BEST ADRIA - Sensitivity of commercially important bivalves from eastern Adriatic aquaculture to variations in environmental conditions
Shellfish aquaculture is among the fastest growing food production sector due to increased worldwide demand for seafood. Optimal environmental conditions in the Adriatic provide nearly ideal conditions for fish and shellfish aquaculture. Aquaculture of bivalves in the eastern Adriatic is traditionally carried out in situ and therefore relies merely on the farming habitat characteristics. The intertidal zones of sheltered bays and estuaries are suitable areas for bivalve cultivation. Adriatic coastal microenvironments generally display spatio-temporal heterogeneity of hydrological conditions, nutrients availability and are typically under risk from anthropogenic pollutants that may be delivered from land-based sources. These external stressors, alone or in combination, may directly affect the overall physiological performance of bivalves and consequently their ability to counteract the colonization by pathogens and non-resident microbes. In particular, bacteria of the genus Vibrio, naturally occurring in seawater, have been associated to diseases outbreaks in aquaculture and can be transmitted to humans by infection of open wounds and consumption of contaminated shellfish as raw or undercooked products. Currently available information on microbial community and susceptibility to potentially pathogenic bacteria is apparently sparse or outdated for bivalves from the eastern Adriatic. Further, coastal inshore areas may be occasionally subjected to disturbances of varying frequency and intensity, such as sudden atmospheric precipitations or heat and cold waves. Such extreme fluctuations of weather conditions have nowadays been largely ascribed to global warming. Yet, it is still unknown whether and to what extent, climate changes intensification foreseen in the near future will affect the aquaculture practice within sensitive ecosystems such as Adriatic coastal areas.
Productivity and sustainability of bivalve aquaculture along the eastern Adriatic will require significant improvement of basal knowledge on the interaction between farming habitats and commercially valuable bivalves. In that respect, understanding how locally modulated environmental conditions – natural and anthropogenic, may hamper the ability of farmed bivalves to counteract the physiological stress and consequently to withstand bacterial infection will be of paramount importance. This aspect will become even more relevant in near future, given the negative impacts of global climate change in combination with more intense pressure imposed by anthropogenic stressors anticipated for this marine coastal region.
GOALS OF THE PROJECT:
1) to evaluate the physiological response of mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) from two breeding locations in the Lim Bay and Mali Ston Bay (Bistrina) to changes in natural and anthropogenic environmental conditions
2) determine the detailed structure of the community of Vibrio bacteria, with an emphasis on potentially pathogenic species, in seawater, sediment and shellfish tissues
3) to determine the structure and spatio-temporal dynamics of the microbial community of seawater, sediment and bivalve tissue