Sara' G

Effects of trophic and environmental conditions on the growth of Crassostrea gigas in culture.

Abstract In order to study the possibility of exploiting protected marine areas, comparative data on the cultivation of the oyster Cassostrea gigas in the South Tyrrenian Sea are reported. The oysters were cultured at −7 and −13 m on long lines linked to artificial reefs. The observations, made during a 12-month period, were of the chemical-physical and trophic properties of the water column and growth rates of the oysters. Temperature ranged between 19.81 ± 4.67 °C at −7 m and 18.03 ± 3.03 °C at −13 m. Salinity showed typical Mediterranean values. The area presented oligotrophic features: the chlorophyll-a (CHLa) concentration ranged between 0.05 ± 0.01 and 0.04 ± 0.02 μg l −1 at −7 and −13 m, respectively. The labile particulate organic matter (LPOM) ranged between 344 ± 201 and 334 ± 228 μg l −1 at −7 and −13 m, respectively, and the CHLa carbon/POM carbon ratio (index of the autotrophic vs heterotrophic conditions) was never above 3%. POM concentration and POM gross energy content showed significant differences ( P