Understanding how the dispersal of larval marine fish works is critical in managing a network of marine protected areas, and a study published in a recent issue of the Proceedings of the National Academy of Sciences has provided the first empirical evidence of how this dispersal works.
Serge Planes, Geoffrey Jones and Simon Thorrold used DNA parentage analysis (by utilizing 16 polymorphic microsatellite DNA markers) to study how the orange clownfish (Amphiprion percula) dispersed within a proposed network of marine reserves in Kimbe Bay, Papua New Guinea.
Female clownfish spawn benthic eggs that hatch after about seven days of parental care. Larvae then drift for about 11 days before settling into an anemone, where they will remain for the rest of their lives.
After analyzing 506 potential clownfish parents from Kimbe Island and 400 newly settled juveniles from all around Kimbe Bay, the authors identified 122 juveniles ash having parents from Kimbe Island.
Of these 122 juveniles, 42% remained on Kimbe Island itself, with the remainder being found in locations around Kimbe Bay up to 35 km away.
The latter were not merely wayward individuals, comprising up to 10% of the populations they joined.
The authors conclude, This information is vital to the spatial management of marine species, particularly for evaluating the optimal size and spacing of reserves in networks.
The dispersal pattern that we found supports the contention that individual marine reserves can be of a size that offers protection of resident populations and spaced within a network to allow for significant exchange of dispersers among reserves.
For more information, see the paper: Planes, S, GP Jones and SR Thorrold (2009) Larval dispersal connects fish populations in a network of marine protected areas. Proceedings of the National Academy of Sciences 106, pp. 5693"5697.