hrvatski

Uzgoj i usporedba rasta i preživljavanja ličinki kamenice, Ostrea edulis (Linnaeus, 1758), u različitim uzgojnim sustavima

The first part of the experiment involved the comparison of growth and survival of oyster larvae, Ostrea edulis (Linnaeus, 1758), in stationary and flow through systems. The stationary system was composed of polyethylene tanks 1 m³ in size. Aeration assured sufficient concentrations of dissolved oxygen and the maintenance of larvae and phytoplankton in suspension. Tank water was changed every 48 hours, and temperature was maintained at 21±1º C. The larvae were fed with an optimal ratio of flagellates and diatoms (65:35), and the number of algae in the tanks was maintained at 100 larvae/ml of Isochyisis galbana equivalent. The flow system was constructed as the continuous flow of ambient sea water (temperature 21±1º C) which, prior to entry into the tanks, was filtered through a plankton net of a mesh size of 100 µm in order to separate larger plankton organisms unsuitable for the feeding of larvae. Water flow was stopped 1h daily when the larvae were fed with algae raised in the laboratory as supplementary feed, at a density of 200 larvae/ml Isochyisis galbana equivalent. Following 21 days the average shell length of developed pediveliger larvae in the stationary system was 265 µm, and in the flow-through system was 238 µm. Survival of larvae until metamorphosis in the stationary system was 54% and statistically varied significantly (p<0.001) from survival in the flow-through system (22%). In the second part of the experiment, a recirculating system was designed and the success of the attachment of developed pediveliger larvae on oyster shell grains (“cultchless” technology) was measured. This was compared to their attachment on traditional collectors in a stationary system. Larvae were raised in a stationary system until reaching a size of 250 µm, following which a part was transferred to a recirculation “upwelling” system. Results showed that the success of spat collection on classic collectors is 20% greater than on oyster shell grains. Considering the possibility of further controlled culture of spat produced with “cultchless” technology, the accounted differences are most likely economically acceptable.

Ostrea edulis ličinke; mrjestilište; prihvat; uzgojni sustav

nije evidentirano

engleski

Culture and comparison of growth and survival of oyster larvae, Ostrea edulis (Linnaeus, 1758), in various culture systems

The first part of the experiment involved the comparison of growth and survival of oyster larvae, Ostrea edulis (Linnaeus, 1758), in stationary and flow through systems. The stationary system was composed of polyethylene tanks 1 m³ in size. Aeration assured sufficient concentrations of dissolved oxygen and the maintenance of larvae and phytoplankton in suspension. Tank water was changed every 48 hours, and temperature was maintained at 21±1º C. The larvae were fed with an optimal ratio of flagellates and diatoms (65:35), and the number of algae in the tanks was maintained at 100 larvae/ml of Isochyisis galbana equivalent. The flow system was constructed as the continuous flow of ambient sea water (temperature 21±1º C) which, prior to entry into the tanks, was filtered through a plankton net of a mesh size of 100 µm in order to separate larger plankton organisms unsuitable for the feeding of larvae. Water flow was stopped 1h daily when the larvae were fed with algae raised in the laboratory as supplementary feed, at a density of 200 larvae/ml Isochyisis galbana equivalent. Following 21 days the average shell length of developed pediveliger larvae in the stationary system was 265 µm, and in the flow-through system was 238 µm. Survival of larvae until metamorphosis in the stationary system was 54% and statistically varied significantly (p<0.001) from survival in the flow-through system (22%). In the second part of the experiment, a recirculating system was designed and the success of the attachment of developed pediveliger larvae on oyster shell grains (“cultchless” technology) was measured. This was compared to their attachment on traditional collectors in a stationary system. Larvae were raised in a stationary system until reaching a size of 250 µm, following which a part was transferred to a recirculation “upwelling” system. Results showed that the success of spat collection on classic collectors is 20% greater than on oyster shell grains. Considering the possibility of further controlled culture of spat produced with “cultchless” technology, the accounted differences are most likely economically acceptable.

Ostrea edulis larvae; settlement; oyster hatchery systems

nije evidentirano