The effect of seawater flow and temperature on metamorphosis and postlarval development in great scallop

R. Robert, L. Nicholas-2000
Aquaculture International, 8 (6): 513-530

Abstract:
Variations in growth and survival of hatchery-reared post-metamorphic juveniles of great scallop Pecten maximus prompted an examination of settlement and postlarval development. The effects of seawater flow and temperature on great scallop metamorphosis and postlarvae were studied over a 4–5 week period. In all experiments, and regardless of environmental conditions, great scallop metamorphosed after a 2–3 week period with values of 35 to 70%. Subsequently, spat numbers increased slightly. Spat mortality generally occurred from the third week onward and reached levels as high as 30% by the fifth week under standard conditions. At 20 °C, however, 60% mortality levels were recorded. Differences in spat growth rate, ranging from 37 to 45 mm day^−1, were noticed at different seawater flow rates but no clear tendency could be discerned. Temperature affected spat growth with an increase in size from 24 mm day^−1 at 15 °C to 35 mm day^−1 at 18 °C. Conversely, growth was suppressed at 20 °C (14 mm day^−1). For optimal metamorphosis and postlarval development in great scallop, a seawater flow of 4.3 L h^−1 per sieve and a temperature of 15 °C are recommended.

(Laboratoire de Physiologie des Invertébrés Marins, Ifremer, Station Expérimentale d‘Argenton, Presqu‘île du Vivier, 29840 Landunvez, France , E-mail: rrobert@ifremer.fr)

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