• Journal of Aquaculture
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• v.22 no.1
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• pp.1-4
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• 2009

A 10-week feeding trial was conducted to investigate the effects of feeding rate on growth and body composition of adult flounder during the summer season. Three replicated groups of the fish (initial mean weight of $535{\pm}4.1\;g$) were hand-fed a extruded diet twice a day at the different feeding rates of satiation (100%), 90%, 80% and 70% of satiation for 10 weeks. Mean Water temperature was $19.2{\pm}2.8^{\circ}C$ during the feeding trial. Weight gain and condition factor increased significantly with increase in daily feeding rate (P<0.05), but there was no significant difference in weight gain of fish fed the diet between 100% and 90% of satiation. Survival and feed efficiency were not significantly different among all groups. Proximate composition of dorsal muscle was not significantly affected by feeding rate. Based on the results of this study, optimum feeding rate for growth and condition factor of adult flounder (535-928 g) seemed to be 90% of satiation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.538-543
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• 2020

A feeding trial was conducted to investigate the effect of feeding frequency on the growth performance and body composition of juvenile mandarin fish Siniperca scherzeri. Triplicate groups of fish (initial fish weight, 7.5 g/fish) were fed to apparent satiation at one, two, three or four meals per day for 8 weeks. The results showed that weight gain of fish fed one meal per day was significantly (P<0.05) lower than those fish fed two, three or four meals per day. Feed efficiency of fish fed two meals per day was significantly (P<0.05) higher than other experimental groups. The plasma cholesterol content was significantly lower in fish fed one meal per day than those fed two, three or four meals per day. Consequently, we can conclude that feeding juvenile mandarin fish twice daily to apparent satiation is acceptable and sufficient to achieve good growth and feed efficiency, as fish performance was not remarkably enhanced when feeding increased from two to four times per day.

• Journal of Aquaculture
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• v.22 no.1
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• pp.11-15
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• 2009

Effect of fasting and refeeding on growth and blood chemistry of juvenile olive flounder Paralichthys olivaceus L. was investigated when fish achieved compensatory growth. Fish were fed the experimental diet for 6 days a week. Five treatments in triplicate were prepared: C, S1, S2, S3 and S4. Fish in the control group (C) were hand-fed to apparent satiation twice a day. Fish in treatments of S1, S2, S3 and S4 experienced 1, 2, 3 and 4 weeks of starvation and were then hand-fed to satiation twice daily during the remaining 7, 6, 5 and 4 weeks of the experiment, respectively. Weight gain of fish in C, S1 and S2 were higher than those of fish in S3 and S4. A significant difference in plasma total protein, glucose, triglyceride, $T_3$ and $T_4$ was observed in between starved and refed fish for the rest periods of the feeding trial. Plasma total protein and $T_3$ of flounder decreased with week of fasting and following correlationships were obtained; Y (Total protein) = -0.13X (week of fasting) + 1.54, $R^2=0.9792$ and $Y(T_3)=-11.48X$ (week of fasting) + 79.57, $R^2=0.8822$, respectively.

• Journal of Aquaculture
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• v.1 no.1
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• pp.1-11
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• 1988

There are many problems to be solved for the establishment of more feasible and simplified method of seed production of marine fishes. One of the most important tasks in seed production is to clarify the feeding ecology of larvae and juveniles under. rearing conditions. In the present study, two groups of postlarvae-juveniles of the flounder, Paralichthys olivaceus were used. One ranging 11.38 to 17.08 mm in mean total length was fed with Artemia nauplii at two different water temperatures (19 to $21^{\circ}C$ and 24 to $25^{\circ}C$) and the other ranging 4.39 to 10.64 cm in mean total length was fed with prepared diet. Time required from the start of feeding to satiation was 45 to 55 minutes at 24 to $25^{\circ}C$ and nearly one hour at 19 to $21^{\circ}C$. Mean numbers of Artemia nauplii in digestive tract were 236 to 375 individuals per fish at 24 to $25^{\circ}C$. The amount of food remained in the intestine was $24.8\%$ of the total food in the digestive tract. In juveniles of 4.39 to 10.64 cm in mean total length, amount of prepared diet consumed at satiation was 0.04 to 0.46 g per fish. Digestive tract index in juveniles was rapidly decreased for 24 hours after satiation and kept nearly constant after 48 hours, showing that the time to completely digest the prepared diet in juveniles was estimated to be about 48 hours.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.4
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• pp.399-405
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• 2014

We investigated the effects of feeding rate on the growth performance, blood components, and histology of growing olive flounder Paralichthys olivaceus. Optimum feeding rate (initial fish mean weight : $316.7{\pm}6.18g$) was determined under the optimum water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.4%, 0.6%, and 0.8% of body weight (BW) per day, and to satiation. Feeding trial was conducted using a flow-through system with 10 1.2-metric ton aquaria receiving filtered seawater at $21-24^{\circ}C$ for 3 weeks. Weight gain (WG) and specific growth rate (SGR) were significantly higher in fish fed to satiation (1.0% BW/day) than in those in other treatments. These parameters were negative and significantly lower in the starved fish than in fish fed the experimental diet at all feeding rates. There were no significant differences in WG and SGR among fish fed at 0.4%, 0.6%, and 0.8% BW/day. Hematocrit and hemoglobin in fish fed to satiation were significantly lower than those in other treatments. Histological changes of fish fed at 0.6% BW/day indicated that this group was in the best condition; differences were not found in tissues of fish fed at 0%, 0.6% and 1.0% BW/day. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 317 g was 0.99% BW per day at the optimum water temperature.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.582-587
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• 2014

We investigated the effects of feeding rate on the growth, blood components, and histology of sub-adult olive flounder Paralichthys olivaceus. Optimum feeding rate (initial fish mean weight : $384.2{\pm}5.91g$) was determined under the optimum water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.3%, 0.5%, and 0.7% body weight (BW) per day, and to satiation. The feeding trial was conducted using a flow-through system with ten 1.2-metric ton aquaria receiving filtered seawater at $20-24.5^{\circ}C$ for 3 weeks. After the feeding trial, the weight gain (WG) and specific growth rate (SGR) were significantly higher in fish fed at 0.7% BW/day and those fed to satiation (0.9% BW/day) than in fish fed at other feeding rates or in the unfed fish. These parameters were negative and significantly lower in the unfed fish than in those fed the experimental diet at all feeding rates. There were no significant differences in WG and SGR among fish fed at 0.3 and 0.5% BW/day and among those fed at 0.7% BW/day and to satiation. The histological changes in the hepatopancreas, kidney, and anterior intestine of fish fed at 0, 0.5, and 0.9 % BW/day did not differ much. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 384 g was 0.74% BW per day at the optimum water temperatures.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.1063-1068
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• 2014

We investigated the effects of feeding rate on the growth performance and blood components of sub-adult olive flounder Paralichthys olivaceus. Optimum feeding rate (initial fish mean weight : $370{\pm}5.72g$) was determined under the low water temperature. Two replicated groups of fish were fed a commercial diet at rates of 0%, 0.3%, 0.4%, 0.5%, and 0.6% body weight (BW) per day, and to satiation (0.75%). Feeding trial was conducted under a flow-through system with 12 1.2-metric ton aquaria receiving filtered seawater at $12-14^{\circ}C$ for 4 weeks. Weight gain (WG) and specific growth rate (SGR) for fish fed at 0.6% BW per day was significantly higher than that of unfed fish (0%) and fish fed at 0.3% and 0.4% BW per day. There were no significant differences in WG and SGR among fish fed at 0.5%, 0.6%, and 0.75%. These parameters were negative and significantly lower in the starved fish than in fish fed the experimental diet at all feeding rates. Survival for unfed fish (0%) was significantly lower than that of fish fed at 0.4%, 0.5%, and 0.6%. Hematocrit and hemoglobin content of fish fed at 0% and 0.75% (satiation) were significantly lower than that of fish fed at 0.4% BW per day. Total protein content in unfed fish was significantly lower than those in other treatments. Broken-line regression analysis of weight gain showed that the optimum feeding rate of olive flounder weighing 370 g was 0.51% BW per day at the low water temperature.

• Korean Journal of Environment and Ecology
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• v.29 no.4
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• pp.503-507
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• 2015

To examine the interannual variation of seedfall and seed viability rates of Acer pictum subsp. mono (APSM), we investigated the annual seedfall and seed viability of APSM in the natural broadleaved forest in Mt. Jungwang, Gangwon-do, from 2009 to 2014. The amounts of annual seedfalls from 2009 to 2014 were revealed to be 5,700, 4,060, 60,900, 403,450 and 310 ea/ha respectively. 2013 is presumed to be the masting year since large amounts of seedfall were revealed, compared to that of the other years in the study period. Also, the amount of seeds was significantly different among seed viabilities. Most fallen seeds were damaged or decayed, accounting for 47.88% of the total, followed by empty seeds, undeveloped seeds and sound seeds in that order. The percentage of sound seeds ranged from 6.7 to 31.0%, which marks the lowest average with 16.74%. In the masting year, 2013, a significantly larger number of sound seeds fell at 125,070 ea/ha, on the forest floor than in the other years (320~17,840 ea/ha). Meanwhile, the ratio of damaged or decayed seeds was the lowest at 38%, although the number of those seeds was the largest, 153,310 ea/ha, for the same year. These results imply that the surplus seeds are supplied for natural regeneration in the masting year, supporting the seed predator satiation hypothesis. More long-term researches should be conducted on the seed production of broadleaved trees.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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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.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.55-55
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• 2005