• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.354-359
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• 2009

The productivity of ultra-small rotifer, Synchaeta kitina was investigated at the exchange rate of culture water (10, 20, 30, 40 and 50%) and initial inoculation densities (250, 600 and 900 inds. per mL) in semi-continuous culture. Also, the possibility of mass culture was investigated in a 100 L culture tank. Tetraselmis suecica was used as the feed for S. kitina in all experiments. The production of S. kitina increased with an increase in exchange rate of culture water. The highest production ($82.0{\times}10^5$ inds.) was achieved at 40% exchange rate of culture water. The production of S. kitina increased with an increase of initial inoculation density during the first week and the highest total production ($17.4{\times}10^6$ inds.) was achieved at 900 inds. per mL of initial inoculation density. However, on the second week, all treatments were not significantly different in total production (P>0.05). During the two weeks, total production of S. kitina at 900 inds. per mL of initial inoculation density was higher than at 600 inds. of initial inoculation density, but there was no significant difference (P>0.05). In the 100 L culture tank, density of S. kitina was kept from 516 to 890 inds. per mL and S. kitina was daily harvested $15.5{\times}10^6$ to $26.7{\times}10^6$ during the experimental period. The production cost for 100 million rotifers in semi-continuous culture was 63,656 won. The results from this study indicate that the optimal exchange rate of culture water and initial inoculation density for the semi-continuous culture of ultra-small rotifer, S. kitina are 40% and 600 inds. per mL, respectively.

• Journal of Aquaculture
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• v.21 no.2
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• pp.70-75
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• 2008

We investigated the optimum salinity and temperature conditions for mass culture of ultra-small rotifer Synchaeta kitina. In the salinity experiment of ranging within 5 and 30 psu, the population growth of S. kitina increased continuously up to 20 psu, and then decreased over 20 psu. Their maximum density showed 390.1 inds./mL at 5 psu. A pre-reproductive phase was shortened in low salinity than high salinity. Also, the maximum offsprings and maximum lifespan and lifespan of the female were 13.4 inds. and 5.9 days, respctively at 5 psu. In the temperature experiments of ranging within 16 and $32^{\circ}C$, the population growth of S. kitina increased continuously up to $24^{\circ}C$, and then decreased over $24^{\circ}C$. The highest maximum density showed 492.8 inds./mL at $16^{\circ}C$. Their offsprings increased significantly with temperature decrease, and the maximum number of offsprings per female was 9.2 females. at $16^{\circ}C$. Their lifespan increased with temperatures decrease and the longest lifespan was to 5.5 days at $16^{\circ}C$. From these results, we conclude that the optimum culture conditions of S. kitina is 5 psu and $16^{\circ}C$.

• Journal of Aquaculture
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• v.21 no.2
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• pp.76-81
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• 2008

We investigated the food-effect for ultra-small rotifer Synchaeta kitina cultured under a individual and community by several diets: 3 single trials(Tetraselmis suecica, TET; Isochrysis galbana, ISO; Marine Chlorella ellipsoidea, CHL) and 3 trials with a mixture of 2 species. The rotifer was cultured on the different feeding concentrations. In the individual cultures, the maximum number of offsprings and maximum lifespan of the female investigated to 5.8 inds. and 12.7 days in TET trial, respectively. Values of the developmental phases of the rotifer fed with T. suecica were higher than those of trials without T. suecica. Also it approached faster to maturation level. In the community cultures, the maximum density of TET+CHL trial elevated up to 1,569 inds./mL. But, CHL and ISO showed a poor growth rate and maximum density. The offsprings of the female increased continuously when fed by T. suecica trial, up to $10{\times}10^3$ cells/ind./day. As the quantity of supplied diet was lowered their lifespan were decreased. But, the maximum density and growth rate in the community cultures showed the highest value in the $10{\times}10^3$ cells/ind./day. The efficient food for mass culture of S. kitina was T. suecica, and optimum concentration of their food was 10,000 cells for an individual.