Gemfish (Rexea solandri) are a bottom dwelling fish which inhabitat deep water off the New South Wales, Victoria, South Australia and Tasmanian coasts. Generally found in large schools at depths of 100 - 800 metres. Gemfish inhabit oceanic continental shelf and upper slope waters, and are distributed throughout southern Australian and New Zealand waters. The eastern Australian population is genetically different to the western Australian population, and different to the two populations of gemfish found in New Zealand waters (Wilson et al. 2010).

There are considered to be two biologically distinct stocks of Gemfish in Australia—an eastern and a western biological stock—separated by a boundary at the western end of Bass Strait1. Studies suggest that there are no genetic differences between Gemfish in eastern Australia and New Zealand. For the purposes of management and assessment, the eastern Australian population is treated as a single biological stock, independent of the New Zealand population (Colgan and Paxton 1997).

Eastern gemfish are caught at depths from 100 to 600 metres (approx. 50 to 300 fathoms) from northern New South Wales / southern Queensland to southern Tasmania. The majority of the catch is taken north of 40°S latitude. Off New South Wales, the 100 m-depth contour generally lies between 5 and 10 nautical miles (n.m.) from the coastline; however, in some areas (off Kurnell, Jervis Bay and Montague Island) the 100 m depth contour can be found 2 to 3 n.m. from the coast (Wilson et al. 2010).