• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1272-1275
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• 2001

Two hundred and forty post-larvae (PL) of fresh water prawn, Macrobrachium rosenbergii were distributed in eight treatment groups with three replicates each. Eight experimental diets were prepared by using squilla (Orato squilla nepa), squid (Sepia pharonis) and clam (katelysia opima) alone or in different combination as source of animal protein and compared to a control diet containing fish meal. Total crude protein content for all dietary treatments was around 32%. Total protein content of fish meal was replaced by an equal amount of protein from different animal protein sources on isonitrogenous basis. Diets were fed at 5% of the body weight of post-larvae twice daily. The experiment was conducted for a period of 60 days. It was found that all the above three protein sources could be used by completely replacing fishmeal except clam meal at higher level of inclusion (26%). A combination of squid and squilla meal at 14% each in the diet increased the growth performance of PL significantly (p<0.05) in terms of Specific growth rate (SGR) % (5.17), FCR (2.12) and PER (1.51). Squilla meal can be used to the maximum level of 38% without any growth depression.

• Fisheries and Aquatic Sciences
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• v.24 no.9
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• pp.311-317
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• 2021

Inclusion effect of various levels of jack mackerel meal (JMM) acting as feed attractants and/or stimulants in diets on the growth, feed consumption, feed utilization and whole body composition of rockfish was investigated. Three hundred juvenile rockfish were randomly allocated into 15 flow-through tanks. Five experimental diets supplemented with JMM at 0%, 1%, 3%, 5%, and 10% at the expense of anchovy meal were prepared and referred to as the JMM0, JMM1, JMM3, JMM5, and JMM10 diets, respectively. Weight gain, specific growth rate (SGR) and feed consumption of fish tended to improve with dietary levels of JMM. The greatest weight gain, SGR and feed consumption were observed in fish fed the JMM10 diet, followed by the JMM5, JMM3, JMM1, and JMM0 diets, in that order. Condition factor (CF) of fish tended to improve with dietary inclusion levels of JMM. Growth performance, feed consumption and CF of fish tended to improve with dietary inclusion levels of JMM ranging from 0% to 10%.

• The Journal of Fisheries Business Administration
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• v.49 no.4
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• pp.19-36
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• 2018

Overstock in aquaculture is a matter of concern in aquaculture management. To sort fish based on fingerling size in case of overstocking is an important problem in aquaculture farm. This study aims to determine the amount of fry overstock and sorting time in aquaculture farm. This study builds a mathematical model that finds the value of decision variables to optimize objective function summing up the fingerling purchasing cost, aquaculture farm operating cost and feeding cost under mortality and farming period constraints. The proposed mathematical model involves following biological and economical variables and coefficients: (1) number of fingerlings, (2) sorting time, (3) fish growth rate and variation, (4) mortality, (5) price of a fry (6) feeding cost, and (7) possible sorting periods. Numerical simulation is presented herein. The objective of numerical simulation is to provide decision makers to analyse and comprehend the proposed model. When extensive biological data about growth function of fry becomes available, the proposed model can be widely applicable to real aquaculture farms.

• Journal of Aquaculture
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• v.14 no.2
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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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.3
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• pp.262-267
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• 2009

Two 15-week feeding trials were conducted to investigate feeding rate and feeding frequency for growth of sub-adult flounder in suboptimal water temperature ($12^{\circ}C$). In the first experiment, duplicated groups of fish (initial mean weight of 279 g) were fed a extruded pellet once a day at the different feeding rates of 0.1, 0.15, 0.2, 0.3% body weight per day (BW/d), and satiation (0.32% BW/d). Weight gain and feed efficiency were increased significantly (P<0.05) with increase in feeding rates from 0.1 to 0.3% BW/d, but there were no significant differences in weight gain and feed efficiency of fish fed the diet between 0.3% BW/d and to satiation. Crude protein content of dorsal muscle of fish fed the 0.1% BW/d diet was significantly (P<0.05) lower than that of the other groups. In the second experiment, duplicated groups of fish (initial mean weight of 281 g) were fed to apparent satiation with a extruded pellet at three different feeding frequencies (one meal every two days, one meal a day and two meals a day). Weight gain, feed efficiency and condition factor of fish fed one meal every two days were significantly (P<0.05) lower than those of fish fed one meal and two meals a day, but there were no significant differences in weight gain, feed efficiency and condition factor of fish fed between one meal and two meals a day. Based on the results of this study, optimum feeding frequency is one meal a day with satiation feeding for growth and feed efficiency of sub-adult flounder (270-350 g) in suboptimal water temperature ($12^{\circ}C$).

• Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.24.1-24.6
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• 2016

We determined the optimum dietary protein level in juvenile barred knifejaw Oplegnathus fasciatus in cages. Five semi-purified isocaloric diets were formulated with white fish meal and casein-based diets to contain 35, 40, 45, 50, and 60 % crude protein (CP). Fish with an initial body weight of $7.1{\pm}0.06g$ ($mean{\pm}SD$) were randomly distributed into 15 net cages (each size: $60cm{\times}40cm{\times}90cm$, $W{\times}L{\times}H$) as groups of 20 fish in triplicates. The fish were fed at apparent satiation level twice a day. After 8 weeks of feeding, the weight gain (WG) of fish fed 45, 50, and 60 % CP diets were significantly higher than those of fish fed 35 and 40 % CP diets. However, there were no significant differences in WG among fish fed 45, 50, and 60 % CP diets. Generally, feed efficiency (FE) and specific growth rate (SGR) showed a similar trend as WG. However, the protein efficiency ratio (PER) was inversely related to dietary protein levels. Energy retention efficiency increased with the increase of dietary protein levels by protein sparing from non-protein energy sources. Blood hematocrit content was not affected by dietary protein levels. However, a significantly lower amount of hemoglobin was found in fish fed 35 % CP than in fish fed 40, 45, 50, and 60 % CP diets. Fish fed 60 % CP showed the lowest survival rate than the fish fed 35, 40, 45, and 50 % CP diets. Broken-line analysis of WG showed the optimum dietary protein level was 45.2 % with 18.8 kJ/g diet for juvenile barred knifejaw. This study has potential implication for the successful cage culture of barred knifejaw.

• 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.50 no.4
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• pp.429-436
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• 2017

The seasonal and interannual variations in fish assemblages in the coastal waters off Gijang were examined with an otter trawl from 2015 to 2016. A total of 59 fish species was collected during the study period. The dominant species were Caelorinchus multispinulosus, Clupea pallasii pallasii and Chelidonichthys spinosus. Seasonal changes in fish assemblages appeared to be distinct in the study area. The fish assemblages in summer and autumn were clearly distinguishable from those in other seasons, and the largest numbers of species and individuals were captured in winter and summer, respectively. Because fish assemblages are closely related to changes in water temperature, long-term changes in water temperature can have a significant impact on the productivity of offshore fisheries by changing fish species composition, habitat migration, and growth rate of fish.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.12
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• pp.1769-1775
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• 2006

An eight week feeding trial was conducted to investigate the effects of dietary supplementation of hizikia (Hizikia fusiformis) on growth performance, immune responses and resistance of juvenile olive flounder (Paralichthys olivaceus) to Streptococcus iniae. Four experimental diets (designated as Hiz 0, Hiz 2, Hiz 4 and Hiz 6) were formulated to be isonitrogenous (50% crude protein) and isocaloric (17.2 MJ/kg DM). Hizikia powder was added at 0%, 2%, 4% and 6% in diets Hiz 0, Hiz 2, Hiz 4 and Hiz 6, respectively. Three replicates of fish groups (15 fish/tank) were fed one of the experimental diets. At the end of feeding trial, no significant differences were observed in final body weight, specific growth rate, protein efficiency ratio, feed utilization and feed intake among fish groups fed the experimental diets. However, there was clear trend that the growth performances of fish were improved by the increment of dietary hizikia showing a positive growth effects. Mean phagocytes activated with nitro-blue-tetrazolium were significantly increased with the increment of dietary hizikia. The cumulative mortality was significantly (p<0.05) lower in the fish groups fed Hiz 6 diet (no mortality) than that in the other fish groups for 15 days of S. iniae challenge test. The findings of this study suggest that a dietary supplementation of hizikia could enhance the nonspecific immune response and improve the resistance of juvenile olive flounder to S. iniae.

• Journal of fish pathology
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• v.26 no.3
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• pp.219-229
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• 2013

Experiments were carried out to investigate the growth and hematological parameters of rock bream Oplegnathus fasciatus exposed to several different concentrations (0, 1, 2, 4, $8{\mu}g/L$) of tributyltin (TBT) for 4 weeks. Growth rate of the fish exposed to $8{\mu}g/L$ of TBT concentration was significantly lower than that of control group fish. The major hematological findings were significant decreases in the red blood cell count, hematocrit value and hemogobin concentration in the fish exposed to $8{\mu}g/L$. Although serum glucose concentration was significantly reduced compared to the control group, total protein concentration was found to be significantly increased over the control group. Exposure to $8{\mu}g/L$ of TBT concentration resulted in significant increase in the enzyme activities, such as glutamic oxalate transminase and glutamic pyruvate transminase in the fish. The present findings suggest that exposure to $8{\mu}g/L$ concentration of TBT can cause significant changes in growth and hematological parameters of rock bream Oplegnathus fasciatuso.