The surf clam Donax (Plebidonax) deltoides (Lamarck, 1818), commonly known as the pipi, is found on sandy coastal beaches in south eastern Australia from southern Queensland to South Australia. Most populations world-wide are harvested by hand or with a shovel (Castilla and Defeo 2001). Species of Donacidae support recreational and commercial fisheries in Europe, Asia, Australia and the Americas (McLachlan et al., 1996).

The stock structure of pipi populations in Australia is not well known. Nevertheless, high genetic variation between populations on either side of Bass Strait suggests at least two biological stocks, with the East Australian Current and South Australian Current acting as key drivers of gene flow on the east and south coasts of Australia, respectively (Ferguson 2010, 2013).

This was supported by a study of Pipi from Fraser Island, Queensland, to southern New South Wales, suggesting a single biological stock with genetic mixing driven by ocean currents associated with the East Australian Current; however, the timescale over which patterns in genetic variation may have occurred is unknown (Ferguson 2010, 2013).

There is still too much uncertainty around the biological stock delineation of Pipi to determine stock status at the biological stock level. Hence, status is reported at the jurisdictional level for South Australia, Victoria and New South Wales (Sloan 2005).