engleski

Interactive effects of temperature and salinity on the rate of concentration of Escherichia coli in mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis)

Being filter-feeding organisms, bivalves present a potential health hazard to consumers due to pathogens which may be present in the marine environment. The simultaneous effect of temperature and salinity on the rate of concentration of indicator microorganism Escherichia coli (EC) in mussels (Mytilus galloprovincialis) and oysters (Ostrea edulis) was studied in experimental conditions with different concentrations of EC in seawater. The experiments were carried out in 3000 L tanks and were performed within the natural range of temperature (12oC, 18oC and 24oC) and salinity (37 psu and 32 psu) and within the common range of EC concentration in the coastal Adriatic Sea. In order to determine the influence of temperature and salinity on the rate of concentration of EC in bivalves, we used short- time experiments confined by the periods of linear increase of concentration of EC in bivalves which lasted between 1 and 3 hrs. The results clearly showed that the rate of EC concentration in mussels and oysters depended on the concentration of EC in the surrounding seawater and on the rate of filtration of seawater by bivalves highly controlled by temperature and salinity. Moreover, the effect of temperature and salinity on concentration rate affected one another regardless the concentration of EC in tanks. The rate of EC concentration was significantly higher in mussels than in oysters. In mussels, variations in salinity had more effect than variations in temperature in bringing about changes of the concentration rate, whereas in oysters the result was reversed. Furthermore, in mussels, temperature had stronger effect in changing concentration rate at salinity of 37 psu than at salinity of 32 psu, whereas in oysters the result was the opposite.

mussel (Mytilus galloprovincialis) ; oyster (Ostrea edulis) ; Escherichia coli ; concentration rate ; temperature ; salinity

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