THE EFFECTS OF GEOGRAPHY AND HURRICANE DISTURBANCE ON A TROPICAL PREDATOR-PREY INTERACTION

Temperate-tropical predation comparisons require estimates of the variability of predation intensity within those climatic zones. Latitudinal comparisons are possible only if predation is consistent within localized areas. This study investigated two aspects of predation intensity experienced by the Caribbean ophiuroid Ophiothrix oerstedi Lutken within and among back reef sites in Jamaica, St. Croix, Barbados, and Belize. Predation potential, the propensity of predators to consume prey, was measured experimentally as the mortality of tethered ophiuroids. Predation pressure, the natural frequency of predator-prey encounters, was measured as the frequency of sublethal damage: the proportion of ophiuroids regenerating one or more arms. Daytime and nighttime predation potentials were clustered by site, not by season, year, or temporal relationship to hurricane events. Daytime predation potential was positively correlated with the abundance of predatory fishes (wrasses). Although the abundance of nocturnal predators did not vary significantly among sites, among-site differences in species composition partially explained the observed differences in nighttime predation potential. There were neither significant among-site differences, nor within-site temporal patterns, in the frequency of sublethal arm damage in 0. oerstedi populations. Strong hurricanes did not increase arm damage frequencies at Jamaica or St. Croix, implying that few injuries are caused by storms. The consistency of predation potential on 0. oerstedi within sites suggest that latitudinal comparisons will be possible with ophiuroids.