This project has been a successful collaboration between pearl farmers, academic scientists and museum taxonomists and has given the scientific community greater access to remote regions of Australia, facilitating the description of new species to science. It has highlighted the inherent variability and abundant biodiversity of shallow water benthic communities in northern Australia. The study employed an exhaustively designed sampling regime incorporating three spatial scales (10’s of metres, 1-5 km, >100’s km) and random sampling through time. A multi-control sampling strategy was undertaken to give an estimate of the natural variability of the region and to test for benthic impacts at three pearl farms that have been in use for up to 40 years. Multiple lines of evidence all conclude that the variability in benthic conditions at the farms is within the bounds of the natural variability at the reference locations. The main mechanisms that influence the impact of shellfish aquaculture are considered to be; the farming method, the density of the cultivated shellfish (or stocking rate), the water depth of the farm area and the hydrographical conditions in the area (Danovaro et al 2004). All these factors favor the northern Australian cultured pearl industry and would contribute to the lack of a benthic footprint documented by this study.
The conclusion drawn from these studies is that current pearl oyster culture techniques in northern Australia have no detectable effect on the sediments of the lease sites. As ongoing or frequent benthic monitoring is logistically challenging and expensive in context of northern Australian pearl farms and cannot be expected to observe anything but natural variability it would not be a wise use of scarce industry funding to include benthic monitoring protocols in the standard EMS for this industry. If major changes to farming practice creates uncertainty in the future on this issue, or political climate requires revalidation of these findings, a further study such as this, conducted as corporate industry research, such as this project, could again test the issue
