Sea Lice Ronnie Soutar
Scottish salmon farmers collaborate to combat common threat
AS we move into a new decade and, with Brexit now a reality, a new era for Scottish salmon farming, one factor remains unchanged: sea lice continue to be a significant threat. New challenges come and, sometimes, go but the Auld Enemy remains constant! We do, however, have a greater armoury than ever on our side in this fight and 2019 saw some significant victories.
An increasing number of sites report having produced a crop without ever having a treatment intervention, either medical or physical. This is proof positive that preventative measures and biological control really are having a significant impact.
There is, of course, still a lot of work to be done in improving these measures and, indeed, adapting them to changing conditions.
Some of these changes we impose upon ourselves – in particular, the move towards virtually year-round smolt movements puts pressure on long-standing management areas and the fallow periods which are key to breaking the lice lifecycle.
It has been really heartening to see the level of inter-company cooperation and dialogue going into ensuring that this potential problem is not allowed to become a real issue.
Information sharing has also been key in the ongoing development of physical treatments. As we bring new systems into play, it is vitally important that we find the best possible ways to use them on Scottish farms.
The industry is sharing experience and making available all data on best practice, which is central to us moving forward together.
More than this, there is genuine desire between companies to actually share physical assets. This is particularly important as in 2019 we saw equipment shortage (at a national level) and logistical difficulties in deployment as negative factors in lice control.
With the best will in the world, and with genuine commitment to investment, there is a limit to how rapidly Scotland can gear up with new treatment technology.
There is no doubt that, at the most senior level, Scottish farming companies recognise that lice are a common threat, and collaboration in their control far outweighs any perceived competitive advantage in treatment developments. In this arms race there is absolutely no doubt that lice, not other farmers, are the enemy !
It goes without saying that any joint approach must not compromise biosecurity: it would be madness to control lice at the risk of spreading other pathogens.
The Code of Good Practice has served us well in this respect but 2020 may be the time to review protocols in light of factors such as increased movement of physical assets between farms and, indeed, across regions.
We also have to keep up our focus on fish welfare. Over the last year, further concerns have been raised about the negative impacts of some physical treatments on fish.
Some comments are behind the curve; while it seems true that unacceptable losses occurred during the introductory phase of new technologies,
lessons have undoubtedly been learnt.
The vast majority of treatments are now carried out with confidence and with minimal impact on the fish.
However, genuine concerns have been raised by serious scientists and these should not be ignored. In particular, evidence that thermal shock can cause suffering has led the Norwegian authorities to consider whether heat-based treatments are justifiable.
It is crucially important that work on this progresses and focuses on the conditions experienced by fish in actual treatments, rather than in experimentally exaggerated conditions.
There also has to be a cost-benefit analysis: not fi
We enter this new decade with genuine optimism that lice control is turning from aspiration to reality”
nancial cost but welfare cost – comparing any transient pain with the long-term gain from the fishes’ perspective.
There are virtually no treatments which have no negative effect (ask anyone who has ever had an injection!) but the concept of balance is well embedded in veterinary practice and should be at the centre of this discussion.
Similarly, the welfare of cleaner fish must be front and centre to their continued deployment. The farms which are achieving best results with biological control are doing so largely because they are focusing on cleaner fish husbandry.
Again, the sharing of best practice is key and is happening across the industry, in meetings and conferences.
Perhaps more importantly, it is happening informally, at ground level. Conversations between those directly involved in looking after cleaner fish, both within and between companies, are making a big difference to how quickly improvements are happening.
While we can never be complacent, and although progress can be frustratingly slow, we enter this new decade with genuine optimism that lice control, in a welfare friendly manner, is turning from aspiration to reality.
Cooperation is the key and the SSPO’s group of the vets, who have the industry’s stock under their professional care, remains a very good example of how we can work together for the common good.
Left and above: Sea lice
Right: Checking the salmon for lice