Marine species possess dispersive stages that interconnect subpopulations,
which may inhabit ‘source’ and ‘sink’ habitats, where
reproduction and emigration either exceed or fall short of mortality and
immigration, respectively. Postlarval supply, juvenile density and adult
abundance of the Caribbean spiny lobster,
Panulirus argus, were measured at four widely separated
sites spanning >100 km in Exuma Sound, Bahamas. Adult abundance was lowest
at a site with the highest postlarval supply and little nursery habitat;
hence, it was tentatively classified as a sink. Circulation in Exuma Sound is
dominated by large-scale gyres which apparently concentrate and advect
postlarvae toward the nominal sink. The remaining three sites, including one
marine reserve, had higher adult abundances despite lower postlarval supply,
and are therefore tentatively classified as sources. Postlarval supply is
probably decoupled from adult abundance by physical transport. Adult abundance
is likely decoupled from postlarval supply by the effects of varying habitat
quality upon postlarval and juvenile survival, as indicated by non-significant
differences among sites in juvenile density. It appears that some sites with
suitable settlement and nursery habitat are sources of spawning stock for
Panulirus argus, whereas others with poor habitat are
sinks despite sufficient postlarval influx.
PREDICTABILITY OF REEF FISH RECRUITMENT IN A HIGHLY VARIABLE NURSERY HABITAT
