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Estuaries are critical habitats subject to a range of stressors requiring effective management. Microbes are gaining recognition as effective environmental indicators, however, the response of host associated communities to stressors remains poorly understood. We examined microbial communities from seawater, sediments and the estuarine fish Pelates sexlineatus, in Australia's largest urbanised estuary, and hypothesised that anthropogenic contamination would be reflected in the microbiology of these sample types. The human faecal markers Lachno3 and HF183 were not detected, indicating negligible influence of sewage, but a gradient in copy numbers of the class 1 integron (intI-1), which is often used as a marker for anthropogenic contamination, was observed in sediments and positively correlated with metal concentrations. While seawater communities were not strongly driven by metal contamination, shifts in the diversity and composition of the fish gut microbiome were observed, with statistical links to levels of metal contamination (F2, 21 = 1.536, p

The ability of animals to act in a bioremediative capacity is not widely known. Animals are rarely considered for bioremediation initiatives due largely to ethical or human health concerns. Nonetheless, specific examples in the literature reveal that many aquatic species, including species employed in aquaculture, are effective remediators of metals, microbial contaminants, hydrocarbons, nutrients and persistent organic pollutants. We introduce zoological equivalents of the definitions used in the phytoremediation literature (zooextraction, zootransformation, zoostabilisation and animal hyperaccumulation), to serve as useful benchmarks in the evaluation of candidate animal species for zooremediation initiatives. Further, we present a case study assessing the deployment of pearl oysters to remove metals and nutrients from aquatic ecosystems.