Quantifying the status and success on restored native oyster Ostrea edulis beds in the Solent.

Project Rationale:

Globally, the restoration of ostreid bivalves is gaining momentum. In European waters the native oyster Ostrea edulis is the focus of extensive restoration efforts and in the Solent, the Blue Marine Foundation (BMF) have been leading efforts to restore native oysters since 2017. The Solent historically represented the UK’s largest oyster fishery, but has been in decline since the 1970s and generally has been closed to fishing since 2013. The Solent system represents a good model to understand how best to restore a habitat that no longer exists; insights that can be scaled to the wider Europe and beyond.

Thus far our work has compared the performance of small scale elevated culture of broodstock oysters in suspended cage culture in marinas with elevated reef culture on the sea bed1 and has explored the environmental controls of sex determination and gametogenesis in native oysters2-3. Research is also quantifying the services offered by oysters for nutrient regulation and microplastic removal from the environment.

This studentship will develop a large-scale restoration strategy for relayed oysters in the River Hamble (Solent) and in Newtown Harbour on the Isle of Wight, and will then quantify the success of that strategy through monitoring.

Methodology:

The project will have address the following objectives with associated methodology:

a) assess the performance of relaid oysters in comparison with environmental conditions in both locations, and with the performance of oysters from other UK populations. This will employ environmental sampling, and laboratory assessments of metabolic rate (proxy: respiration rate), bulk, biochemical composition, and indices of cell function.
b) assess the reproductive output of oysters by: sex ratio at maturity, larval output and spat settlement in locations where settlement is predicted, based on larval dispersal modelling. This will be assessed using standard histological techniques with haematoxylin and eosin staining, and hydrodynamic larval dispersal modelling.
c) monitor the disease status of re-laid oysters by routine monitoring for the incidence of Bonamia ostreae, B. exitiosa, and Marteillia refringens. Analyses will contrast existing OIE-approved protocols (molecular detection using PCR) for these notifiable pathogens, with other more sensitive assays. Full training will be provided by Portsmouth.
d) monitor the provision and enhancement of ecosystem services by relaid oyster by assessing changes in benthic biodiversity (epifauna and in fauna) at relaid oyster beds. This will employ biochemical measurements with direct sampling of seabed community and remote drop-down videography approaches – full training will be provided by Southampton.

Training:

All doctoral candidates will enrol in the Graduate School of NOCS (GSNOCS), where they will receive specialist training in oral and written presentation skills, have the opportunity to participate in teaching activities, and have access to a full range of research and generic training opportunities. GSNOCS attracts students from all over the world and from all science and engineering backgrounds. There are currently around 200 full- and part-time PhD students enrolled (~60% UK and 40% EU & overseas). Specific training will include:

We intend to recruit a student with suitable skills in organism physiology and/or benthic ecology and molecular biology. The student will be trained and supported in requisite techniques, including physiological assessments of performance, histology and histopathology as well as molecular parasitology and numerical modelling and coding in MatLab™. This will be provided by the supervisory team in Southampton and Portsmouth and via researchers in a wider network of native oyster research (ARCH-UK https://www.aquaculturehub-uk.com/; NORA https://noraeurope.eu/; Native Oyster Network UK & Ireland)