• 한국수산과학회지
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• 제54권5호
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• pp.751-760
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• 2021

This study investigated the changes in water quality parameters and microbial colonies when ozone was applied to a semi-recirculating aquaculture system (semi-RAS) for the olive flounder Paralichthys olivaceus (500 g in average weight). Concentrations of ozone-produced oxidants (OPO) in rearing tanks were maintained at 0, 0.014, 0.025 mg/L as Cl₂ for 26 days. Except total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate phosphorus, chemical oxygen demand, and total suspended solids decreased significantly with increasing OPO concentration in daily and weekly monitoring (P<0.05). Colony forming unit (CFU) counts of heterotrophic marine bacteria decreased in an OPO concentration-dependent manner. Overall reduction rates of microbial colonies in the treatments were 80% higher than those of the control (P<0.05). During the experiment, the OPO concentration-driven ozonation was reliably practiced without any adverse effects on the animals cultured in semi-RAS. Considering the biohazard, operating cost, and stability of ozonation, an OPO concentration of 0.014 mg/L would be sufficient to control water quality parameters and microbial colonies in a semi-RAS.

• 한국수산과학회지
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• 제51권6호
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• pp.688-696
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• 2018

This study investigated the effects of ozone-produced oxidants (OPO) on the growth, hematology, and histology of olive flounder Paralichthys olivaceus (average weight 500 g), raised in an ozonated semi-recirculating aquaculture system. The system was ozonated to maintained OPO concentrations of 0.004 (Control), 0.014 (OPO15), and 0.025 (OPO25) mg $Cl_2/L$ in culture tanksfor 26 days. The specific growth rate, feed conversion ratio, and survival rate did not significantly differ among the groups (P>0.05), while the daily feeding rate decreased OPO-dose-dependently (P<0.05). OPO appeared to affect the gill, hepatopancreas, and kidney tissues of fish from ozonated tanks. Hematologically, OPO affected some blood indices. The levels of chloride, glucose, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase were significantly increased in the ozonated groups, while the total cholesterol and cortisol decreased dose-dependently. These results imply that long-term exposure of olive flounder to an OPO concentration ${\geq}0.014mg\;Cl_2/L$ might result in damage to the gill, hepatopancreas, and kidney tissues and cause physiological stress, albeit with no apparent short-term effects on growth or survival.

• 한국수산과학회지
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• 제38권6호
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• pp.353-358
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• 2005

The present study investigated the feces production rate and fecal nitrogen production ratio of abalone, Haliotis discus hannai fed seaweed, Undaria pinnatifida. The abalone, with shell lengths of 3 cm, 5 cm, and 7 cm, were tested at temperatures of $12^{\circ}C$, $16^{\circ}C$, and $20^{\circ}C$ in a semi-recirculating aquaculture system. Under the given experimental conditions, the weight specific feces production rate (FPw) of the abalone increased with the decrease of shell length and the increase of temperature. The relationship of the FPw was. $FPw=-3.092+206.573/T - 1916.8/T^2+0.141L -0.037L^2(r^2=0.9412)$. In addition the abalone produced 17.8-22.5% of fecal material against ingested seaweed, Undaria pinnatifida, and $18.4-22.4\%$ of nitrogen ingested total nitrogen.

• 한국수산과학회지
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• 제28권4호
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• pp.457-468
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• 1995

현재 유수식 방법으로 양식되고 있는 넙치(Paralichthys olivaceus)의 육상수조 양식에서 환수율, 월동시가온 및 양식배수 등의 문제를 해결하기 위하여, 실제 양식장에 설치한 반폐쇄식 순환여과 사육시스템을 이용하여 1992년 2월부터 1994년 1월까지 2년 동안(실험 I , 실험II) 넘치를 사육하면서 그 실용성을 연구하였다. 실험 I에서는 평균전장 7.5cm, 평균체중 3.4g, 실험II에서는 각각 5.0cm, 1.8g의 종묘를 사용하였다. 실험 I의 사육수 용존 무기태질소량은 $NH_4-N\;0.247-0.512ppm,\;NO_2-N\;0.010-0.043ppm,\;NO_3-N\;0.108-0.342ppm$ 실험II에서는 각각 0.091-0.715ppm, 0.002-0.045 ppm, 0,007-0.277 ppm 범위에서 변화하였다. 일간섭식률은 실험 I $0.67-2.41\%$, 실험II $0.69-2.22\%$, 사료효율은 각각 $34.8-59.8\%,\;40.5-88.4\%$였다. 실험 I에서의 어체는 사육 340일만에 전장 40.0-42.8cm, 체중 695.0-852.6g으로 성장하였고, 실험II에서는 사육 365일후에 전장 36.7-39.7cm, 체중 552.4-706.4g으로 자라났다. 사육종료시 어체의 평균 생존율은 실험 $192.0\%$, 실험II $96.0\%$였다. 어체의 체표면적이 수조바닥을 덮는율(covering rate)은 넙치의 수용밀도의 지표로 활용 가능하였다. 사육시 어체의 최대 수용량은 실험 I에서 덮는율 2.2, 중량 $34.1kg/m^2$였고, 실험II에서는 각각 $2.6,\;36.3kg/m^2$였다. 순환여과식 양식시스템은 현행의 유수식 양식시스템에 비해 양식 생산성 및 연안 환경오염 방지에 기여도가 높은 양식방법으로 평가되었다.

• 한국수산과학회지
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• 제52권5호
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• pp.482-495
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• 2019

This study compared the productivity of fish and vegetables grown using the hybrid biofloc technology-aquaponics (HBFT-AP), a semi-recirculating aquaculture system (SRAS), and hydroponics (HP). For the study of fish productivity (HBFT-AP vs. SRAS), fish were provided feed containing 3.0% monobasic potassium phosphate (MKP) for 18 weeks. After the 18-week feeding trial, the average weight of the sampled population (n=100) was not significantly different (P>0.05), while hematocrit (PCV, %), hemoglobin (Hb, g/dL), and plasma K (mEq/L) were significantly different (P<0.05) between the two groups (HBFT-AP: 47.83%, 15.48 g/dL, and 1.39 mEq/L; SRAS 34.83%, 11.81 g/dL, and 2.48 mEq/L). Leaf vegetable productivity (HBFT-AP vs. HP) was compared in three experiments (EXP 1-3), and slower growth was observed in both groups in EXP 2, in which pH was maintained at 5.0 or less throughout the experiment. During the 18-week feeding trial, total ammonia nitrogen (TAN), $NO_3-N$, and $PO_4-P$ levels increased with time in the HBFT-AP system, while the concentration of $NO_2-N$ remained below 0.1 mg/L throughout the study.

• 한국동물생명공학회지
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• 제35권3호
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• pp.279-288
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• 2020

Changes of gonadal morphology and mRNA expression patterns of vitellogenin were investigated in Siberian sturgeon Acipenser baerii (Chondrostei) during its early gonadal maturation period. Early differentiations and morphological transitions of both ovaries and testes appeared to occur actively until the age of 3 years, however from then on, the maturation patterns to full maturity were largely gender-dependent, in which males showed a faster progression of maturation than did females while females experienced a steady-state progress with a lagged interval before entering the final maturation. Expression of vitellogenin mRNAs are closely correlated with transitional patterns of gonadal appearances. In both females and males, hepatic mRNA levels of vitellogenin exponentially increased in the earliest interval (up to 1-year-old). However, in subsequent periods, vitellogenin expression in females continued to increase with age, whereas in males, the expression stabilized at a younger age. Nevertheless, at the age older than or equal to 7-year-old, fully matured individuals showed a quite low level of vitellogenin expression in both females and males. Collectively, results from this study could be useful as a fundamental guideline to address the gonad maturation of this sturgeon species, which is helpful for making practical decisions about farming practices and management for caviar production on local sturgeon farms.