• Journal of Aquaculture
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• v.18 no.1
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• pp.13-18
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• 2005

This study was to investigate the effects of water temperature and food on the mass seed production of larval parrot fish, Oplegnathus fasciatus. Growth of the larvae reared at heated water temperature ($25.3^{\circ}C$) was significantly higher than that of the larvae reared at natural water temperature ($20.5^{\circ}C$). In addition, survival rate of the larvae at heated and natural sea water temperature were $24.0\%$ and $12.3\%$, respectively (P<0.05). Growth and survival rate of the larvae fed mixed diets of Nannochloropsis oculata, rotifer (Brachionus rotundiformis). Artemia nauplii, Tigriopus japonicus and artificial diets were significantly higher than that of the larvae fed only either rotifer or artificial diets (P<0.05). The average survival rate and total length of the larvae reared for 50 days after hatching were $22.5\%$ and 62.0$\pm$4.0 mm, respectively. Amount of consumed rotifers at one time feeding by a larva was rapidly increased with growth from 10.3 individuals per larva 5 day old to 65.5 individuals per larva 20 day old.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.753-757
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• 1999

The growth of rotifer, Brachionus rotundiformis was evaluated at different culture conditions. Rotifer was fed on condensed freshwater Chlorella. The productivity of rotifer in the high density culture system was compared to that of rotifer in the batch culture system, in which rotifer was fed on baker's yeast. The growth rate of rotifer increased as temperature increased in the culture system supplied with air or oxygen gas. The maximum density of rotifer in the culture systems supplied with air was in range of 16,300$\~$17,000 ind./ml at $24^{\circ}C$. In the culture systems supplied with oxygen gas, it ranged 26,300$\~$30,500 ind/ml at $28^{\circ}C$. When the concentration of dissolved oxygen in the culture system supplied with air reached to below 1 ppm or when the concentration of undissolved ammonia in the culture system supplied with oxygen gas reached 16.6$\~$22.6 ppm, the growth of rotifer decreased. When oxygen gas was supplied and pH was adjusted to 7, the maximum density of rotifer reached to 43,000 ind/ml at $32^{\circ}C$. The production costs for 10 billion rotifer in the high density culture and batch culture were 693,000 and 961,000 won, respectively. Therefore, it was concluded that the productivity of rotifer in the high density culture was higher than that in a batch culture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.748-752
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• 1999

This study was carried out to compare the growth and fatty acids composition of the rotifer (Brachionus rotundiformis) cultured in high density by the various enrichments and culture methods. The rotifer fed on condensed freshwater Chlorella was enriched with $\omega$-yeast, Algamac, Super Selco and marine Chlorella. In another culture method, the rotifer was cultured with enrichment supplements for 6 hours after feeding with condensed freshwater Chlorella supplement for 18 hour. The rotifer fed with condensed marine Chlorella for 24 hours without fieshwater Chlorella was used as a control group. Culture tanks (5 $\ell$ working volume) was immersed in a water bath ($28^{\circ}C$). The density of rotifer and dissolved oxygen level in water was stable in control group of rotifer cultured with condensed marine Chlorella for 24 hours and the n-3 HUFA content of rotifer was the highest among the rotifer culture methods. However, the density of rotifer and dissolved oxygen level in the groups of rotifers enriched with $\omega$-yeast, Algamac and Super Selco by methods were drastically decreased, The n-3 HUFA contents of rotifers enriched by Super Selco were higher than those of rotifer enriched by either $\omega$-yeast or Algamac in both methods. The results from this experiment indicated that supplementation of condensed marine Chlorella for 24 hour by the semi-continuous culture was effective for the improvement of the nutritional value of rotifer and it could provide the stable growth condition for rotifer culture in high density.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.342-347
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• 2002

Ciliates have the possibility of a new live food in marine finfish culture because of their wide range of body size, thin tell wall, show motility, and fast reproduction rate. In this research, six species of ciliates were isolated from south coast and salt pond in Korea. The fitness of these species as a live food was evaluated in terms of size, motility, suspensibility and cell density. As the result, Euplotes sp. (K-1) was found suitable to be a new live food which might substitute rotifers, Brachionus plintilis and B. rotundiformis in fish larvae culture. The modified $F{\emptyset}yn's$ Erdschreiberd media, MErds-2 with the addition of glycine, glucose and yeast extract increased six times higher growth rate of Euplotes sp. (K-1) than the basic F$\emptyset$yn's Erdschreiberd media. The optimum water temperature, pH and light intensity for this ciliates were $22.5^{\circ}C$, 8 and 2,000 lux, respectively, and its culture environmental range was relatively wide, On the other hand, this ciliate fed baker's yeast, Saccharomyces cererisiae grew up to 1,240 inds./mL with the inocula of 100 inds./mL within 7 days. The results of the study showed that Euplotes sp. (K-1) has a potential to be utilized as a new live food in fish larvae culture.

• Journal of Aquaculture
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• v.13 no.4
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• pp.277-284
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• 2000

Rabbitfish hatchlings were given a mixed food of rotifers (Brachionus rotundiformis) and trochophore larvae of oyster. Only the oyster-trochophore larvae were found in the gut of 62-h old fish larvae. The fish larvae, fed on rotifer and ciliate alone did not survive. However, their survival increased to 3.3 % on the 10th day after hatching, when trochophore was supplemented. Corresponding with the accelerated growth, the number of rotifers consumed increased from 11 in a 5-day old fish to 165 in a IS-day old fish. In a field ecosystem containing live diatom, Nannochloropsis oculata, rotifers and copepods, fish larvae were shocked and the oyster's trochophore larvae were fed from 2 to 7 days after hatching. A total of 76,000 seedling were produced after 50 days of hatching with 12.7 % survival. Mean total length and body weight were 65.6 mm and 3.4 g, respectively. Growth of body length (BL), body height (BH), body weight (BW) and head length (HL) as a function of the total length (TL) showed regressional relationships as follows; BL=0.8565 TL+0.0852 ($t^2$=0.9996); BH=0.3207 TL - 0.5052 (($t^2$=0.9641) BW=0.0652 TL2.3508 (($t^2$=0.9925); HL=0.2595 TL - 0.1898 (($t^2$=0.9901)