DAILY PERIODICITY AND TIMING OF THE SPAWNING OF SOLE, SOLEA-SOLEA (L), IN THE THAMES ESTUARY

Hourly sampling during five 24-h periods in the Thames estuary with a 2-m ring-net produced more than 14 000 live sole eggs. The development stages of these eggs were determined within 30 min of capture and the results used to determine the time of spawning. There was a single peak of spawning each evening which ranged from 1615 h to 0100 h on different days and at different locations. Tidal phase appeared not to be a cause of the variation in timing. © 1991 Conseil International pour l'Exploration de la Mer.