• 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 Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.197-205
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• 1984

From 1981 to 1982, a series of experiments on the optimum growth temperature, wintering temperature and lethal minimum temperature of the walking catfish Clarias batrachus, of about 12 to 40 g yearlings, were carried out using indoor recirculating aquariums at water temperature between $14^{\circ}C\;and\;34^{\circ}C$. The results are as follows. The optimum temperature of this species was turned out to be approximately $25^{\circ}C$ with highest feed intake and growth rates, and lowest conversion rate than at any other temperatures. The minimum temperature at which the fish can show growth turned out to be $18^{\circ}C$, At this temperature daily growth rate for 62 days was about $0.1\%$ and all fish survived. When this species was kept at $16^{\circ}C$ or lower, no fish survived more than one month and at lower than $14^{\circ}C$ all fish died out in 1 to 7 days. In accordance with these results it could be inferred that $18^{\circ}C$ is the minimum wintering temperature. Rearing this species at the minimum growth temperature for a long time, for wintering for instance, the sudden change of water temperature, especially decreasing to lower than $15^{\circ}C$ can be lethal for all fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.581-585
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• 1986

A growth experiment of the Israeli strain of common carp (Cyprinus carpio) under varying dissolved oxygen levels in the recirculating water system was conducted at the Fish Culture Experiment Station of the National Fisheries University of Pusan from August 28, 1985 to September 17, 1985. Five tanks with a capacity of $5m^3$ of water each were used under the same condition of water parameters except for dissolved oxygen levels which were designed to maintain at 2.0, 2.5, 3.0, 3.5 and 4.0 mg/l ranges. The weight of fish in the beginning was about 300g and each tank was stocked with 200kg of fish. DO level of 3.5mg/l was found to be the best level with a feed coefficient of 1.57 and a daily growth rate of $1.411\%$ whereas 4.mg/l showed a slightly decreased performance of 1.63 and $1.365\%$ respectively. The amounts of feed consumed in 3.5 and 4.0mg/l DO levels were almost the same. Below 3.0mg/l DO levels the growth rate markedly decreased. Furthermore, in 2.0 and 2.5 mg/l groups, the fish did not accept feed vigorously and after feeding the fish usually concentrated around the inflow point showing oxygen deficiency response, The experiment indicates that the DO range of 3.5 to 4.0mg/l is the optimum level for the best growth at $27.5^{\circ}C$. DO concentration above these levels is considered a waste of energy resulting in uneconomical performance, and on the other hand, below these levels, the carp certainly shows a poor growth performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.312-320
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• 2021

In this study, we aimed to develop a feed additive that can promote the growth of stone flounder (Kareius bicoloratus). To this end, we fermented mealworm medium (5%, w/v) with lactic acid bacteria (LAB) with antibacterial function (HeTm_LpWpPa) and evaluated its efficacy as a feed additive. Fish (approximately 5-6 g) were reared in six completely recirculating tanks (100 fish/tank) for 6 weeks. The total length of fish with and without HeTm_LpWpPa supplementation was 8.26 and 8.42 cm and body weight was 19.71 and 20.28 g, respectively, at 6 weeks. The weight gain of the control and experimental groups was 223.26 % and 248.76 %, respectively. The specific growth rate at 6 weeks was 2.79 % (control) and 2.98% (experimental), and the growth rate of the experimental group was slightly higher (0.19 %) than that of the control group. At the end of the experiment (i.e. 6 weeks), the number of fish below the mean weight in the experimental group was 3 (1 %) and that in the control group was 17 (5.7 %). These results indicate that feed supplementation of 10 % HeTm_LpWpPa could be utilized to promote the growth of flounder in farming.

• Proceedings of the Korean Nutrition Society Conference
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• 2003.05a
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• pp.301.1-301.1
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• 2003

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.6
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• pp.868-872
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• 2008

This experiment was conducted to evaluate the long term effects of dehulled soybean meal (DHSM) as fish meal (FM) replacer in the diet for olive flounder, Paralichthys olivaceus, for 42 wk at a commercial fish farm. The four experimental diets were MP (moist pellet based on raw fish), $DHSM_0$ (fish meal based dry pellet), $DHSM_{30}$ (30% fish meal was replaced by DHSM) and COMD (commercial dry pellet). Fish were fed one of the four diets containing 50% crude protein and 16.7 kJ available energy/kg diet for 42 wk. Fish averaging $3.20{\pm}0.04g$ ($mean{\pm}SD$) were initially distributed to each tank as a group of 6,000 fish reared in a flow-through system. At the end of the experiment, average body weight of fish was $315{\pm}9.3g$ ($mean{\pm}SD$) ). Weight gain (WG) and feed efficiency (FE) of fish fed MP, DHSM0 and DHSM30 showed no significant difference among the diet treatments. However, WG and FE of fish fed MP were significantly higher than those of fish fed COMD (p<0.05). Specific growth rate (SGR), protein efficiency ratio (PER) and survival of fish fed all diets were not significantly different among the dietary treatments. Therefore, these results indicate that DHSM could replace up to 30% white fish meal with amino acid supplementation in olive flounder diets for long-term feeding practice at the commercial farm.

• Fisheries and Aquatic Sciences
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• v.11 no.1
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• pp.15-22
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• 2008

Excessive growth of phytoplankton is a common and severe problem in intensively farmed pangasiid catfish (Pangasius hypophthalmus) culture ponds. It can lead to cyanobacterial blooms, reduced fish growth, bad-tasting fish flesh, and lower market demand. To investigate how to manage undesirable phytoplankton growth, we evaluated three stocking strategies in nine rural fishponds (0.020-0.022 ha) owned by various farmers: a pangasiid catfish mono culture (treatment 1, $T_1$), and pangasiid catfish-silver carp (Hypophthalmichthys molitrix) polycultures at two stocking ratios of 1:1 (treatment 2, $T_2$) and 2:1 (treatment 3, $T_3$). The total density of all ponds was approximately 30,000 fishes/ha. Monoculture ($T_1$) resulted in significantly higher (p < 0.05) nutrient levels (nitrate and phosphate) in ponds than did polyculture ($T_2$ and $T_3$). Nutrient loads increased with culture time, resulting in increased growth of phytoplankton, including Cyanophyceae (9 genera), Chlorophyceae (15 genera), Bacillariophyceae (8 genera), and Euglenophyceae (3 genera). The introduction of silver carp as a co-species helped to regulate phytoplankton growth and to improve the water quality of pangasiid catfish culture ponds.

• Journal of Aquaculture
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• v.18 no.1
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• pp.37-44
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• 2005

This study was conducted to compare the physiological conditions of black porgy (Acanthopagrus schlegeli) when reared in freshwater (0 psu) and seawater (35 psu) during 90 days. In terms of stress response, there was no significant difference in cortisol levels of the fish reared either freshwater or seawater until 60 days. Although cortisol level of fish reared in freshwater(12.6$\pm$5.0 ng/ml) was significantly higher than in seawater (4.5$\pm$2.9 ng/ml) at the end of experiment, these values were stable levels as compared with that of non-stressed fish. No significant differences in plasma osmolalities were recognized between the fish reared in freshwater (346.7$\pm$4.6$\~$356.5$\pm$2.1 mOsm/kg) and seawater (350.0$\pm$2.0$\~$357.0$\pm$22.6 mOsm/kg). Normal structure of gill lamellae without histological damage or cell necrosis has been observed in the fish reared in freshwater. In connection with growth and survival rate, total length and body weight of fish reared in freshwater were slightly longer and higher than those of fish reared in seawater. Survival rate of black porgy reared in freshwater was slightly higher than that of fish reared in seawater, but there was no significant difference. The results suggest that black porgy is reared with normal growth rate in freshwater without stress.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.2
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• pp.390-398
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• 2015

A feeding experiment was conducted to determine the use of distillers dried grain (DDG) as a partial replacement for fish meal in the diet for juvenile rockfish, Sebastes schlegeli. Four iso-nitrogenous (50% crude protein) and iso-caloric (4.3 kcal/g) diets (designated as DDG0, DDG7, DDG14, and DDG21) were formulated to contain 0, 7, 14, and 21% DDG. Triplicate groups of juvenile rockfish (initial body weight, $10.2{\pm}0.2g$) were fed one of the experimental diets to visual satiety twice a day (09:00 and 17:00) for 8 weeks. At the end of the feeding trial, survival of rockfish was above 97% and not affected by dietary DDG levels (P>0.05). Weight gain, feed efficiency and daily feed intake of juvenile rockfish were significantly decreased with increase of dietary DDG levels (P<0.05). Condition factor, hepatosomatic index and visceralsomatic index of juvenile rockfish were not significantly affected by dietary DDG levels (P>0.05). No significant differences were observed in the contents of moisture, crude protein, crude lipid and ash of the whole body and dorsal muscle in juvenile rockfish fed the experimental diets (P>0.05). Therefore dietary inclusion of DDG as a replacement for fish meal could depress the growth of juvenile rockfish.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.5
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• pp.959-966
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• 2020

With the growing importance of the fishery industry and the rapid growth of the aquaculture industry, research on smart farms through ICT convergence in the aquaculture field is in progress. To enable monitoring of the growing environment at the farm site, an underwater drone drive unit, an image collection device, an integrated controller for posture stabilization, and a remote control device capable of controlling and controlling drones through real-time underwater images were proposed, and design, development, and tests were conducted. By utilizing underwater drones, it is possible to replace the supply and demand of manpower and high-cost work in the aquaculture industry, and to manage fish farms in a stable manner by reducing the probability of farming deaths.