Although most of Poole Harbour is about 12" deep, being muddy it is full of nutrients and loved by these bivalves. All cockles and clams are purified in tanks which pass the water over UV lights, killing any harmful bacteria. This process has to be for a minimum of forty two hours - the result is a safe, grit-free gastronomic treat. The Cockles and clams are collected by the environmentally responsible hand raking method. All orders are sent with purification certificates.