HATCHING TIMES, LARVAL DURATION, SETTLEMENT AND LARVAL GROWTH OF PLAICE (<i>PLEURONECTES PLATESSA</i> (L.)) IN GALWAY BAY DETERMINED USING OTOLITH MICROSTRUCTURE

Abstract

The otolith microstructure of juvenile plaice from two beaches in Galway Bay on the Irish west coast, Ballyloughaun and Silverstrand, was examined. Sampling was carried out monthly in the spring of 2003. The hatch date, larval duration, settlement date and larval growth rates were determined for 85 fish. Hatching occurred from late January to late March. The mean larval duration was 33 days, and fish settling earlier in the year had a longer larval life on Silverstrand. Settlement occurred between early March and late April. Settlement pulses closely corresponded to hatching times, indicating that hatching/settlement cohorts could exist for plaice in Galway Bay. Larval growth was consistent between locations assessed. There was a positive relationship between larval growth and hatch date, and an inverse relationship was noted between larval growth and larval duration. Results from this study were compared to studies from other European areas, and a relationship between larval duration and temperature was noted, with fish from cooler areas in Europe having longer larval durations. This is the first study of its kind on the west coast of Ireland and the first study within eastern Atlantic waters to focus on the early life history of plaice.