The ecology of soft sediment tidepool dwelling gobies (Pisces: Gobiidae) in Moreton Bay, Australia

Tide pools are challenging environments. They can experience rapid changes in temperature, salinity and pH yet are occupied by fishes and other organisms. While more attention has been given to community composition, zonation and competition of intertidal rockpool faunas, soft sediment tidepools are potentially important in terms of biodiversity and fisheries. Gobies, dominate the communities of both rock- and soft sediment pools by virtue of physiological and behavioural adaptations. In part their great diversity is potentially a function of the ability to cope with great adversity. The combination of physiological challenges and low resource diversity offers and useful natural laboratory for examining resource partitioning and speciation processes in extreme environments. Moreton Bay, Australia contains extensive areas of soft sediment shores on which pools commonly occur. The objectives of this thesis were to: 1) quantify the use of soft sediment tidepools by fishes and their associated meiofaunal prey, and 2) examine more closely how several gobiid species are able to coexist in such a homogenous environment. A twelve month survey of fishes in soft sediment tidepools was undertaken between January and December 2009 at three sites: Dunwich, Manly and Godwin Beach, in south-east Queensland, Australia. The gobies Favonigobius lentiginosus, Favonigobius exquisitus, Pseudogobius sp., whiting Sillago spp. and the blenny Omobranchus punctatus were the most abundant species. The mean density of fish was between 0.29 ± 0.13 and 5.04 ± 1.74 fish L-1. Abundance of fish was positively correlated with pool volume. Most fish caught were juveniles, suggesting that soft sediment pools act as nurseries for some species. To assess prey availability and therefore the potential role of soft sediment pools as foraging areas during low tide, I assayed the meiofaunal occupation of soft sediment tidepools at each of the three intertidal shores. Mean maximum meiofaunal abundances were found at Godwin Beach (1389.2 ± 158.2 individuals per 20 cm3) and abundances differed significantly among months. Nematodes and copepods were the most abundant taxa while all other taxa contributed t