Table 5. gives nutrient content in water from 29 July in the
first year to 20 July in the third year. The samples were taken
in two sites (S1 – the site of cages and S3 - control station at
the entrance of the bay), at the depth of 3m and at the depth of
10 m. In the site S1 minimum concentration of phosphates
was recorded at 3m depth in the warmer period of year (June
and July) what corresponded to maximum food supply to the
fish and maximum nutrient loading in the environment
throughout uneaten food and feces.
High nutrient concentrations were also recorded in August
and September when fish biomass in the cages is was the
largest. Similar situation was recorded in S3. According to
Croatian regulations (N. N. 2/08/84) maximum allowedphosphates concentration is: 0.025 mg/l (for I and II category
of coastal sea). That value was exceeded three times in S1 and
four times in S3. Nitrate concentrations were low for both
depths and for both sites; those concentrations were below
maximum allowed concentrations (1 mg/l). In the both sites
nitrite concentration was below maximum allowed
concentration for I and II category of coastal sea (0.01 mg/l);
maximum concentration was found on February 17th in the
fourth year of monitoring in S3. In the great majority of the
samples the nitrites were not found.