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Shellfish farming with a long tradition

Did the aboriginal people of North America cultivate shellfish in aquaculture? The Canadian research team led by archaeologist Dana Lepofsky have found that the indigenous people of North America farmed shellfish on the Canadian Pacific coast more than 1000 years ago.

Lepofsky has presented the latest findings of her research on the clam gardens of Quadra Island in the 'American Antiquity' journal. These water gardens are further evidence that refutes the standard image of the native population as hunters and gatherers. Not only did American natives cultivate fruit trees, root vegetables and berries on land, but they also developed a means of using the sea for agricultural production, at a very early stage.

Native American oral traditions made reference to agricultural activity, but this was ignored by white scientists for 150 years. However, this has now changed. Excavations on Quadra Island have produced evidence that aboriginal shellfish farmers had a profound knowledge of their craft. These early aquafarmers built stone barriers on the beaches to prevent seawater from flowing back into the ocean. Reared in artificial water tanks, the shellfish multiplied greatly. Terraces were created in the tidal zone that provided ideal, protected conditions for the colonisation and growth of many different types of shellfish. They formed the ideal habitat for butter clams, for example.

Research that is not only of interest to modern aquaculture

The Lepofsky team also hopes to discover more about aquaculture by making a precise analysis of these early shell banks. For example, they are interested to know if the ancient shell banks can offer any help in dealing with the acidification of the ocean regions.

In their three-year pilot study, the scientists were able to show that around four times as many clams as in natural shell banks and twice as many carpet shells could be grown in these early shell gardens. The researchers hope that this thousand-year-old shellfish cultivation might reveal something that will be of benefit to our modern aquaculture.