Otolith microstructure of a hatchery reared European hake (Merluccius merluccius)

European hake (Merluccius merluccius) were reared from eggs up to 245 days of age in temperature and salinity controlled stable conditions. The lapillus and sagitta of one of these fish were examined for microstructural features. The age derived from the increments support the daily nature of the hake sagittal increments starting the formation at day 8, probably related to the start of exogenous feeding. The lapillus shows a later increment formation. The sagitta otolith increments show rhythmical groupings and banding that are similar to wild fish. The accessory growth centres appear to be related to pectoral fin development and demersal habitat. The growth rates obtained are discussed.