Optimised production, nutrition and use of the cleanerfish Ballan wrasse (Labrus bergylta).

Salmon lice infections pose a serious threat to the sustainebility of the salmon industry in terms of fish welfare, environmental impacts and economic profitability. The situation has recently become more serious due to appearence of lice populations with reduced sensitivity to medical treatment. The use of cleanerfish has shown an effective, non-medical alternative to use of drugs. The involved industry partners Marine Harvest Labrus (MHL) and Villa Organic (VO), see this environmental-friendly method a s the primary solution to combat sea lice. However, the sustainable supply of wild caught wrasse will most probably not meet local demands in the future. It is therefore of great importance that a commercial, large scale production of cleanerfish is buil t up. Institute of Marine Research (IMR) has, in co-operation with VO, developed a basic protocol for production of the Ballan wrasse (Labrus bergylta), a large and efficient cleanerfish, also during winter time. MHL started commercial production of this species in spring 2009. An optimal broodstock diet is necessary for production of viable eggs and larvae, but no nutritional studies of broodfish have yet been conducted. Also, knowledge on nutrient requirement for offspring is lacking, and little is know n about temperature optima for the different stages. The present project is a collaboration between MHL, VO, IMR, NIFES and NOFIMA Ingrediens. The project will establish knowledge needed for formulation of palatable and nutritionally balanced diets at dif ferent life stages, incl. for broodfish, and determine optimal rearing temperatures and light conditions. The project will also include studies on technical quality of feed, as well as optimized timing of weaning. Furthermore, the practical use of farmed ballan in salmon cages has to be further studies, both with respect to serving as a cleaner fish, but also considering the health and welfare of this new reared species.