• Fisheries and Aquatic Sciences
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• 제26권8호
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• pp.461-469
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• 2023

The objective of this study was to evaluate how the tank colours may change the effects of extreme temperature on the survival, growth, and quality of juvenile golden trevally (Gnathanodon speciosus). The experiment was set up with fifteen treatments of five tank colours (blue, red, yellow, grey, and white) and three temperatures (30℃, 32℃, 34℃) with three replications. Fish performance was assessed for four weeks. The results showed that tank colours and elevated temperatures affected the quality of golden trevally juveniles. The survival and growth rate of fish tend to decrease gradually, but the deformation rate of fish tended to increase in the order of tank colours: red, yellow > grey, blue, and white. The growth and survival rate of fish gradually decreased when the rearing temperature increased from 30℃ to 34℃ and this effect was independent of tank colors. Importantly, the deformation rate increased under elevated temperature, particularly in blue and white tanks with potential long-term effects. It is, therefore, not recommended to use blue and white tanks for rearing the golden trevally juveniles, particularly during extremely high temperatures from heatwave events.

• 한국수산과학회지
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• 제40권2호
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• pp.73-78
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• 2007

The suitability of a flexible fiber filter for removing suspended solid (SS) in a recirculating aquaculture system was evaluated. This study focused on variation in the performance with a change in filtering time, influent water quality, and filtering mode duration. The particle distribution diagram of the filter effluent showed that the number of particles bigger than $5-8{\mu}m$ decreased dramatically, and the removal efficiency exceeded 80%. Although the removal efficiencies of SS and chemical oxygen demand (COD) were dependent on the quality of the influent, the SS and COD concentrations of the effluent were not affected by the influent concentrations. This was despite the deterioration if water quality after feeding in the rearing tank. The performance of the filter was not affected by the filtering mode duration, feeding conditions, or filtering time. The SS concentration and turbidity of the recirculating-type rearing tank were 30% and 50% lower, respectively, than of the a non-recirculating-type rearing tank under the same operating conditions. The flexible fiber filter was applicable to a recirculating aquaculture system that uses plenty of seawater, based on its low filtering resistance $(2kg_f/cm^2)$, high flux $(330m^3/m^2/hr)$, and high fine particle removal efficiency (80%, $5-8{\mu}m$).

• 한국수산과학회지
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• 제34권1호
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• pp.70-76
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• 2001

우리나라의 실정에 적합하고 실용적인 순환 여과식 양식 시스템을 개발하여 package 형태로 개발하기 위하여 $2.5 m^3$ 규모의double drain 형태의 사육조와 침강성 고형물질을 제거하기 위한 침전조, 부유성 고형물의 제거를 위한 floating bead filter, 용존고 형물을 제거하기 위한 포말 분리기와 암모니아성 질소를 제거하기 위한 회전 원판 반응기를 조합한 순환 여과식 양식 시스템을 설계하고 제작하였다. 본 시스템에 평균 어체중 392.8g의 나일 틸라피아 173마리를 수용하여 일간 보충수를 사육조 용적의 $10\%$를 사용하여 14일간 어류사육을 실시한 걸과 사육조의 수질을 보충수와 거의 동일한 수질로 유지할 수 있었으며 사료계수 1.4, 일간 성장률 0.64를 얻을 수 있었다.

• 한국양식학회지
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• 제7권1호
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• pp.9-20
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• 1994

전복을 육상에서 사육하기 위한 시설형태 및 적절한 사육밀도의 구명을 위해 수조형태 및 수용밀도별 사육실험을 한 결과 1. 수조형태, 단별에 따른 성장과 생존율의 차리는 인정되지 않았고, 유수식과 순환식사육의 비교에서는 유수식의 성장도와 생존율이 좋았다. 2. 수조단수별 (3단)에 따른 성장과 생존율의 차이가 인정되지 않아 동일량의 사육수로 단위면적 당 3배의 생산이 가능하였다. 3. 밀도별실험에서 $1000-2000마리/m^2$로 수용한 각장 약 20mm치패는 수용밀도에 따른 성장 차가 없었지만, 각각 200-600, 100-300마리의 밀도로 수용한 각장 약 40mm와 50mm의 치패는 수용밀도가 낮을수록 성장이 빨랐다. 4. 일간섭식률과 사료전환효율은 밀도가 낮을수록 높았고, 치패 크기가 작을수록 높았다

• 한국해양생명과학회지
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• 제1권1호
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• pp.18-24
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• 2016

Since April 2012, doctor fish in the breeding tank and in the quarantine tank in Hanwha Aquaplanet Yeosu Aquarium have been dying, accompanied by diffuse bleeding around the mouth, in the chin, and at the bottom of the abdomen. In this study, the cause of death would be examined through the bacteriological study of doctor fish and the rearing water quality in the aquarium. The water quality and the bacterial counts of the rearing water in the exhibit tank and in the quarantine tank were analyzed once a week, starting from August to November 2014. Water quality was measured based on the following data: temperature was in the range of 24.5~26.8℃, pH at 6.77~7.94, DO at 6.15~8.61 ppm, ammonia at 0~0.93 ppm, nitrite at 0.009~0.075 ppm, and nitrate at 1.1~40.9 ppm. Studies revealed that the differences in these water quality factors were not related to the death of doctor fish. Bacterial counts in the rearing waters of Garra rufa slightly increased to 10³~10⁴ CFU/ml, just before the death of the doctor fish. Twelve strains of bacteria were isolated from the dead fish and rearing waters. The isolates were identified as Aeromonas veronii, Citrobacter freundii, Pseudorhodoferax aquiterrae, Shewanella putrefaciens, and Vibrio anguillarum on the basis of 16S rRNA gene sequences. The most dominant species was C. freundii, which showed medium sensitivity to florfenicol and norfloxacin, and was resistant to amoxacillin, doxycycline, oxytetracycline, tetracycline, and trimethoprim. Ten isolates were confirmed to be pathogenic to the doctor fish. Doctor fish infected with C. freundii and S. putrefaciens showed high mortality in the experimental groups. These results indicate that the variation in bacterial numbers in the rearing water was related to the death of doctor fish. C. freundii and S. putrefaciens were directly implicated in causing the death of doctor fish in the aquarium.

• 한국수산과학회지
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• 제50권4호
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• pp.378-387
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• 2017

This study was performed to isolate bacteria that could control the nitrite levels in a biofloc technology (BFT) culture tank. Nitrite-eliminating bacteria were isolated from a BFT culture tank rearing goldfish, and the isolated bacterium exhibiting the most potent nitrite eliminating ability was labeled as the "NOBSB1" strain. Sequencing the 16S rRNA revealed that NOBSB1 is a species in the genera Bosea. NOBSB1 had the following characteristics with regard to nitrite removal: (1) it removed nitrite by functioning heterotrophically in the presence of a carbon source (sugars); (2) it eliminated nitrite most effectively within a temperature range of $20-30^{\circ}C$, but its activity decreased at temperatures above $35^{\circ}C$ and below $20^{\circ}C$; (3) it had optimum nitrite removal ability within a pH range of 6.0-8.0; (4) it removed nitrite more effectively under hypoxic than aerobic conditions. NOBSB1 inoculation did not decrease ammonia or nitrate levels, but eliminated nitrite in a BFT culture tank rearing common carp (Cyprinus carpio). After inoculating the NOBSB1 strain in a BFT culture tank, NOBSB1 controlled and sufficiently reduced the nitrite concentration in the tank.

• 한국양식학회지
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• 제13권3호
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• pp.223-230
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• 2000

사육수에 광물미립자를 현탁시켜 노폐물을 흡착, 분해시킨 후 이를 분리, 배출시킴으로서 사육수를 정화시켜 재 사용할 수 있다는 가설 하에 사육수조와 포말분리장치로만 구성된 사육수 재사용 시스템에서 광물미립자를 현탁시켜 넙치를 실험사육 하였다. 두 종류의 가공황토 (processed residual reddish soil, 50 $\mu$ 이하)와 돌로마이트 (dolomite, 50 ${\mu}$이하) 미립자를 사육수에 현탁시키고 포말분리장치로 이를 분리, 배출시킴으로서 사육수를 정화하였다. 직경 4.8 m의 원형사육수조(사육수량 10 $m^2$), 사육수 순환을 시간당 2회전, 재사용을 90%, 수온 17${\pm}$1$^{\circ}C$에서 평균체중 23.1 g의 넙치 치어(5,555마리, 총중량 128 kg)를 75일간 사육하여 평균체중84.6 g (5,532마리, 총중량 468 kg)으로 육성하였다. 최종수용밀도는 26.0 kg/$m^2$였다. 실험기간 동안 어병은 관찰되지 않았다. 사육수에 광물입자를 현탁시켜 사육수 중의 노폐물을 흡착, 분해시킨 후 포말분리장치로 이를 배출시킴으로서 사육수를 정화하여 재사용하는 방법은 새로운 사육수 재사용 어류양식시스템으로서 가능성이 있다.

• 한국수산과학회지
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• 제16권2호
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• pp.103-110
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• 1983

The main purpose of the present study is to evaluate a revolving plate type biofilter system for mass culture of eel(Anguilla japonica) based on the experimental rearing for 120 days (Oct. 1982-Feb. 1983). Water quality changes, growth efficiency of fish and fish disease treatment were critically evaluated. A revolving plate type biofilter system was designed(Fig. 1). The system consisted of a glass tank (150 l), a revolving plate biofilter and a settling tank(150 l). The biofilter consisted of 60 submerged quadriangular plates ($28{\times}37$ cm) and 30 revolving plates (32 cm diameter) for a total of 19.0 $m^2$ of surface area. The revolving plates were made to rotate 10 time per minute, The total water volume of the rearing system were 300 l, and everyday 1/3 of the total water volume were changed with freshly prepared water. In the rearing system a total of 2 kg of eel (1,500 individuals, mean weight:1.3 g) were reared fed on the pellet feed and the dough feed. The growth efficiency were much better for the pellet feed (FC: 1.79) compared to the dough feed (FC: 3.56). During the experimental rearing water quality control was satisfactory. Total ammonia concentrations were 0.38-0.59 ppm and nitrite concentration were 0.83-1.19 ppm. On the other hand alkalinity decreased from 176ppm just after the water change to 17ppm just before the water change. The low alkaline condition was compensated by the regular change of water. Epidemics of parasitic gill-flocks (Pseudodactvlogylus sp.) was observed, and they were easily eliminated by the treatment of DDVP (1.0 ppm). Trichodina sp. and Costia sp. were observed, and they were also controlled by the treatment of potassium permanganate (4.0 ppm).

• 한국수산과학회지
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• 제44권4호
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• pp.359-365
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• 2011

This study was conducted to investigate the production, elver stocking, rearing facilities and rearing method of eel culture to determine aquaculture management conditions for optimal rearing of eel Anguilla japonica. The production of eel culture was evaluated by the proportion of eels from the main inland fin fish species production in Korea. Elver stocking was assessed by the elver stocking densities of pond and recirculation culture. Rearing facilities were investigated according to the rearing tank size proportion of the pond and recirculation culture. We selected sample farms by region and by size. We visited sample farms and recorded the number of elvers stock for pond area, size of tanks, feed and feed quantity, and the size and number of harvest eels. The production capacity of Jeollanam-do and Jeollabuk-do were 71.9% and 21.3% respectively. This production quantity represented 93.2% of the total Korean eel production quantity. In Jeollanam-do, there are 236 eel farms, 202 pond farms, and 34 recirculation aquaculture facilities. The elvers' first density data by each aquaculture method revealed that elvers' first density varied more in recirculation system farms, as compared to pond aquaculture. In intensive pond farms, the elvers' first density decreased as the size of farm increased. There was a correlation between the size of tank(x) and the facility of a water wheel for dissolved oxygen in pond culture systems(y=0.022x-0.494; $R^2$=0.860). Another strong correlation was found between the weight of eel(x) and eel density(y) in pond culture systems(y=283.5x-0.27; $R^2$=0.992). Finally, there was a strong correlation between the length of eel(x) and the weight of eel(y) in intensive pond culture(y=0.0005x-3.2783; $R^2$=0.9775). The final survival rate did not differ significantly among pond sizes and culture types.

• 한국수산과학회지
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• 제2권1호
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• pp.87-91
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• 1969

보리새우의 대량종묘생산을 목적으로 대형콘크리이트수조 A ($3.4\times1.9\times1.0m$)와 2개의 소형콘크리이트수조 B와 C($1.45\times0.85\times1.0$)를 이용하여 유생사육실험을 하였다. 1) 산난후 제1기 조이야까지의 발생기간은 사육수조에 차이없이 수온 $23^{\circ}C$ 내외에서 1.5-2일이 소요되었다. 그러나 조이야기 이후 차이가 생겨 Post-larva까지의 변태기간은 수조A에서는 산난후 19-20일, 수조B에서는 15-16일, 수조C에서는 16-17일이 각기 소요되었다. 2) 유생의 체장은 3개의 수조간에 차이가 없었다. 3) Post-larva는 산난후 36-40일경에 치하로 되었다. 4) 유생 사망률은 전유생 기간중 제1기조이야에서 제2기조이야로 변태하는 기간에 가장 높아서 수조A가$51.39\%$ 수조B가 $50.70\%$, 수조 C는 $31.90\%$를 나타내었으며 마이시스기이후는 비교적 안정된 상태를 나타내었다. 5) 노우플리우스기로부터Post-larva까지 기간의 유생 총사망률은 각수조 비슷하게 $75\%$ 내외를 나타내어 전체적으로 약 $25-30\%$의 종묘를 생산할 수 있었다.