hrvatski

Utjecaj temperature na rast, razvoj i preživljavanje ličinačkih i postličinačkih stadija europske plosnate kamenice, Ostrea edulis (Linnaeus, 1758)

The basic factors influencing successful growth and development of larval and post larval stages are adequate nutrition and optimal temperature. The aim of our research was to determine the impact of various temperatures (17 ; 19.5 and 22 ºC) on the growth, development and survival of larval and early post larval stages. The experiment was conducted in duplicate in 6 polyethylene tanks. In each tank larvae were introduced that had a developed velum, in the stage of early shell formation prior to the D-larvae stage, and were stocked at a density of 7 larvae/ml. Optimal dissolved oxygen concentrations and maintenance of larvae and feed in suspension was assured by constant aeration, and salinity was maintained at 33 psu. The larvae were fed with pure monoculture flagellates, Isochyisis galbana and Tetraselmis suecia, for the first five days in a ratio of 95:5, and from the sixth day until metamorphosis with a monoculture mixture of I. galbana, T. suecia and the diatom Chaetoceros muelleri in a ratio of 40:25:35. The density of microalgae in the rearing tanks was maintained until metamorphosis at 100 cells/µL I. galbana equivalent, afterwards at 150 cells/µL. Following metamorphosis the ratio of flagellates and diatoms in a meal was 50:50. The survival rate, growth and development of larvae was monitored on a daily basis, and the water in the tanks was changed every second day. Larvae raised at a temperature of 22º C reached the pediveliger stage in 20 days when the average shell length was 301.9 µm, and survival at 59%. Larvae raised at 19.5 ºC reached the pediveliger stage in 26 days with an average shell length of 287.8 µm and statistically were not very different from the prior regime (p<0.05). Survival in this group was 55 %. Survival, development and growth of larvae raised at 17oC varied significantly (p<0.001) from that of larvae raised at higher temperature regimes, reaching the pediveliger stage in 34 days with an average of 230.5 µm, and survival of 21 %. The shell length of post larvae stages held at a temperature of 22ºC after a month was 6.2 mm and did not vary statistically (p<0.05) from larvae raised at 19.5 ºC (5.4 mm). Shell length of larvae raised at 17 ºC was 2.6 mm, and statistically did vary significantly from the results of the prior two regimes (p<0.001).

Ostrea edulis ličinke; temperatura; mrjestilište

nije evidentirano

engleski

The effect of temperature on the growth, development and survival of larval and post larval stages of the European flat oyster, Ostrea edulis (Linnaeus, 1758)

The basic factors influencing successful growth and development of larval and post larval stages are adequate nutrition and optimal temperature. The aim of our research was to determine the impact of various temperatures (17 ; 19.5 and 22 ºC) on the growth, development and survival of larval and early post larval stages. The experiment was conducted in duplicate in 6 polyethylene tanks. In each tank larvae were introduced that had a developed velum, in the stage of early shell formation prior to the D-larvae stage, and were stocked at a density of 7 larvae/ml. Optimal dissolved oxygen concentrations and maintenance of larvae and feed in suspension was assured by constant aeration, and salinity was maintained at 33 psu. The larvae were fed with pure monoculture flagellates, Isochyisis galbana and Tetraselmis suecia, for the first five days in a ratio of 95:5, and from the sixth day until metamorphosis with a monoculture mixture of I. galbana, T. suecia and the diatom Chaetoceros muelleri in a ratio of 40:25:35. The density of microalgae in the rearing tanks was maintained until metamorphosis at 100 cells/µL I. galbana equivalent, afterwards at 150 cells/µL. Following metamorphosis the ratio of flagellates and diatoms in a meal was 50:50. The survival rate, growth and development of larvae was monitored on a daily basis, and the water in the tanks was changed every second day. Larvae raised at a temperature of 22º C reached the pediveliger stage in 20 days when the average shell length was 301.9 µm, and survival at 59%. Larvae raised at 19.5 ºC reached the pediveliger stage in 26 days with an average shell length of 287.8 µm and statistically were not very different from the prior regime (p<0.05). Survival in this group was 55 %. Survival, development and growth of larvae raised at 17oC varied significantly (p<0.001) from that of larvae raised at higher temperature regimes, reaching the pediveliger stage in 34 days with an average of 230.5 µm, and survival of 21 %. The shell length of post larvae stages held at a temperature of 22ºC after a month was 6.2 mm and did not vary statistically (p<0.05) from larvae raised at 19.5 ºC (5.4 mm). Shell length of larvae raised at 17 ºC was 2.6 mm, and statistically did vary significantly from the results of the prior two regimes (p<0.001).

Ostrea edulis larvae; temperature; hatchery

nije evidentirano