Genetic identification of sharks traded and consumed in Australia

Shark species worldwide are under threat mainly from over harvesting either as by catch or in targeted fisheries. In Australia shark flesh is mostly sold under the name 'flake' and distributed around the country. The Australian Fish Names Standard state that sharks sold under the name flake must be either Australian Gummy shark (Mustelus antarcticus) or New Zealand rig (Mustelus lenticulatus), however labelling is not mandatory. In this study we hypothesized that many sharks sold as flake did not qualify under the naming standard, and that threatened species were being traded. We used DNA barcoding to identify species from 91 samples obtained from 29 seafood retailers across the country. To determine species composition we used Sanger sequencing of two genes, the Cytochrome Oxidase subunit one gene (CO1) and the 12S mitochondrial RNA gene (12S). We identified 67 cases (78.8%) of misllabeling and 16 cases (35.6%) of threatened species being traded, including the Scalloped Hammerhead (Sphryna lewini) and School Shark (Galeorhinus galeus). Our results showed that mislabelling of shark flesh is occurring in Australia, and that threatened species make up a sizeable portion of the species sold. These data demonstrate the need to improve labelling standards to work towards minimizing our impact on threatened shark species -- abstract