Abstract

Among marine taxa spiny lobsters lie at the extreme with respect to larval duration, which in some species can approach 2 years. Thus, their dispersal kernels theoretically span hundreds to thousands of kilometers unless the larvae possess behaviors, such as stage-specific differences in vertical migration, that when coupled with relatively persistent physical oceanographic features may constrain their transport. Attempts to understand the connectivity of Caribbean Spiny Lobster (Panulirus argus) populations have so far fallen short, due to methodological limitations and the absence of knowledge on larval and postlarval duration and behaviors. Our approach is to combine laboratory studies of larvae and mining of data on regional differences in adult population structure and dynamics with oceanographic modeling, then to test model predictions with empirical measures of larval supply. We successfully, and for the first time, reared P. argus from egg to juvenile and have determined not only the duration of the larval period but also stage-specific larval responses of larvae and postlarvae to light and chemical cues that may affect dispersal. Our experiments revealed distinct differences among larval stages in their response to light spectra and intensities indicative of different ocean depths. Those results are consistent with our observations of larval vertical distributions from plankton sampling. We also discovered that the strong-swimming postlarvae are attracted to coastal chemical cues far from shore, particularly cues emanating from red algae. These results are now being incorporated into a Lagrangian particle model linked with the Hybrid Coordinate Ocean Model (HYCOM) to generate predictions of connectivity among Caribbean regions, which we will evaluate relative to empirical estimates of postlarval supply measured at a network of Caribbean locations

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