ASPECTS OF THE REPRODUCTIVE-BIOLOGY OF THE BASS, DICENTRARCHUS-LABRAX L .2. FECUNDITY AND PATTERN OF OOCYTE DEVELOPMENT

The European bass, Dicentrarchus labrax L., in common with most temperate marine teleosts, exhibits a distinct seasonal reproductive cycle. Its reproductive strategy is characterized by a high absolute fecundity (2‐25 × 105), both absolute and relative fecundity increasing with size and age. The cyclic pattern of oocyte development has been determined by histology and from oocyte size frequency analysis. Results show that the bass exhibits group‐synchronous oocyte development and is a ‘fractional spawner’, i.e. it spawns a number (3–4) of discrete clutches in quick succession, successive clutches containing fewer oocytes. All oocytes which are recruited into the secondary growth phase (> 110 μrn) are either spawned that season or become atretic, i.e. no secondary oocytes are held over for the subsequent reproductive season. Copyright © 1990, Wiley Blackwell. All rights reserved