CS12 Coral Reefs
Date: Wednesday, June 12, 2002
Time: 4:45:00 PM
Location: Colwood
 
MaySE, UCLA, Los Angeles, USA, smay@ucla.edu
 
Fish and Crinoid Distributions are Influenced by Water Movement on a Coral Reef
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Ecologists are often concerned with mechanisms that cause spatial patterns in organism distributions. On coral reefs, water energy regimes have been implicated in distributions of corals, but have not been definitively linked to distributions of other more mobile organisms. To relate local scale oceanography to planktivorous fish and crinoid distributions and feeding, I measured flow fields and organisms distributions around 2 small islands (250m2 and 1800m2) in Palau Micronesia. Feeding by diurnal planktivorous fish (Amblyglyphidodon curacao) shows a highly significant positive relationship (p < 0.001) to current velocity regardless of tidal stage. Diurnal and nocturnal (Myripristis sp.) planktivorous fish distributions were significantly correlated with one another and coincided with impinging water flow at the islands. Nocturnal crinoids (a benthic filter feeder) were qualitatively distributed with site speed and no other environmental variable. Transplanting crinoids from higher to lower average water speed sites resulted in significant (p< 0.05) movements of the crinoids away from transplanted sites as compared with controls. Thus this study tightly correlates movements and distributions of organisms on coral reefs with water movement characteristics.