• The Journal of Fisheries Business Administration
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• v.48 no.3
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• pp.47-59
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• 2017

Fish mortality is the most important success factor in aquaculture management. To order fingerlings considering the effect of mortality is a important problem in aquaculture farm. This study is aimed to decision the number and size of fry in aquaculture farm. This study build the mathematical model that finds the value of decision variable to minimize total cost that sums up the fingerling purchasing cost, aquaculture farm operating cost and feeding cost under mortality constraint. The proposed mathematical model involve biological and economical variables: (1) number of fingerlings (2) fish growth rate (3) mortality (4) price of a fry (5) feeding cost, and (6) possible order period. Numerical simulation model presented here in. The objective of numerical simulation is to provide for decision makers to analyse and comprehend the proposed model. When extensive biological and cost data become available, the proposed model can be widely applied to yield more accurate results.

• The Journal of Fisheries Business Administration
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• v.47 no.4
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• pp.1-13
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• 2016

Fish mortality is the most important success factor in aquaculture management. To analyze the effect of mortality considering biological and economic condition is a important problem in land-based aquaculture. This study is aimed to analyze the effect of mortality for duration of cultivation in land-based aquaculture. This study builds the mathematical model that finds the value of decision variable to minimize cost that sums up the water pool usage cost, sorting cost, fingerling cost and feeding cost under critical standing corp constraint. The proposed mathematical model involves many aspects, both biological and economical: (1) number of fingerlings (2) timing and number of batch splitting event, based on (3) fish growth rate, (4) mortality, and (5) several farming expense. Numerical simulation model presented here in. The objective of numerical simulation is to provide for decision makers to analyse and comprehend the proposed model. When extensive biological and cost data become available, the proposed model can be widely applied to yield more accurate results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.5
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• pp.380-384
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• 2004

The toxic impact of parathion on bagrid catfish (Pseudobagrus fulvidraco) juvenile was examined 96 hr $LC_{50}$ value of parathion estimated as 1 90 mg/L. Chronically, bagrid catfish were exposed for 30 days to concentrations of parathion, i.e. 63, 95, 190 and $380\;{\mu}g/L$, representing 3.3, 5.0, 10.0 and $20.0{\%}$ of the 96 hr $LC_{50}$. Survival rate was significantly affected by the concentration over $63\;{\mu}g/L$ after 10 days. Growth rate, specific growth rate (SGR) and feed efficiency were reduced in time as concentration dependent manner. Growth rates of the exposed groups were significantly reduced as $28.06-60.63{\%}$ to the control fish, SGR was decresed as $1.50-4.72{\%}$ and feed efficiency was declined as $6.10-11.90{\%}$. It can be concluded that if p. lulvidraco is chronically exposed to parathion over $63\;{\mu}g/L$ concentration, the physiological damages might affect growth factors of the fish.

• Journal of Aquaculture
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• v.11 no.3
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• pp.363-369
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• 1998

The effects of feeding frequency on growth and body composition of juvenile chum salmon (Oncorhynchus keta) were compared among five groups at different feeding frequencies : 4 times daily, 2 times daily, once a day, 4 times every other day, and 2 times every other day. The effects of 1~2 nonfeeding days per week were also examined. Growth rates, feed efficiencies, survival rates, and condition factors of fish fed twice and 4 times daily were higher than for the other groups, and were also higher for fish fed 6~7 days per week than those fed 5 days per week. Hepatocyte nuclei of fish were larger in the daily feeding groups than others, which suggested fish daily fed would have higher methabolic rate. Theses results suggested that captive juvenile chum salmon should be fed 2 or more times per day, and 6~7 days per week.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.4
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• pp.248-252
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• 2008

A 6-week feeding trial was conducted to investigate effects of dietary supplementation with wood vinegar (WV) as a feed additive for juvenile olive flounder, Paralichthys olivaceus. Eight experimental diets supplemented with 0(control), 0.01, 0.025, 0.05, 0.1, 0.25, 0.5 and 2.0% WV/kg diet($WV_0,\;WV_{0.01},\;WV_{0.025},\;WV_{0.05},\;WV_{0.1},\;WV_{0.25},\;WV_{0.5},\;and\;WV_{2.0}$, respectively) were prepared by mixing with basal diet. After the 6-week feeding trial, fish fed the $WV_{0.1}$ diet had significantly higher weight gain, feed efficiency, and specific growth rate than those of fish fed the other diets(P<0.05). No mortality was observed in the treatment groups fed the experimental diets for 6 weeks. The liver antioxidant activity of fish fed the $WV_{0.01},\;WV_{0.025},\;and\;WV_{0.05}$ diets was significantly higher than that of fish fed the other diets. The lysozyme activity of fish fed the $WV_{0.25}$ diet was significantly higher than that of fish fed the other diets. Fish fed diets supplemented with WV had significantly lower cumulative mortality than that of fish fed the control diet throughout the challenge test, and fish fed the $WV_{0.05}\;and\;WV_{0.1}$ diets had the highest resistance to disease caused by Edwardsiella tarda at day 7 of the challenge test. Therefore, feeding 0.05-0.1% WV/kg diet improves the growth and immune responses of juvenile olive flounder, Paralichthys olivaceus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.233-238
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• 1981

A recirculating water system without filter bed was used for a high density experimental rearing of common carp, Cyprinus carpio, during the summer of 1981. Of the water system, 3 tanks were used for stocking each tank with 10,000, 20,000 and 30,000 common carp fingerlings which averaged 0.6 g. The water in the system was maintained in dark green colour by heavy growth of phytoplankton during the most period of the experiment. In this experiment, the best daily growth rate, $3.7\%$, was obtained from the 10,000 fish group followed by $2.8\%\;and\;3.0\%$ from the 20,000 and 30,000 fish groups respectively. Thus there was no significant difference between the latter two groups. Especially, notably high concentration of total ammonia, $5\sim7$ ppm ammonia-N, in the culture water appeared during the most experimental period, but this did not seem to have affected feeding and growth of the fish when the water was kept at heavy bloom. It was also obvious that the outbreak of columnaris disease was effectively depressed in this green water recirculating system compared to that in clarified recirculating system. One tank ($7m^2$) of this system was stocked with 446 common carp of intermediate size averaging 352.2 g and after 40 day rearing they grew to 486.3 g in average with a daily growth rate of $0.8\%$. This result was a little inferior to that reared in a tank of the clarified water system as control which showed $1.0\%$ daily growth rate. Therefore, before an initiation of the commercial production of fish in this method, further studies concerning the amount of ammonium with its effect on the fish under rearing in this system and the columnaris disease problem should be carried out.

• Journal of Aquaculture
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• v.18 no.2
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• pp.98-106
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• 2005

A feeding trial of two extruded pellets (EPI, 45% crude protein with 7% crude lipid and EP2, 47% crude protein with 10% crude lipid)${\times}$ two satiation rates (satiation and 80% satiation)${\times}$ three feeding frequencies (three, two and one meal a day) factorial design with three replications was carried out to investigate the optimum feeding frequency and satiation rate for growth of juvenile flounder. Flounder averaging 55 g were fed a extruded pellets for 58 days. Daily feed intake was affected by dietary composition, feeding frequency and satiation rate (P<0.05). Weight gain of fish fed the EP1 and EP2 was not affected by both dietary composition and feeding frequency (P>0.05), but affected by feeding satiation rate (P<0.05). Weight gain of fish fed the each of EP1 and EP2 twice daily with satiation was the highest among treatments, but was not significantly different to that of fish fed the diets three times daily with satiation feeding. Feed efficiency and protein efficiency ratio of the fish were not affected by dietary composition, feeding frequency and satiation rate (P>0.05). Moisture, crude protein and crude lipid contents of the muscle of fish were affected by satiation rate. Moisture and crude protein contents of the liver were affected by dietary composition. Based on fish performance results, it can be concluded that the proper feeding frequency for the growth of juvenile flounder grown from 55 g to 90 g is two meals a day with satiation feeding, regardless of dietary composition used in this study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.411-417
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• 2021

By-products produced from medicinal plants (MP) were evaluated as feed additives on growth performance, blood chemistry, and immune responses of the juvenile red lip mullet Liza haematocheila. A commercial diet was used as the control. Four experimental diets were prepared by combining 0.5% of MPs such as Panax ginseng (PG), Schisandra chinensis (SC), Angelica gigas (AG), and Rehmannia glutinosa (RG), via water absorption, to the control diet. Triplicate groups of fish averaging 61.8 g were fed one of experimental diets to apparent satiation for 8 weeks. Dietary supplementation of MPs did not affect the growth performance, biological indices and whole body composition of fish compared to the control. The fish fed with AG diet had an increased weight gain, and specific growth rate compared to fish in SC group. Decreased level of plasma glucose was observed in fish fed diet containing MPs. Lysozyme activity was significantly increased in the fish fed AG diet compared to that of fish in PG group. These results indicate that dietary supplementation of Angelica gigas may enhance growth performance and immune responses in juvenile red lip mullet.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.1
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• pp.87-91
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• 2019

Effects of feeding frequency on the growth performance of juvenile starry flounder Platichthys stellatus were investigated. One thousand fifty fishes were distributed into 15 of 500-L flow-through tanks. Triplicate groups of were fed experimental diet with five feeding frequency (one meal every two days, one meal a day, two meals a day, three meals a day and four meals a day) for 9 weeks. Weight gain and specific growth rate (SGR) of fish fed two meals a day were higher than those of fish fed one meal 2 days and one meal a day, but not different from those of fish fed three meals a day and four meals a day. Feed consumption of fish fed two meals a day was not different from that of fish fed three meals a day and four meals a day. Feed efficiency (FE) and protein efficiency ratio (PER) of fish fed two meals a day were higher than those of fish fed all other diets, except for three meals a day. These results suggest that the optimal feeding frequency is two meals a day for the optimum growth performance of juvenile starry flounder under the experimental conditions.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.508-514
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• 2010

This study was conducted to evaluate the effects of dietary arachidonic acid (AA, 20:4n-6) levels on growth performance and body composition in juvenile eel, Anguilla japonica. Six semi-purified experimental diets were formulated to be isonitrogenous and iso-caloric containing 55.0% crude protein and 15% crude lipid (18.3 kJ of available energy $g^{-1}$). Six different levels of AA were added to the basal diet, with 0, 0.2, 0.4, 0.6, 0.8 or 1.2% on a dry matter (DM) basis, respectively ($AA_{0.07},\;AA_{0.22},\;AA_{0.43},\;AA_{0.57},\;AA_{0.78}\;or\;AA_{1.23}$). After a conditioning period, fish initially averaging 27${\pm}$0.5 g (mean${\pm}$SD) were randomly distributed into each aquarium as triplicate groups of 20 fish each. One of six experimental diets was fed on a DM basis to fish in three randomly selected aquaria at a rate of 2-3% of total body weight twice a day. At the end of the 12-week feeding trial, weight gain (WG) and feed efficiency (FE) of fish fed $AA_{0.78}$ and $AA_{1.23}$ diets were significantly higher than of fish fed $AA_{0.07},\;AA_{0.22},\;AA_{0.43}$ diets (p<0.05). Specific growth rate (SGR) of fish fed the $AA_{0.78}$ diet was significantly higher than of fish fed $AA_{0.07},\;AA_{0.22},\;AA_{0.43}$ diets (p<0.05). However, there were no significant differences in WG, SGR and FE among fish fed $AA_{0.57},\;AA_{0.78}\;or\;AA_{1.23}$ diets (p>0.05). Whole body AA deposition of fish fed the $AA_{1.23}$ diet was significantly higher than for the other diets (p<0.05). Broken-line model analysis on the basis of WG and SGR indicated that the dietary AA requirement could be greater than 0.69% but less than 0.71% of the diet in juvenile eel. The growth-promoting activity of AA observed in the present study provides strong support for the contention that dietary AA is essential for juvenile eel.