Blue Swimmer Crabs Portunus pelagius, Mud Crabs Scylla serrata, Soldier Crabs, Spiny Lobsters or Sea-crayfish Jasus verreauxi, Eastern King Prawn Penaeus plebejus, Eastern School Prawn Metapenaeus maclyeayi and rock barnacles such as the large 'purple plated' Austrobalanus imperator are common in Sydney Harbour. The only crustaceans reported by the colonists to have been eaten were crayfish, which were caught in Port Jackson with small hoop nets. There is no mention at all of prawns, crabs or barnacles being caught or eaten, though the name for crabs, Ke-ra, was recorded.

Archaeological excavations have recovered only small amounts of crab and crayfish remains. The fragility of the exoskeletons, which do not survive well in archaeological deposits, probably explains why only small amounts are found. Barnacles occur in middens, but they may not have been collected for food as they often attached themselves to other shellfish that were eaten.