• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.2
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• pp.88-95
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• 2016

Most grid sorting has been used to sort out flatfish in shrimp fisheries, while double grid systems have been tested to separate smaller shrimp. The escape of juvenile red seabream through separating panels made with steel grids or large mesh tested for masking effects in a two-species system. Fish behavior was observed in a circulating water tank. The escape rate was 20% greater with the separating codends than with the normal codend in the single-species experiments. The rates in the two-species experiments were 30% or 20% greater than the single-species rates for the normal or separating codends, respectively. The seabream retention rates in the grid separator codend decreased as rockfish retention increased, possibly due to a threat effect. Conversely, the retention rate of both species increased concurrently in the net separator, possibly due to a masking effect. The escape rates of juvenile red seabream varied by compartment in the mesh separating codend. These results suggest that grid separating codends can be used in the field as towed fishing gear to reduce juvenile catch.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.211-215
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• 1997

Experiments were performed to find out the proper conditions of diluents for the short-tenn storage of sperm of black seabream, Acanthopagrus schlegeli. For milt collection, brood stock was reared in a recirculating seawater system. The following results indicated that short-term storage methods with fresh condition could tie employed in black seabream sperm. When the black seabream's serum was used as a diluent for the fresh storage, sperm activity index (SAI), fertilization rate and survival rate derived the best result in $7\~10\;days$ of storage. pH 7 and 8 showed the highest SAI in the same storage condition. In order to keep high SAI and survival rate of the sperm, addition of 800 ppm neomycine into the diluent revealed the best storage results.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.1
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• pp.50-55
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• 2012

We compared the nutritional requirements of whole larvae of the black seabream Acanthopagrus schlegeli, sweet fish Plecoglossus altivelis, olive flounder Paralichthys olivaeus and rock fish Sebastes schlegeli. The larvae were 20, 30, 14 and 5 DAH (or spawning) of black seabream, sweet fish, olive flounder and rock fish, respectively. Specific ${\alpha}$-amylase activity (mU/mg protein) was highest (8,324.9 mU/mg protein) in rock fish larvae (P<0.05). Specific trypsin-like protease activity was highest (11,330.1 mU/mg protein) in black seabream larvae (P<0.05), which also exhibited the highest activity, 685.5 mU/mg dry weight (P<0.05). The specific activities per mg protein and mg dry weight of black seabream were the highest (187.4 mU/mg protein and 11.3 mU/mg dry weight, respectively) (P<0.05). A/P, P/L and A/L ratios of rock fish were 1.47, 90.3 and 133.1, respectively (P<0.05). We present here basic larval digestive enzymatic nutritional requirement data.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.12
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• pp.1736-1743
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• 2014

This study was designed to test the effects of dietary distillers dried grain (DDG) level on the growth performance, feed utilization, body composition and antioxidant activity of juvenile red seabream (Pagrus major). Six isonitrogenous and isocaloric diets were formulated to contain 0%, 5%, 10%, 15%, 20%, and 25% DDG from rice (designated as DDG0, DDG5, DDG10, DDG15, DDG20, and DDG25), respectively. Juvenile red seabream averaging $10.1{\pm}0.05g$ were randomly distributed into 400-L tanks in a flow through systems. Three replicate groups of fish were fed one of the experimental diets to visual satiation two times a day for 10 weeks. Survival, weight gain, feed efficiency, protein efficiency ratio and hepatosomatic index of fish were not affected by dietary DDG levels (p>0.05). Proximate and amino acid composition of whole body in juvenile red seabream were not affected by dietary DDG levels (p>0.05). Plasma content of total protein, glucose, cholesterol, glutamic-pyruvic transaminase, phospholipid and triglyceride were not affected by dietary DDG levels (p>0.05). 1, 1-Diphenyl-2-picryl-hydrazyl radical and alkyl radical scavenging activities in plasma and liver of fish were not affected by dietary DDG levels (p>0.05). The results of this experiment suggest that DDG has the potential to replace plant origin ingredients such as wheat flour and corn gluten meal and could be used up to 25% in diet without incurring negative effects on the growth performance of juvenile red seabream.

• Journal of Aquaculture
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• v.16 no.4
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• pp.262-266
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• 2003

In order to develop a method for the cryopreservation of fish embryos, the determination of optimal concentrations of dimethyl sulfoxide (DMSO), ethylene glycol and glycerol as individual cryoprotectants was performed by using the early embryos of black seabream, Acanthopagrus schlegeli. Optimal concentrations of cryoprotectants were assessed in terms of effects on mortality, median lethal concentration and hatching rate of embryos. The mortality of black seabream embryos immersed in cryoprotectants was related to the concentrations of cryoprotectants and immersion times. The toxicity to embryos was lower in order of DMSO, < ethylene glycol, < glycerol. The results from the mortality, median lethal concentration and hatching rate evaluations suggest that DMSO was the most effective cryoprotectant for black seabream embryos followed by ethylene glycol, and suitable concentrations of DMSO and ethylene glycol were 2.0∼2.25M and 1.0∼1.78M, respectively, with 20 minutes of immersion time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.3
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• pp.350-357
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• 2021

This study aimed to evaluate how fish meal (FM) replacement in diets with a mixture of animal and plant protein sources affect growth performance, feed utilization, hematological parameters and innate immunity of red seabream Pagrus major. A control FM diet was formulated to contain 65% FM (Con). Two other diets were prepared replacing FM in the control diet with a mixture of protein sources (wheat gluten, soy-protein concentrate, tankage meal, and poultry by-product meal) by 30 and 40% (FM30 and FM40, respectively). Total 300 red seabream (body weight, 77.6±0.3g) were distributed to 12 tanks (300 L) in 4 replicates per diet. The fish were fed the diets to apparent satiation for 19 weeks. After the feeding trial, no significant differences could be observed in growth performance, feed utilization, hematological parameters, innate immunity, and survivals among all the dietary treatments. This long-term feeding trial at low water temperature (13.8-17.5℃) indicates that a proper mixture ratio of wheat gluten, soy protein concentrate, tankage meal, and poultry by-product meal can replace FM up to 40% in red seabream diets.

• Korean Journal of Environmental Biology
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• v.39 no.4
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• pp.495-506
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• 2021

In this study, using a continuous behavior measurement technique, the short-term behavioral responses and tolerance limits of red seabream Pagrus major fingerlings to sudden exposure to low salinity in a controlled environment were observed. The activity of the fingerlings suddenly exposed to 21.4, 17.3, and 9.8 psu increased temporarily at the initial exposure to show irregular swimming behavior, but then recovered a stable activity pattern through rapid salinity adaptation. However, the organisms suddenly exposed to 7.3 and 4.3 psu could not withstand the salinity stress, and their swimming behavior was severely disturbed and all individuals died within 48 hours. The findings suggest that red seabream underwent a temporary salinity stress process at the beginning of the exposure to concentrations of 10.0 psu or higher. At these concentrations, osmotic control was possible within at least 11 hours, so stable metabolic activity was also possible. However, organisms suddenly exposed to concentrations below 5.0 psu exceeded the tolerance to low salinity and the sublethal limit. In red seabream exposed to this concentration range, severe behavioral and metabolic disturbances were observed, and death was observed due to osmotic control failure. In conclusion, a salinity range of 5.0 to 10.0 psu can be predicted to correspond to a concentration range in which the osmotic control ability of the red seabream fingerlings is lost, and sub-lethal reactions occur.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1447-1456
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• 2015

Olive flounder (Paralichthys olivaceus) including red seabream (Pagrus major) and jacopever (Sebastes schlegeli) were known to be suitable characteristics for preparing a processed food because of white meat fish containing low fat in muscle. In this study, the physicochemical properties of olive flounder (46-50 cm of length, 950-1,050 g of weight), red seabream (30-33 cm of length, 1,250-1,350 g of weight) and jacopever (20-23 cm of length, 550-650 g of weight) were studied to obtain a basic data for the development of a new processed food. Head, scale, bone and viscera of each samples were removed, and then grinding with homogenizer before experiment. Moisture content of red seabream is lower than that of olive flounder and jacopever, therefore, crude protein and crude lipid are higher content. Red seabream showed higher redness, yellowess and color difference value than those of olive flounder and jacopever except lightness. The major total amino acid in olive flounder, seabream and jacopever were glutamic acid, lysine and aspartic acid in order. Especially, the highest content of free amino acid was lysine for olive flounder and jacopever and alanine for red seabream. The highest content of mineral in olive flounder, seabream and jacopever was potassium (K) and then phosphorous (P) and sodium (Na) in order. The highest amount of fatty acid in olive flounder, red seabream and jacopever was polyenoic acid in which especially contained 6.8, 7.1 and 6.7% for EPA, and 15.2, 15.2 and 17.1% for DHA, respectively. From the result of sensory evaluation, there was no significant difference in color and odor, but not in taste and texture.

• Fisheries and Aquatic Sciences
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• v.2 no.1
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• pp.93-97
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• 1999

The promoter region of alginate lyase gene (aly) from Pseudomonas sp. W7 was used for the high expression of gilthead seabream (Sparus aurata) growth hormone (GH) gene in Esherichia coli. PCR product encoding the premature segment of the growth hormone. was cloned to the downstream of aly promoter. GH was overexpressed With 46 ammo acid of alginate lyase as fusion protein. GH was immunoreactive and production of GH was repressed with supplementation of $0.4\%$ glucose into culture media.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.5
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• pp.433-439
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• 2004

The movement range and diurnal behavior of red seabream (Chrysophrys major) tagged by the ultrasonic pinger externally were measured by acoustic telemetry techniques in the marine ranch of Tongyeong on 20 March to 30 October, 2003. The movement of fishes was monitored with the radio-acoustic linked positioning (RAP) buoy system and VR2 receivers. The test fishes showed behavior. pattern going to deep waters and returning to shallow waters. They moved gradually to deep waters as time goes by. They had a tendency to move wider range in night-time than day-time. It was found that the test fishes rarely showed a significant response to the artificial reefs.