CHANGES IN OTOLITH MICROSTRUCTURE AT METAMORPHOSIS OF PLAICE, PLEURONECTES-PLATESSA L

Individually reared plaice were monitored by morphologically defined s tages until 10 d after metamorphosis. Otoliths (sagittae) were sampled prior to, at, and after metamorphosis. All but one individual had cir cular sagittae without secondary growth centres (accessory primordia) before metamorphosis. Four days after metamorphosis, all sagittae disp layed one or more accessory primordia. The numbers of accessory primor dia on the left and right sagittae were not significantly different. T hus, the use of accessory primordia in combination with ageing techniq ues to back-calculate time to and from metamorphosis of sampled juveni les is validated. (C) 1996 International Council for the Exploration o f the Sea