• Journal of Life Science
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• v.28 no.6
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• pp.639-647
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• 2018

A new heat shock protein 70 was identified in red-spotted grouper (Epinephelus akaara) based on an expression analysis. The cDNA of red-spotted grouper Hsp70 (designated RgHsp70) was cloned by the rapid amplification of cDNA ends (RACE) techniques. The full-length of RgHsp70 cDNA was 2,152 bp, consisting of a 5'-terminal untranslated region (UTR) of 105 bp, a 3'-terminal UTR of 274 bp, and an open reading frame (ORF) of 1,773 bp that encode a polypeptide of 590 amino acids with a theoretical molecular weight of 64.9 kDa and an estimated isoelectric point of 5.2. Multiple alignment and phylogenetic analyses revealed that the RgHsp70 gene shares a high similarity with other Hsp70 fish genes. RgHsp70 contained all three classical Hsp70 family signatures. The results indicated the RgHsp70 is a member of the heat shock protein 70 family. RgHsp70 mRNA was predominately expressed in the liver, with reduced expression noted in the head-kidney tissues. The expression analysis of different water temperatures (21, 18, 15 and $12^{\circ}C$) for sampled livers revealed that expression gradually increased at $12^{\circ}C$ compared to $21^{\circ}C$. In this study, the effects of water temperature lowering on the physiological conditions were investigated, and the results revealed that novel RgHsp70 may be an important molecule involved in stress responses.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.864-875
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• 2015

This study investigated the sanitary characteristics of commercial salted semi-dried convict grouper Epinephelus septemfasciatus (SSD-CG) and longneck croaker Pseudotolithus typus (SSD-LC) and suggested standards for salted semi-dried fish (SSD-F), based on the domestic standards for salted mackerel (Scomber japonicus or kwamegi) and salted dried yellow corvenia (Pseudosciaena manchurica), and sanitary characteristics of commercial SSD-F. For the commercial SSD-CG and SSD-LC, respectively, the moisture content ranged from 64.6-76.1 and 65.7-77.5%, salinity from 2.7-8.2 and 1.5-4.9%, volatile basic nitrogen (VBN) from 22.1-88.2 and 13.5-87.4 mg/100 g, peroxide value (POV) from 17.2-195.0 and 28.5-190.2 mEq/kg, and viable cell counts from 6.1-8.4 and 5.4-7.2 log (CFU/g). No Escherichia coli was detected in six kinds of SSD-CG or three kinds of SSD-LC. The standard for controlling the quality of SSD-F is the moisture content (>68%), salinity (>3%), VBN content (>50 mg/100 g), POV (>60 mEq/kg), viable cell counts (>$10^6$ CFU/g), E. coli (>MPN/100 g), and others. Using the established standards, no commercial SSD-F passed. The chemical, microbial, and other results for commercial SSD-F suggest that provisions for controlling the quality of high-quality SSD-F should be established.

• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.260-266
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• 2016

We determined the morphologic characteristics (body weight and abdomen inflation degree) of the mother fish of sevenband grouper, Epinephelus septemfasciatus producing the healthy eggs. Experimental fish were chosen from the reared fish in the sea cage for 6 years. The fish were divided into four size groups by body weight: 4.0~5.0, 5.0~6.0, and 6.0~7.0 kg and four stages (I~IV) by the abdomen inflation degree. After hormone treatment, we observed the ovulation amount of induced eggs, rate of buoyant, fertilization, embryonic survival, and hatching. Egg and oil globule diameter was measured. In order to observe gonadal development, we calculated gonadosomatic index (GSI) and conducted its historical analysis. The ovulation occurred from all experimental fishes over 5.0 kg. The rate of buoyant, fertilization, and embryonic survival was the highest in 6.0~7.0 kg. Hatching rate was the highest in 5.0~6.0 kg. Stage I and II did not induce ovulation. GSI was $0.31{\pm}0.10%$ in stage I, $0.74{\pm}0.25%$ in stage II, $4.68{\pm}0.40%$ in stage III and $6.86{\pm}0.12%$ in stage IV. The rate of buoyant, fertilization, embryonic survival and hatching was the highest in stage III.

• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.229-238
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• 2016

This study aims to investigate egg quality and amino acid composition of buoyant and non-buoyant eggs and evaluate egg quality of sevenband grouper, Epinephelus septemfasciatus. Amino acid analysis of eggs was conducted to investigate what elements were necessary for the survival and good quality of egg depending on farming condition and different diet. We analyzed amino acid from buoyant eggs and non-buoyant eggs, farming conditions (tank and sea cage), and different dietary conditions (formulated feed, formulated feed+raw fish-based moist pellets, and raw fish-based moist pellets). Egg quality was the best in a sea cage and when raw fish-based moist pellets (MP) were fed. In addition, egg quality with formulated and MP was better than that with formulated feed. As a result of amino acid analysis of eggs, buoyant eggs were containing more free amino acid than non-buoyant eggs. Also, eggs with MP were containing more free amino acid than those with formulated feed and MP. Eggs with mixed formulated feed and MP were containing more free amino acid than formulated feed. In conclusion, amino acid was helpful to improve egg quality, and egg quality can be controlled by farming conditions and feed.

• Journal of Aquaculture
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• v.10 no.4
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• pp.463-472
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• 1997

Floating and hatching rates, size and survival activity index(SAI) of spawned eggs of red spotted grouper, Epinephelus akaara were studied to understand egg qualities during the spawning periods in 1992, 1993 and 1995. The fish spawned from mid-July to mid-August when temperature ranged 23~$28^\circC$. Floating, fertilization and hatching rates were higher in the eggs from early to middle than those from late during the spawning period. SAI ranged 1.8~9.6, and it was closely related to survival rate until mouth operning time (SMOT). Egg diameter decreased gradually with the time of spawning, while diameter of oil globule was constant during the spawning periods. Induced spawnings were carried out with one injection of HCG over 5, 000 IU/kg body weight. Floating, fertilization and hatching rates of the induced spawning eggs were higher than those of untreated ones. Thus, induced spawning method with HCG was recommended for collecting fertilized eggs in bulk. Optimal time for the collection of high quality eggs was supposed to be from early to middle during the spawning periods. Considering that egg qualities were vulnerable within the period, hatchability, incidence of malformed larvae, SMOT and SAI were factors to be considered together to get good quality of eggs.

• Journal of Aquaculture
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• v.21 no.2
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• pp.96-101
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• 2008

To induce of maturation and ovulation, ovary with different development stage of oocytes of sevenband grouper Epinephelus septemfasciatus(n=51, TL $69.1{\pm}1.0$ cm, BW $5.8{\pm}0.3$ kg) rearing indoor-tank in mature and spawning season(June to July) were investigated by cannulation. Female with yolk globule stage oocyte($300{\sim}500{\mu}m$) was injected with human chorionic gonadotropin(HCG, 500 IU/kg BW). Oocytes developed at diameter $300{\sim}700{\mu}m$ in 24 hrs after the HCG injection, and the distribution ratio of over $800{\mu}m$ of oocytes diameter in the cannulated eggs were $91.3{\sim}98.8%(95.1{\pm}3.7%)$ in 48 hrs after the HCG injection. Ovulation was induced from 7 out of 8 female after the HCG injection. The total volume of stripped eggs was 2,480 mL, and the volume of buoyant eggs was 1,360 mL. The fertilization and hatching rates of buoyant eggs were $56.2{\sim}94.9%$ and $70.7{\sim}97.9%$, respectively. These results suggested that HCG 500 IU/kg BW effects on maturation and ovulation of female sevenband grouper with yolk globule stage of oocyte.

• Journal of Aquaculture
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• v.11 no.4
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• pp.565-572
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• 1998

Survival rate of larval red spotted grouper, Epinephelus akaara is very low, because mouth size of the larvae is too small to eat normal sizes of rotifers. In order to enhance larval survival, optimal culture conditions for larvae using different live foods and water temperatures were studied. Bigger live food produced larger size of rotifer, when the rotifer was cultured with three different live foods such as Tetraselmis tetrathele, marine Chlorella and Nannochloris oculata. Also, the size of rotifer produced was temperature-dependent showing that higher water temperature induced smaller rotifer. Survial rate of the larvae increased with the increase of water temperature up to $29{\circ}C$. Also, higher larval survials were found at the food density of 15 to 20 individuals per milliliter. The larvae fed L-type or small individuals of L-type rotifer died all within a week, although the larvae fed S-type or small individuals of S-type one survived successfully during this period. The size of small individuals of S-type rotifer collected through fine net became larger in a few hours within larval culture tank. Survival rate of grouper larvae with initial stocking density of 40 thousands in 6-ton concrete tank was 6.3% in 10 days and 0.2% in 53 days after hatching, respectively. Total length of the larvae reached around 29.5 mm in 53days after hatching.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.21-25
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• 2015

We studied the effects of temperature and salinity on the egg development and larvae of sevenband grouper Epinephelus septemfasciatus under sea cage culturing condition. In regard to rearing environment, the water temperature is $21.5{\sim}23.5^{\circ}C$ (mean $22.0{\pm}0.05^{\circ}C$) and the salinity is 32.0~33.0 psu (mean $32.5{\pm}0.05psu$). The time of egg development was positively proportional to water temperature with 29 hrs, 27 hrs, 24 hrs, 17 hrs, 15 hrs after fertilization in $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$ respectively. Each of the salinity hatching rate was 80% in the section of 15 psu, 81.8% in the section of 25 psu, 89.1% in the section of 30 psu, and 79.1% in the section of 35 psu. All things considered, the highest hatching rate appeared in the range of the section of 25~30 psu. Abnormalities of low salinity section, such as 15 psu (20.0%) and 20 psu (18.2%), was lower than the abnormalities of 35 psu that belongs to high salt section. The relation between the time of egg development (t:hour) and water temperature ($T:^{\circ}C$) was represented by the mathematical formulae. The mean biological minimum temperature was $5.4^{\circ}C$.

• Environmental and Resource Economics Review
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• v.14 no.3
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• pp.699-728
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• 2005

This article is basically an extension of Barten(1993), Brown et al. (1995), Holt and Bishop's(2002) price formation system. A new dynamic price formation system is attempted considering full rationality of the consumers' side. The underlying idea of the new dynamic price formation system is that consumers are rational and farsighted and thus consider past and future consumptions in addition to current consumption to accept the prices traders called. In an empirical application, the U.S. commercial fish demand data are particularly interesting to this analysis in which the species are over fished, including many of the most valuable species. Especially, the grouper-snapper complex are under management jurisdiction of the National Marine Fisheries Council. In the empirical section, it shows how to adapt the model to estimate the marginal values to consumers of commercial fisheries. Since it is conceived of regulations as inducing movements along the marginal value curves, it is of growing importance to regional and national policy makers who are confronted with competing claims on diminishing fish stocks by commercial fisheries interests. It performs well and shows the plausible signs and magnitudes of price flexibilities and interaction among species. It further contributes to the general methodology of applied economics.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.2
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• pp.526-536
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• 2015

Changes of oxygen consumption in juvenile giant grouper, Epinephelus lanceolatus were investigated in order to find out the physiological responses associated with freshwater and low salinities acclimation. Salinity changes in this experiment were set as follows; 35 psu (Exp. I) as control, decrease in the manners of $35{\rightarrow}20{\rightarrow}10{\rightarrow}0$ psu (Exp. II), $35{\rightarrow}10{\rightarrow}0$ psu (Exp. III) and $35{\rightarrow}0$ psu (Exp. IV). The average oxygen consumption at $27^{\circ}C$ in Exp. I (control) was $106.9{\pm}0.7mg$ $O_2/kg/h$. In Exp. II, according to the changes of $35{\rightarrow}20{\rightarrow}10{\rightarrow}0$ psu in freshwater acclimation, fish showed the gradual decrease in oxygen consumption as $108.1{\pm}2.1$, $99.6{\pm}2.9$, $74.6{\pm}0.9$ and $62.7{\pm}1.0mg$ $O_2/kg/h$, respectively. The fish in Exp. III also revealed the same tendency as $106.5{\pm}1.3$, $77.0{\pm}1.2$ and $64.7{\pm}1.2mg$ $O_2/kg/h$, respectively. In Exp. IV, fish showed the decreased oxygen consumption from $109.0{\pm}0.9mg$ $O_2/kg/h$ of 35 psu to $71.6{\pm}2.0mg$ $O_2/kg/h$ of 0 psu. Giant grouper is thought to be a diurnal fish species, because the level of oxygen consumption during light period was higher than that during dark period.