Spatial and temporal dynamics of temperate Australian rockpool ichthyofaunas

Abstract

Spatial and temporal variation, and factors influencing the structure of intertidal rockpool fish assemblages were quantitatively investigated at three large rocky headlands in south-eastern New South Wales, Australia. A total of 5244 fish from 46 species, mainly permanent intertidal residents from the families Clinidae, Blenniidae, Tripterygiidae, Gobiidae, Gobiesocidae and Girellidae, was caught in the rockpools. Numbers of species and individuals and dominance patterns of species showed significant variability within locations, possibly in response to variations in rockpool tidal height and volume, or environmental variables, such as temperature and dissolved oxygen. Species composition also differed among locations, probably as a result of availability of different habitats at each location, which may be preferred by different species. Fish assemblage structure was stable and persistent through time, presumably because rockpools are colonized only by species suitably adapted to the dynamic intertidal environment. Temporal variability in the abundance of some common species occurred during summer and autumn, mainly owing to recruitment of resident fishes. Directions for future research are given, which may contribute to an understanding of the processes that underpin these patterns.