The wild blood cockle, locally known as bimbala (Tegillarca granosa), is a species of the Arcidae family recognized by its distinct bivalve ‘lip’. Its shell is thick and solid with ovate inflated shape. It grows only in special conditions in tidal bays and estuaries at one to two meters water depth burrowed into the sand. Adult size is about 5 to 6 cm long and 4 to 5 cm wide. It is very slow growing.
The bimbala is a traditional Indigenous Australian food as evidenced by the amount of shells found in ‘middens’. Shell middens are places where the debris from eating shellfish and other food-remains, charcoal from campfires, and tools made from stone or shell are collected. Shell middens are found throughout Australia, usually close to the coast, but they can also be around inland lakes, swamps and riverbanks. Shell middens can be hundreds or thousands of years old and as such have an important scientific role telling us about Indigenous people activities in the past.
Nutritionally, bimbala are very high in iron due to the hemoglobin liquid they contain. When raw, they have a vibrant red/burgundy color; when cooked they turn a darker red/brown. They are available all year round, rather than being seasonal. As they filter bacteria, they also have an important role to play in fragile marine ecosystems.
There have been huge losses of bimbala due to overfishing (they are a popular food in Asia), wave action from power boats, and coastal erosion caused by habitat destruction and development/human coastal activities. It is therefore essential to protect them and ensure controlled harvesting.
Indigenous people of the Budawang (NSW South Coast) used to put the bimbala shells on hot coals/ashes to cook. They steam open in their own juice, and get eaten out of the shell, after which the shell remains are discarded in shell middens.