Behaviour, recruitment and dispersal of coral reef fish larvae: Insight into the larval life-stage

Despite the importance of larvae to the ecology of reef fishes, the ecology of the larval-stage itself is still relatively poorly understood because of the difficulty of tracking and observing very small fishes in the oceans' waters. Advances in the last few years have increased our understanding of the ecology of reef fish larvae, with a focus on the dispersal of larvae and connectivity between benthic adult populations. The goal of this dissertation is to gain insight into the life history of larval reef fishes. I have used a variety of techniques to investigate the biology and ecology of these animals as it pertains to their dispersal and recruitment to reef populations. I used recruitment monitoring surveys to investigate the occurrence of synchrony (or coherence) in recruitment (Chapter 2). I measured the spatial scale of recruitment coherence to infer larval patch size in the pelagic environment. I used an otolith microchemical assay to determine if larvae recruiting in coherent pulses experienced similar environments during their larval lives, inferring that larval patches were coherent throughout larval development and may have originated from similar source populations (Chapter 3). I used a different otolith microchemistry assay to directly measure the dispersal of larvae between reefs (Chapter 4). I measured the swimming performances of larvae of Caribbean reef fish species and used a specially designed swimming flume to examine the contribution of swimming and drifting to the displacement of larvae in a simulated pelagic environment (Chapters 5 and 6). I discuss the results of these studies in the context of the factors that likely cause variation in dispersal and recruitment. Finally, I suggest how to focus future research on the ecology of reef fish larvae.