Behavior constrains the dispersal of long-lived spiny lobster larvae

Abstract

Behavior such as ontogenetic vertical migration (OVM) limits the transport of marine larvae with short pelagic larval durations (PLDs), but its effect on the supposed long-distance disper- sal of larvae with long PLDs is unknown. We conducted laboratory tests of ontogenetic change in lar- val phototaxis and examined size-specific patterns of larval distribution in the plankton to character- ize OVM in the Caribbean spiny lobster Panulirus argus during its long (6 mo) PLD. We then used a coupled biophysical model to explore the consequences of OVM and hydrodynamics on larval P. argus dispersal in the Caribbean Sea. Larvae reared in the laboratory were positively phototatic for the first 2 mo and then avoided light thereafter, similar that seen in the planktonic distribution of same-sized larvae. Simulations of larval dispersal from 13 spawning sites in the Caribbean Sea pre- dicted that twice as many larvae would recruit to nurseries if they displayed OVM compared with passive dispersers. Larvae with OVM typically settled 1000 km away. OVM also produced an asymmetrical bimodal pattern of dispersal dominated by larvae that settled near their origin (~60%), but showed a second peak of larvae that dispersed over long distances (~20%). Hydrodynamics created subregional differ- ences in the potential for self-recruitment. Our findings suggest that (1) larval behavior constrains the dispersal of even long-lived larvae, particularly in tandem with retentive oceanographic environ- ments, and (2) larval sources of P. argus in the Caribbean Sea cannot be estimated from passive trans- port and surface circulation.