Duchy Oyster Farm Update

Over the last two years the Duchy Oyster Farm has farmed the non-native Pacific oyster on the beds of the Helford. Pacific oysters were introduced to the UK under licence in the 1970s and introduced to the Helford and Percuil rivers in 1974 in collaboration with the Ministry of Agriculture and Fisheries. Pacific oysters are classed as a “non-susceptible” species, which means that they do not carry and are immune to the diseases and risks, which affect native species. In light of increasing sea temperatures, there has been growing concern that Pacific oysters will continue to spawn in UK waters in increasing numbers. The Duchy of Cornwall is now one of the first UK operators to adopt the cultivation of non-spawning triploid Pacific oysters on a large scale, therefore preventing any spread of the non-native species. The Duchy Oyster Farm has additionally spent time relaying native oysters onto the Helford beds, and if growth and results are as hoped, 2008 will be the first year that real Helford native oysters once again will be able to be sold to the country’s leading restaurants and hotels – albeit in a limited number!

Further plans of the Duchy Oyster Farm include a proposed demarcation zone for cage cultivation and fishermen’s store pots. Cages act to hold bags of oysters that are deployed sub-tidally. The proposed demarcation zone lies between Bosahan Point and The Voose. This is an area that has traditionally been used by local fishermen for their store-pots. The proposed zone is intended to accommodate oyster cages as well as the fishermen’s store-pots. The Duchy Oyster Farm for this purpose has liased with David Muirhead, as chairman of the Cadgwith Helford and District Fishermen’s Society, in order to get feedback from the local fishermen. The Oyster Farm will additionally liaise with individual fishing boats, and has undergone a voluntary consultation with users of the river. It will still be possible for boats to navigate within the zone, and for it to be accessed by all other river users at all time. By demarcating the area with navigation markers and on charts, the Duchy Oyster Farm hopes to be able to use smaller pick-up buoys which can be camouflaged in a dark grey or green colour as opposed to having to use large fluorescent marker buoys, designed primarily to be seen by river-users by way of their size and colour. The ultimate objective is to do away with surface markers altogether. With this in mind, the Duchy Oyster Farm are actively researching options such as the use of GPS and divers to locate and help retrieve cages as well as techniques and hardware for sub-surface marker and recovery systems, thereby reducing the visual impact on the river. It is hoped that this demarcation will help with safety and navigation within the Helford River.

Ben Wright & Rhiannon Pipkin

Extract from HVMCA newsletter No.37 Autumn 2008