Title: Optimization of blue mussel (<i>Mytilus edulis)</i>seed culture using recirculation aquaculture systems
Abstract: By introducing recirculation aquaculture systems (RAS) in the nursery phase of the blue mussel (Mytilus edulis) (17–18 mm), we aimed at a similar growth and survival and a similar water quality compared to the commonly used flow-through systems (FTS). To calculate water flow and size of the biofilter, a series of experiments were done to determine clearance rate (9.26 mL min−1), pseudo faeces threshold (60 000 cells Pavlova lutheri mL−1), nitrogen production (0.00065 mg TAN h−1 ind−1 and 1.6 × 10−5 mg NO2–N h−1 ind−1) and oxygen consumption (0.03 ± 0.01 mg O2 h−1 ind−1). RAS showed no significant differences in water quality (0.06 mg TAN L−1; 7.7 mg O2 L−1) and growth performance of mussel seed specific growth rate (SGR = 5% day−1) after the experimental period of 4 weeks compared with FTS. The low water refreshment, 10% per day, as well as the constant chlorophyll concentrations (9.76 ± 1.06 μg L−1), suggests the potential of RAS as culture system for mussel seed.