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Many marine animals have a biphasic life cycle in which demersal adults spawn pelagic larvae with high dispersal potential. An understanding of the spatial and temporal patterns of larval dispersal is critical for describing connectivity and local retention. Existing tools in oceanography, genetics, and ecology can each reveal only part of the overall pattern of larval dispersal. We combined insights from a coupled physical-biological model, parentage analyses, and field surveys to span larval dispersal pathways, endpoints, and recruitment of the convict surgeonfish Acanthurus triostegus . Our primary study region was the windward coast of O‘ahu, Hawai‘i. A high abundance of juvenile A . triostegus occurred along the windward coast, with the highest abundance inside Kāne‘ohe Bay. The output from our numerical model showed that larval release location accounted for most of the variation in simulated settlement. Seasonal variation in settlement probability was apparent, and patterns observed in model simulations aligned with in situ observations of recruitment. The bay acted as a partial retention zone, with larvae that were released within or entering the bay having a much higher probability of settlement. Genetic parentage analyses aligned with larval transport modeling results, indicating self-recruitment of A . triostegus within the bay as well as recruitment into the bay from sites outside. We conclude that Kāne‘ohe Bay retains reef fish larvae and promotes settlement based on concordant results from numerical models, parentage analyses, and field observations. Such interdisciplinary approaches provide details of larval dispersal and recruitment heretofore only partially revealed.
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Quantifying dispersal variability among nearshore marine populations
Abstract Dispersal drives diverse processes from population persistence to community dynamics. However, the amount of temporal variation in dispersal and its consequences for metapopulation dynamics is largely unknown for organisms with environmentally driven dispersal (e.g., many marine larvae, arthropods and plant seeds). Here, we used genetic parentage analysis to detect larval dispersal events in a common coral reef fish,Amphiprion clarkii, along 30 km of coastline consisting of 19 reef patches in Ormoc Bay, Leyte, Philippines. We quantified variation in the dispersal kernel across seven years (2012–2018) and monsoon seasons with 71 parentage assignments from 791 recruits and 1,729 adults. Connectivity patterns differed significantly among years and seasons in the scale and shape but not in the direction of dispersal. This interannual variation in dispersal kernels introduced positive temporal covariance among dispersal routes that theory predicts is likely to reduce stochastic metapopulation growth rates below the growth rates expected from only a single or a time‐averaged connectivity estimate. The extent of variation in mean dispersal distance observed here among years is comparable in magnitude to the differences across reef fish species. Considering dispersal variation will be an important avenue for further metapopulation and metacommunity research across diverse taxa.
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- PAR ID:
- 10452173
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Molecular Ecology
- Volume:
- 30
- Issue:
- 10
- ISSN:
- 0962-1083
- Page Range / eLocation ID:
- p. 2366-2377
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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