cause undue harm or stress.
‘The result is up to 95 per cent lice clearance with minimum handling and duration, demonstrating that, just like taking your cat or dog to the vet, the long-term health and welfare benefits outweigh any potential short-term discomfort,’ added Dr Bickerdike.
A spokesperson from the Scottish Salmon Producers Organisation (SSPO) said thermalicers are an important tool for managing the health of Scottish salmon without the need to use medicines.
‘As with human health, it is important that fish veterinarians have as many treatment options available as possible to respond to a variety of situations,’ said the spokesperson.
On Monday Scottish Sea Farms, which is seeking permission from planners to extend its operation at Dunstaffnage, responded to other concerns after what looked like a slick was spotted near Ganavan and was reported, with photographs on Facebook over the weekend.
Scottish Sea Farms put the change in the sea surface down to a natural phenomenon known as the Marangoni effect, caused by breezy weather.
SSF’s regional manager for mainland Scotland, Innes Weir, said: ‘The sea surface change was simply down to breezy weather conditions creating what is known as a wind or tidal shadow; a natural phenomenon that could be seen around the area including at Dunstaffnage and Oban Marinas, and at our own farms.’