The relationship between temperature and the size and age of larvae and peri‐metamorphic stages of Pleuronectes flesus

Laboratory observations of live animals were used to describe the developmental sequence of the flounder Pleuronectes flesus. Developmental state was related to age and total length (LT) from hatching, through metamorphosis, to the juvenile form. By following animals at 7, 11 and 15° C it was found that, whilst the LT at metamorphosis was the same for all the temperature regimes and was not temperature‐dependant, the time taken to reach this stage was related to rearing temperature. It was also observed that animals could be induced to metamorphose by transfer to reduced salinity but only if they were close to the critical length for metamorphosis.