The biodiversity and physiological benefits of restoring Ostrea edulis reef habitat

A consortium of university researchers is developing a research proposal to investigate the potential of protected broodstock reefs of native oysters (Ostrea edulis) as a tool for enhancing marine biodiversity and fisheries across the UK. This 5 year programme of research will pursue 4 objectives at a range of sites including Loch Ryan, the Menai Strait, Strangford Lough and the Solent.

Native oyster populations have declined significantly in abundance and distribution around the UK since the 1800s mainly as a result of over-exploitation and lack of effective management.  Re-stocking of oysters as spat or part grown oysters was a regular occurrence from 1800 onwards for beds in the south of England from beds in the north but in the 1870s concerns over the stocks were so serious that imports began from France, Holland and USA with associated risk of introduction of disease and shellfish pests. The continual put and take fishery management of oyster individuals and dredging has not allowed the native oyster to live in its natural state for over a hundred years. However, the preferred settlement site of a native oyster is on a live oyster and this implies that there may be benefits of oyster assemblages. 

This project will compare the community biodiversity, oyster physiology and fecundity associated with individual native oysters and those occurring naturally in clumps or on simulated reefs.

The economic value of ecosystem services is much less understood for marine systems than for terrestrial ecosystems. This project will help expand this knowledge by estimating values for likely changes in ecosystem services due to the establishment of oyster reefs.

Specifically, this project will estimate the indirect benefits, the non-use value, the potential demand from tourism and the direct value for commercial production of O. edulis due to the establishment of oyster reefs.

The disease bonamiasis has had drastic reductions in O. edulis populations in France and is now becoming a real concern in the UK with outbreaks in 2006 recorded in Wales and Scotland raising important questions relating to the impacts of environmental change, acting via stress mechanisms in the host species, on the spread of this disease and also on the incidence of epizootic outbreaks. 

Thus this project will also examine the physiological robustness, bonamia-resistance and genetic diversity of existing geographically diverse UK populations.

The decline and threats to native oyster populations mean that the native oyster is a UK Biodiversity Action Plan Priority Species and the action plan has targets to maintain and expand the existing abundance and distribution around the UK.

The Consortium will produce recommendations to support the restoration of native oysters and their habitat throughout the UK.