• Journal of Fisheries and Marine Sciences Education
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• v.26 no.1
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• pp.72-80
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• 2014

Oxygen consumption (OC) of male black porgy Acanthopagrus schlegelii reared in freshwater (BFW) and seawater (BSW) during the reproductive period was $165.4{\pm}11.0$, $77.6{\pm}8.0$ mg $O_2/kg/h$ at $15^{\circ}C$, $186.2{\pm}13.1$, $133.4{\pm}6.7$ mg $O_2/kg/h$ at $20^{\circ}C$ and $267.9{\pm}19.1$, $198.6{\pm}8.3$ mg $O_2/kg/h$ at $25^{\circ}C$, respectively. During the non-reproductive period, it was shown as $174.0{\pm}7.0$, $85.6{\pm}5.5$ mg $O_2/kg/h$ at $15^{\circ}C$, $200.6{\pm}11.1$, $119.2{\pm}8.7$ mg $O_2/kg/h$ at $20^{\circ}C$ and $271.1{\pm}7.5$, $194.7{\pm}16.7$ mg $O_2/kg/h$ at $25^{\circ}C$, respectively. Thus, OC of BFW was higher than BSW both for non-reproductive and reproductive period. Also, OC increased in proportion to the rise in water temperature, and there was no difference of OC between BFW and BSW at each water temperature during the reproductive or non-reproductive period. OC of BFW and BSW showed clear circadian rhythms on photic conditions of reproductive and non-reproductive period, and the fish consumed more oxygen during the dark phase than for the light phase. In particular, OC of BFW during the reproductive period increased more sharply compared to non-reproductive period when the increase of water temperature was accompanied by the shift from dark to light phase. This implies that they react to the light more sensitively for reproductive period than for non-reproductive period.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.3
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• pp.213-219
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• 1995

The author carried out an experiment to find out the response of Black porgy, Acanthopagrus schlegelii [Bleeker] to the color lights. The experimental tank ($360L{\times}50W{\times}55H$cm) was set up in a dark room. Six longitudinal sections with 60cm intervals are marked in the tank to observe the location of the fish. Water depth in the tank was kept 50cm level. Light bulbs of 20 W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity was controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in order of blue, yellow, white and red in the day-time and blue, red, yellow and white at night. The difference of the average distribution on two different colors of light was 7.18%(0.35-19.55%), and the difference in the daytime(8.20%) was larger than at night (6.15%). The gathering rate of fish on illumination period didn't show the regular trend of increase and decrease, and was fluctuated with instability. The difference of the gathering rate on two different colors of light wasn't distinct, and the difference in the daytime was larger than at night.

• Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.75-84
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• 2014

To determine a suitable dietary protein/lipid (CP/CL) ratio in the early juvenile stages of hybrid porgy ($F_1$), female red sea bream (RSB) ${\times}$ male black sea bream, five diets with various CP/CL ratios-60/7, 55/12, 51/17, 46/23, and 41/28-were prepared and provided to juveniles in triplicate. At the smaller juvenile stage, $F_1$, weighing 0.32 g, a significantly higher specific growth rate (SGR) and feed efficiency (FE) were seen with 60/7 and 55/12 diets. However, in RSB weighing 0.26 g, SGR and FE were higher with the 60/7 diet than the other diets at $21^{\circ}C$. At the larger juvenile stage, $F_1$, weighing 3.7 g, there was no significant difference in SGR or FE among the diets, but RSB weighing 4.0 g fed 60/7, 55/12, and 51/17 diets had higher SGR and FE than 46/23 and 41/28 diets at $24^{\circ}C$. Moreover, survival and apparent nutrient retention of $F_1$ at both stages were significantly higher than those in RSB. These results indicate that both $F_1$ and RSB weighing ca. 0.3 g require a higher dietary CP/CL than those weighing ca. 4 g. Additionally, $F_1$ in both trials showed the suitability of a lower dietary CP/CL than RSB, indicating that mass production of $F_1$ juveniles will be more economical than RSB.

• Journal of Food Hygiene and Safety
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• v.20 no.4
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• pp.205-210
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• 2005

The content of the trace metals in the cultured and wild fishes were determined. The tested fishes were genuin porgy (Pagrus major) and black porgy (Acanthopogrus schlegeli). The samples of the cultured and wild fishes were collected from slices of raw fish in shops, during 2003 to 2004. The samples were digested with acids, then analyzed by ICP (inductively Coupled plasma Spectrometer) and AAS (Automic Absorption Spectrometer) for the content of lead (Pb), cadmium (Cd), arsenic (As), copper (Cu), manganese (Mn) and zinc (Zn). The content of mercury (Hg) was determined using mercury analyzer. The mean contents of trace metals in cultured and wild fish was 0.031,0.047mg/kg far total-mercury,0.321,0.407 for Pb, 0.048,0.063 for Cd, 1.006, 1.132 for As, 0.467,0.806 for Cu, 0.233, 0.293 for Cr, 9.69, 12.20 for Zn,0.798, 0.624 mg/kg far Mn, respectively. The content of all the trace metals except manganese in wild fish was more than that in cultured fish. The highest level of total-mercury, lead, cadmium, zinc, chromium and arsenic in the samples analyzed were all below the quarantine limit of Korean regulation and guideline established by the U.S. Food and Drug Administration f3r human consumption. The level of the trace metals in the samples was negligible, which could be endogenous. Our data obtained in this study showed that the average weekly intakes of lead, cadmium and mercury from cultured and wild fishes takes about $6\∼13\%$ of Un(Provisional Tolerance Weekley Intakes) that FAO/WHO Joint Food Additive and Contaminants Committee has set to evaluate their safeties.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.6
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• pp.379-384
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• 2005

A high-performance liquid chromatography assay method for oxolinic acid in fish products was developed, evaluated and validated through the monitoring of oxolinic acid based on farming and distribution. The recovery rate of the developed method was $102.3-106.7\%$ as compared to conventional methods. The stock solution was stable for 3 weeks under refrigerated condition at $4^{\circ}C$ The performance limit was evaluated as 0.01ppm of oxolinic acid in fish muscle. 478 fish samples such as olive flounder, genuine porgy, common sea bass and black rock fish collected from fish farms in the coastal area from September 2001 to October 2004 were analyzed to evaluate overall efficiency of the modified method and to monitor the actual condition of oxolinic acid usage in fish farm. According to the monitoring results, the modified method was suitable for analysis of oxolinic acid in fish muscle and oxolinic acid might be used in a small portion of fish farms. The suggested analysis method of oxolinic acid was registered in the Korean Official Methods of Food Analysis and is being utilized for fishery products by the Korea Food and Drug Adminstration and the National Fisheries Products Quality Inspection Service.

• Korean Journal of Ichthyology
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• v.17 no.2
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• pp.142-147
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• 2005

To research changes in the fish community of intertidal zones in relation to the construction of the Saemangeum tidal embankment, fishes were collected in the tide pools of Naechodo, Gunsan-si, and of Haechang, Buan-gun in Jeollabuk-do, every month from December 2002 to October 2004. Based on the fishes collected and data from previous studies show that in the tide pools of Haechang, the number of species decreased, and the dominant species is Tridentiger trigonocephalus, as before. However, in the tide pools of Naechodo, the number of species decreased, and the dominant species changed from T. trigonocephalus to Synechogobius hasta. Favonigobius gymnauchen, which inhabits sand-beds, decreased remarkably. Meanwhile, in the intertidal zone of Haechang, young black porgy were caught in large quantities, while in the intertidal zone of Naechodo, young Acanthopagrus schlegelii and Lateolabrax japonicus, which had been caught in a large amounts between 1994 and 2000, were not caught. The results are thought to show that the intertidal zone of Naechodo, Gunsan-si, had more deposits by tide flats than that of Haechang, Buan-gun, which drastically changed the habitat of its fish community.

• Journal of Aquaculture
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• v.20 no.3
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• pp.199-202
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• 2007

We isolated a 317 bp of partial cDNA for doublesex-and mab-3-related transcription factor-1 (DMRT-1) from the testis of olive flounder, Paralichthys olivaceus using RT-PCR. Based on the multiple sequence alignment, olive flounder DMRT-1 shared relatively high sequence homology (82 to 94%) with orthologues from other teleost species such as Atlantic halibut, Hippoglossus hippoglossus, black porgy, Acanthopagrus schlegeli and rainbow trout, Oncorhynchus mykiss. DMRT-1 mRNA was predominantly expressed in the testis of olive flounder. In our investigation for the effect of testosterone treatment in vivo on induced expression of ovarian DMRT-1 transcript, mRNA levels of DMRT-1 in ovary were significantly up-regulated by testosterone treatments (0.3 or $3.0{\mu}g$ testosterone/g body weight for 12 to 36 hours) as judged by RT-PCR analysis. In overall, transcriptional stimulation of DMRT-1 during treatments was more affected by doses of testosterone than treatment durations. This result strongly suggests that the regulation of DMRT-1 be tissue- and gender-specific in olive flounder, and also provides useful baseline knowledge on the testosterone-mediated regulation in the reproductive physiology of this species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.3
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• pp.179-187
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• 1977

This study intended to investigate the shape of the artificial fish reefs settled in the waters of Seogwipo, and the thronging of fish schools into them. The results obtained are summarized as follows : 1. Two types of artifical fish reef, circularized vertical type which is composed of Cryptomeria branches and parachute type, were put off the coast of Seogwipo at $33^{\circ}14'05'$ N Lat., $126^{\circ}34'40'$ E Long. The setting place is located 0.4 sea-mile away from natural fish reefs, at 25 m in depth. And its sediment is consisted of f. S. and Sh. 2. Maximum velocity of wind drift current was 15.28 cm/sec at 15 m depth. The Current direction was $20.5\%$n in the WSW. 3. Maximum fluid resistance of the circularized vertical type to current and wind waves showed about 890 kg, and the weight of sand bags attached to the fish reef totaling 1,200 kg was enough to sustain fish reef. 4. As maximum fluid resistance of the parachute type to current and wind waves was 106.3 kg, the retaining force of sand bags was enough to sustain the fish reef, but vinyl canvas and expansion materials were so poor that the fish reef was lost by the sea current and wind waves. 5. Sixteen species of fish among 53 usually caught in this area were thronged into the artificial fish reef. The fish catches comprized Porgy (Pagrosomus major) $23\%$, black kook fish (Sebastes (Mebarus) intermis) $13\%$, sand borer (Sillago sihama) $11\%$, Sebastes (Pteropodus) hubbsi $7\%$, and file fish (Monacanthus cirrhifer) $6\%$. According to the submarine observations by fivers, it was confirmed that a lot of fish larvae thronged in the middle part of the fish reefs.