This study demonstrated that the dietary compositions of each of three abundant reefassociated labrid species in temperate Western Australia differed significantly with latitude and changed with increasing body size and almost invariably differed among species when those species co-occurred. These results were derived from comparisons and multivariate analyses of volumetric dietary data, obtained from the foregut contents of Coris auricularis, Notolabrus parilus and Ophthalmolepis lineolatus from the Jurien Bay Marine Park (JBMP) and waters off Perth, 250 km to the south. Latitudinal differences in the dietary compositions of each species in exposed reefs reflected large crustaceans, bivalves, echinoids and/or annelids typically contributing more to the diet in waters off Perth than in the JBMP, whereas the reverse was true for gastropods and small crustaceans. The diet of each species exhibited similar, but not identical, quantitative changes with increasing body size, with the contributions of small crustaceans declining and those of large crustaceans and echinoids increasing, while that of gastropods underwent little change. Within the JBMP, the dietary compositions of both C. auricularis and N. parilus were similar in exposed and sheltered reefs and the same was true for N. parilus in the latter reefs and interspersed areas of seagrass. The latter similarity in the diets of N. parilus demonstrated that, in both of those divergent habitat types, this species forages on prey living in or on the sand covering and around reefs or on seagrass. Although the main dietary components of each species were the same, i.e. gastropods, small crustaceans (mainly amphipods and isopods), large crustaceans (particularly penaeids and brachyuran crabs) and echinoids, their contributions varied among those species, which accounts for the significant interspecific differences in diet. Coris auricularis had the most distinct diet, due mainly to an ingestion of greater volumes of small crustaceans, e.g. amphipods and isopods, and smaller volumes of large crustaceans, e.g. brachyuran crabs, which was associated with a relatively narrower mouth and smaller teeth and the absence of prominent canines at the rear of the jaw. The above intra-and interspecific differences in dietary composition would reduce, on the lower west coast of Australia, the potential for competition for food among and within these three abundant labrids, which all belong to the Julidine clade.
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Corresponding author's name: Ian C PotterQuestion 1: If the fishes have been collected as part of faunal surveys, have the fishes, where feasible, been killed rapidly or returned to the wild after being held in aqua...
