Temporal variability in patterns of association among fish species on coral patch reefs

Abstract

Data on the distribution of 25 common species of fish over 20 patch reefs located in a coral reef lagoon (Great Barrier Reef) were collected by 20 visual censuses over 10 yr. Associations among the 25 species were examined by cluster analysis. The overall pattern of association changed substantially from census to census. So too did the relationships among small subsets of the 25 species which were tightly associated at one or more censuses. The degree of association among groups of species was compared with that expected under a null model of non-interactive recruitment of fish to patch reefs. Species in many apparently closely associated small groups were less strongly associated than expected under the null model, suggesting that species react differently to the habitats offered by the patch reefs, or respond negatively to each other's presence. Results are discussed in the light of other information on the structure of these assemblages of fish.