Growth and pelagic larval duration of presettlement and newly settled neon damselfish, Pomacentrus coelestis, at multiple spatial scales

摘要

Variation in planktonic larval duration (PLD) and growth of Pomacentrus coelestis was investigated on the southern Great Barrier Reef at multiple spatial scales. A tetracycline experiment, using presettlement fish, demonstrated that increments were formed daily. Variation in PLD was low between reef clusters (0%), reefs within clusters (0.4-8.5%) and sites within reefs (13.1%), but high among individuals within sites (86.5-91.5%); PLD ranged from 15 to 27 days. It was predicted that PLD would vary at greater spatial scales, but differences were low and a review of all studies on P. coelestis in tropical waters had a similar range of PLDs to our study. Contrary to a hypothesis that fish with slower growth would have longer PLDs, there was no significant relationship between mean presettlement increment width of otoliths and PLD for fish from the two reef clusters examined. There were, however, differences in presettlement growth rates between reef clusters (over 100 km apart) over the last 5-6 days of planktonic life. Warmer waters at the Swain Reefs (0.1-1°C) may have contributed to these differences in growth. Stochastic transport of larvae, habitat choice by presettlement fish in a reef mosaic, and variable conditions in the plankton may contribute to variation in PLD, presettlement growth and size-at-settlement in P. coelestis. We propose that prolonged periods of settlement choice may obscure simple relationships between PLD and size-at-settlement.