Sustainable fish and shellfish farming

Task 3.4 Mussels endemic to low-temperature and clean waters of the Norwegian coasts have the potential to become important protein sources for pets, poultry, and aquaculture. Two mussel species are chosen for comparison: common mussel (Mytilus edulis) and Northern horse mussel (Modiolus modiolus). Broodstock will be collected from a commercial mussel farm outside Trondheim and held in 500L flow-through tanks in a temperature-controlled room at the Nofima Research Station in Sunndalsøra. The broodstock will be fed live algae (Isochrysis sp and Rhodomonas sp. and regularly monitored for gonadal development. Spawning will be induced by temperature shock. Eggs from different females will be pooled before the addition of sperm. Algae (Isochrysis sp. and Nannochloropsis sp.Rhodomonas) will be introduced 24 hours post-fertilization. After 48 hours, the larvae will be transferred to 25 l conical flow-through incubators with aeration, where they will be fed a combination of live algae strains supplied by AlgaVida (Dunaliella sp., Isochrysis sp, Phaeodactylum sp, Tetraselmis sp., Chaetoceros sp., Thalassiosira pseudodana). Different ratios of algae will be tested throughout the larval rearing and spat settlement stages. At the pediveliger stage, the larvae will be transferred to a substrate for settling. Attempts to use natural fibres and not plastic for settlement will be done. Settled larvae will be transferred to the facilities of AlgaVida for growing in a flow through system and a RAS system. During this phase, Nannochloropsis oceanis and Phaeodactylum tricornutum will also be tesed since those algaes will be used for industrial production of Omega-3-oil by AlgaVida and they will rinse the growth medium resirculation through mussel RAS. The biochemical composition of different food regimes and larvae will be analysed. Mussel samples will be fixated with Bouin’s solution for further histologyc interpretation of the mussels anatomy by experienced researchers in IRTA.