Hatchery broodstock conditioning of the blue mussel Mytilus edulis (Linnaeus 1758): Part I. Impact of different micro-algae mixtures on broodstock performance

摘要

Blue mussel () broodstock collected from the Irish Sea during wintertime (November) was conditioned with three different microalgae diets. Positive flagellates (PF) treatment consisted of , (T-Iso), and (1:1:1). Positive diatoms (PD) treatment consisted of , , and (1:1:1). Broodstock animals in the PF and PD treatments were fed a total of 2.4 × 10 algae cells per day. Animals in the negative flagellates (NF) treatment received only 1/8th of the total amount of algae of the PF diet. The conditioning diets had an impact on spawning success and broodstock fecundity but not on hatching rate, which was similar in all three groups. The best results were obtained with the PD diet where 84% of the conditioned animals spawned and females released 5.0 × 10 eggs on average. Animals belonging to the PF and NF treatments released, on average, only 3.6 × 10 and 1.6 × 10 eggs, respectively. Although the amounts of algae provided to the broodstock animals had no effect on the hatching rate, the D-larvae resulting from the NF treatment were smaller in size than the larvae from the other treatments. Biochemical analysis of the different broodstock groups at the end of the experiment revealed higher carbohydrate levels in group NF than in PF and PD, supporting the theory that gametogenesis is mainly supported by the energy from the glycogen reserves. As far as we are aware this is the first study describing hatchery broodstock conditioning of blue mussels under fully controlled conditions.