| Harvesting Technology |
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We have been harvesting clams, oysters, cockles and mussels in Poole Harbour since 1988. Our grounds dry out very rarely, so we can not use conventional tractor based farming techniques. On the other hand, our water is shallow and the species that we harvest are fragile and need to be treated very gently. This means that we have had to develop unique and innovative harvesting techniques, which have had to evolve and improve as our production has increased. First we used a sort of underwater vacuum device, but this meant that the user had to stand in the water. We then adapted a boat to suck up clams through a 6-inch pipe directly in to the boat. This system worked well, but caused some shell damage. Eventually we realised that the way to go was a conveyor harvester that blows the shellfish out of the substrate using water jets. They are then gently transported into the boat via a stainless steel mesh belt. Our prototype was constructed of aluminium and glass fibre in a catamaran configuration. Once we knew what we needed, we had a steel craft constructed by a local boatyard and we have been using this boat very successfully since 1998. This boat has been dubbed 'the eco-harvester' as it is so gentle on the shellfish and the seabed. On well-stocked ground it will catch 5 tons per hour and it is perfect for us, as it will harvest all the species that we farm using the same gear. Following the success of our harvester, we have had enquiries from shellfish farmers who want a similar vessel. However, we are always careful to explain that this system is only suitable for fishing in water no deeper than 5 metres because of the length of conveyor needed. We have acted as consultants on two boats in Canada, two in Ireland and two in the UK. The boats can be seen in our web Picture Gallery. |
Harvesting Technology
