• 한국양식학회지
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• 제12권4호
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• pp.323-331
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• 1999

Most of channel fish farming in Alabama are still earthen pond style, and filled by rainfall and runoff. The water levels of ponds are maintained with stand-pipe, and the effluent from ponds very little discharged at usual time except ant heavy rains and crop season. Overflow from ponds following rains occurs mostly in winter and early spring when stream flows high. In this study to know how much effluents fish ponds affected to streams which are nearby ponds, a survey carried out on the variation of water quality of seven streams and effluents at heavy rains. Water samples were collected at 14 sites on upstream (did not affected by effluents) and downstream(being affect by effluents), and sampled monthly from August 1997 to August 1998. There were no clear trends of difference in most water quality variables between upstream and downstream of catfish farms during a year. The effluents from ponds after heavy rains were not highly polluted, but sometimes have elevated concentrations of TSS. Nitrogen content of effluents was higher than that of routine streams , but phosphorus was not clear. From this result suggest than the effluents from catfish farm are not having adverse impacts on stream water quality still yet .

• 한국양식학회지
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• 제6권3호
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• pp.187-197
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• 1993

미국 알라바마주의 중서부 지역에 밀집되어 있는 차낼메기 양어장의 수질을 조사하여 양어장 물이 배출되는 그 주변 하천의 수질과 비교하였다. 양어장의 사육 밀도는 헥타르당 10,000마리였으며, 밤 동안(0000-0600)에는 산소를 공급하기 위하여 수차를 사용하였고, 먹이 공급은 일주일에 6일 동안 하였다. 메기 양어장에서 방류되는 사육수의 오염 정도를 알아보기 위하여 양어장의 표층 30cm와 저층에서 1990년과 1991년에, 계절별로 시료를 채취하여 수질 변수를 측정하였다. 수온, 용존산소, pH, 침전성물질, 총부유물질, 휘발성물질, 총인, 용존인, BOD, 총암모니아, 아질산염, 질산염, 그리고 총켈달질소의 평균값은 표층과 저층의 시료사이에 차이가 없었다 (P>0.05). 양어장의 수질은 주변 하천수에 비해서 오염도가 높았으며, 특히 질소와 인의 농도는 아주 높았다.

• 한국양식학회지
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• 제15권1호
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• pp.49-60
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• 2002

Research on practices for improving water quality in channel catfish Ictalurus punctatus ponds was conducted at the Auburn University Fisheries Research Station, Auburn, Alabama, in 1998 and 1999. The objective of this two-year study was to determine better management practices to enhance water quality and improve production efficiency. In the first year, oxidation of bottom soil by drying, tilling, and applying sodium nitrate was performed (dry-till and dry-till with sodium nitrate treatments). The second year, based on the results obtained during the first year, precipitation of phosphorus (P) from water by applying gypsum was compared to the dry-till treatment (dry-till and dry-till with gypsum treatments). Control ponds were not subjected to bottom drying, tilling, sodium nitrate, or gypsum treatment. Channel catfish fingerings were stocked at 15,000/ha. In the first year, water in ponds from dry-till and dry-till with sodium nitrate treatments had lower concentrations (P < 0.01) of soluble reactive P, nitrate ($NO_{3} ^{-}) and nitrite ($NO_{2} ^{-}) nitrogen (N), total ammonia ($NH_3$) nitrogen, total suspended solids and turbidity, and higher values of pH, Secchi disk visibility, total alkalinity, total hardness, and calcium ($Ca^{2+}) hardness than water in control ponds. Ponds of the dry-till treatment also had lower concentrations (P < 0.01) of total P and total N than control ponds. Total fish production and survival rate did not differ among the treatments (P > 0.05). The findings suggested that drying and tiling pond bosoms between crops could achieve water quality improvement. Applying sodium nitrate to dry, tilled pond bosoms did not provide water quality improvement. In the second year, the treatment with the best results from the first year, dry-till, was compared with a dry-till with gypsum treatment. Enough gypsum was applied to give a total hardness of about 200 mg/L, and gypsum was reapplied as needed to maintain the hardness. Compared to the control, dry-till and dry-till with gypsum treatments had lower concentrations (P < 0.01) of total and soluble reactive P, total N, and total $NH_3$-N, and higher concentrations (P < 0.01) of dissolved oxygen. Ponds of the duty-till with gypsum treatment also had lower concentrations (P < 0.01) of chlorophyll $\alpha$, chemical oxygen demand, and total alkalinity than the control. Total fish production and survival rate did not differ (P > 0.05) among the treatments. These findings suggest that drying and tilling pond bosoms between crops and treating low hardness waters with gypsum could achieve water Quality improvement.

• 한국양식학회지
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• 제14권2호
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• pp.67-71
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• 2001

Phosphorus is an essential element for growth and metabolism in fish. However high levels of phosphorus in the feed can lead to poor water quality of pond, and can also be a potential source of pollution, when pond water is released to the environment. In this study phosphorus supplemented diets containing 0.0, 0.9 or 1.9% of (dicalcium) phosphate were offered to channel catfish and changes in water quality of ponds and phosphorus levels in fish were measured. Higher level of (1.9%) supplementation of phosphorus in diet resulted in higher concentration of T-P and SRP in pond waters. Also it produced negative effects on fish production by lowering feed coefficient and rate of increment in body weight. Surplus phosphorus can affect fish growth and water quality of pond.

• 한국수산과학회지
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• 제9권4호
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• pp.261-263
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• 1976

1. 한국에서 처음으로 1975년 차넬메기의 종묘생산을 위해 지중산란을 시도하였으나 실패하였고 1976년 다시 지중산란을 시도하고, 또 Pen cage식 산란을 시도하면서 뇌하수체 hormone 주사도 하였으나 산란하지 않았다. 그러나, 전시용으로 수조에 둔 암컷 4마리, 수컷 1마리중 1쌍이 1976년 7월 산란하였다. 2. 산란한 수조의 조건은 실내에서 순환여과식사육제치로 pH는 $7.2\~7.4 $의 범위로 치유되었고 수온변화는 Table 2에 나타난 바와 같이 순간 평균 $19.3^{\circ}C$에 $23.6^{\circ}C$까지 서서히 변화하였다. 3. 산란에 실패한 지중에 처음 주입된 물은 지하수로서 실내의 전시용 수조에 사용된 물과 같은 수원의 물이며, 수온은 75년에는 순간 평균 $17.2\~29.8^{\circ}C$의 범위였고 76년에는 $19.7\~28.4^{\circ}C$로 산란에 적당한 범위내라고 인정되었으나 pH는 조류 및 수조의 광합성의 영향으로 $7.3\~9.5$의 범위로 변화가 심하였다. 이는 Nelson이 pH $8.5\~10.0$ 범위의 사육수에서 산란에 실패한 결과와 더불어 높은 pH는 차넬메기의 산란을 제어하는 요인으로 인정된다.

• Fisheries and Aquatic Sciences
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• 제1권2호
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• pp.192-200
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• 1998

This study was carried out to evaluate the effect of feeding higher protein feeds with lesser amount, but feeding the constant total protein input for all treatments, on water quality and nitrite toxicity in channel catfish ponds. There was no significant difference in survival rate among treatments $(P>0.05)$. Specific growth rate (SGR) for Treatment 1$(28\%\;protein\;and\;100\%\;of\;satiation)$ was significantly higher $(P>0.05)$ than for Treatment 3$(36\%\;protein\;and\;87.5\%\;of\;satiation)$, but not significantly higher than for Treatment 2 $(32\%\;protein\;and\;77.8\%\;of\;satiation)$ at constant digestible energy (DE), 3.08kcal/g (treatments 1, 2 and 3). At constant DE/P (treatments 4, 2 and 5), no significant difference in SGR was observed among treatments. Feed conversion ratio (FCR) slightly improved or improved as dietary protein level increased from $28\%$ to $32\%$ and feed allowance decreased by $12.5\%$, but did not improve as dietary protein level increased from $32\%$ to $36\%$ and feed allowance decreased by $22.2\%$, at constant DE and constant DE/P. There was no significant difference in water quality variables, such as total ammonia nitrogen (TAN), nitrite, chlorophyll a, soluble phosphorous concentrations among treatments, but significant difference in water quality variables over time as amount of feed fed increased $(P<0.0001)$. There was a trend toward increase in TAN and nitrite over time. A strong linear regression was observed between mean total ammonia nitrogen and nitrite for all treatments Y (Nitrite) =$0.04\times (TAN)+0.01$, $R_2=0.89$. Methemoglobin percent in the blood of catifish was not significantly different among treatments. And its mean value was $7.5\%$, which was relatively low, so that it was not serious problem in catfish production pond under these experiment conditions. There was the stronger linear regression between the percentage of Methemoglobin and the molar ratio of nitrite to chloride rather than nitrite alone: $Y\;(Methemoglobin\;\%)\;=\;58.45\;\times\;(NO^{2-}/Cl^-)\;+\;0.41,\;R^2=0.60$. These results indicate that deterioration of water quality has no strong impact on poor weight gain for $36\%$ dietary protein in this study.

• Fisheries and Aquatic Sciences
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• 제1권2호
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• pp.255-259
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• 1998

This study was designed to evaluate the economic analysis of channel catfish production in 1998 based on fish value and total feed cost. Catfish received higher protein feeds with lesser amount based on the dietary protein levels, but received the constant total protein input for all treatments. Weight gain per pond for treatment 1 $(28\%\;protein,\;100\%\;of\;satiation)$ was higher (P<0.10) than for treatment 3 $(36\%\;protein,\;77.8\%\;of\;satiation)$, but not significantly higher than for treatment 2 $(32\%\;protein,\;87.5\%\;of\;satiation)$ at constant DE. At constant DE/P (treatments 4, 2 and 5), weight gain per pond for treatment 5 $(36\%\;protein,\;77.8\%\;of\;satiation)$ was lower (P<0.10) than for treatment 2, but not significantly lower than for treatment 4 $(28\%\;protein,\;100\%\;of\;satiation)$. At constant DE, feed conversion slightly improved as dietary protein level increased from $28\%\;to\;32\%$ and feed allowance decreased by $12.5\%$, but did not improve further as dietary protein level increased from $28\%\;to\;36\%$ and feed allowance decreased by $22.2\%$. At constant DE/P, feed conversion improved as dietary protein level increased from $28\%\;to\;32\%$ increased and feed allowance decreased by $12.5\%$, but did not improve as dietary protein level increased from $28\%\;to\;36\%$ and feed allowance decreased by $22.2\%$ Total feed cost for treatment 1 was slightly, but not significantly higher than for treatments 2 and 3 at constant DE. At constant DE/P, total feed cost for treatment 5 was higher (P<0.05) than for treatment 2, but not significantly higher than for treatment 4. Total value of fish ($ /ha) produced for treatment 1 was highest and lowest was for treatment 5. Return above feed cost was highest for treatment 1 and nearly the same as treatment 2. Return over feed cost for treatments 3 and 4 were slightly lower than for treatments 1 and 2. Economic analysis showed that feeding fish the diet containing $28\%$ protein and 3.08 kcal/g DE to satiation and the diet containing $32\%$ protein and 3.08 kcal/g DE to $87.5\%$ of satiation produced the highest profit to farmer.

• 한국양식학회지
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• 제3권1호
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• pp.25-30
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• 1990

차넬메기(Ictalurus punctatus)는 전 세계적으로 중요한 양식어종이나 우리나라의 경우 대량산란이 이루어지지 않아 아직 양식 대상종으로 각광받지 못하고 있다. 본 연구는 차넬메기를 염색체공학 기법을 이용, 배수체를 생산하기 위한 일환으로 온도자극과 호르몬처리를 통해 산란을 유도하였다. 그 결과 처리하지 않은 군은 산란하지 않은 반면 온도자극시, $24^{\circ}C$로 부터 $30^{\circ}C$로 $6^{\circ}C$를 증가시킨 군이 $24^{\circ}C$ 부터 $27^{\circ}C$까지 온도를 증가시킨 군보다 약 4배 정도의 높은 산란유도율을 보였다. 본 실험에 사용된 호르몬 중 잉어뇌하수체를 어체중 1 kg당 4.4mg의 농토로 1$\~$3회 주사한 군은 $78.6\%$의 산란유도율을 보였고, human chorionic gonadotropin을 어체중 1kg당 1,100 IU의 농도로 1$\~$3회 주사한 군은 $66.6\%$의 산란유도율을 나타내었다.