Know your Scottish Salmon

What future sea lice? Part I: Cleaner fish.

A summary of the Marine Conservation Society’s Briefing Document on Cleaner Fish submitted to the inquiry on The Environmental Impacts of Salmon Farming conducted by the Scottish Parliament’s Environment, Climate Change and Land Reform Committee.

Sea lice cause major health issues for farmed salmon. The treatment of them is currently dependent on a range of anti-parasitic chemical treatments, both bath and in-feed. The continued reliance and discharge of these chemicals combined with concerns about increasing resistance to their efficacy has led the salmon farming industry to introduce biological sea lice control with the use of cleaner fish.

Ballan wrasse and lumpfish are the predominant species used as cleaner fish, with a current heavy demand placed on wild capture fisheries to fulfil this demand despite the advent of farming for both species. However, wild capture cleaner fish have no legislative fisheries management measures in place to ensure their sustainable exploitation and to maintain healthy populations. Welfare of cleaner fish during capture, storage, transport and deployment is also a concern.

Voluntary Codes of Practice for wrasse management developed in England that addressed some of the issues of concern and it has been recommended that similar measures be adopted in all wrasse fisheries.  Marine Scotland recently published voluntary control measures for the live capture of Scottish wild wrasse for salmon farms, which can be accessed through the Scottish Salmon Producers Organisation website.

An anticipated 50 million cleaner fish will be required by 2020, with most if not all of these coming from farmed sources. It is therefore imperative that best practice is defined and applied to their production.

With the use of one cleaner fish per 25 salmon, the use of cleaner fish also represents a significant fish protein source that is currently not used at the end of production cycle, equating to a significant protein loss. To mitigate this the Marine Conservation Society would like to see a market being developed and the wrasse being utilised rather than slaughtered and discarded.