• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.194-204
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• 2018

In order to minimize the damage on the red sea bream Pagrus major by a harmful dinoflagellate Cochlodinium polykrikoides, we investigated the effect of feeding, starvation and stocking density on the survival rate, growth, growth restoration and physiological response of P. major exposure to C. polykrikoides. The experimental groups were divided into three groups such as F-HD (feeding and high density with $6.4kg/m^3$), S-HD (starvation and high density with $6.4kg/m^3$) and S-LD (starvation and low density with $3.2kg/m^3$) according to stocking density and starvation in marine cage ($11m{\times}11m{\times}5m$). The F-HD was fed throughout the experiment for 9 weeks, whereas S-HD and S-LD were not fed for 5 weeks and then refeeding for 4 weeks. Survival rate was the lowest in F-HD (85.5%) and S-LD was the highest (97.3%). The growth rates of S-HD and S-LD were significantly lower than F-HD during starvation period for 4 weeks, but rapidly recovered after feeding. The nutritional status such as ALB, TP, TCH, TG were similar to tendency of growth data. Ht, Hb, AST, ALT and GLU levels were significantly higher in the F-HD than in the starvation groups at the same time (in 3 week) during starvation period. But starvation groups did not differ during starvation period. As a result, F-HD is more sensitive to stress than S-HD and S-LD. Thus, during C. polykrikoides bloom period, starvation and stocking density control can help survival and growth restoration of the red sea bream.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.36-36
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• 2003

In the present study, growth performances of the offspring from selected brood line were compared to those of the offspring from non-selected brood line of red sea bream. Offspring groups were mass produced separately from two brood lines, selected and non-selected Korean strain. Selected brood line have been selected by fish size for four generations (upper 5∼30% per generation) and non-selected brood line is the second generation of wild population at south sea in Korea. There's no significant difference in body length between offspring from selected and non-selected brood line during early growing stage (until 96-days old). However, offspring from selected brood line had superior body weight growth than offspring from non-selected brood line. At sea cages rearing trials with communal stocking, Offspring from selected brood line showed significantly better performance in body weight, body length, weight gain, specific growth rate and feed consumption (but not in feed conversion ratio) than offspring from non-selected brood line. At 24 months old, offspring from selected brood line grew faster 1.10 times in body length and 1.41 times in body weight than offspring from non selected brood line. The response to selection when compared to a non-selected line is on average of 10% in weight per generation at 24 months old.

• Journal of Aquaculture
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• v.11 no.4
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• pp.529-546
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• 1998

Gonadal part that developed by indifferentiation period for 6 months after hatching is made as gonad and fat body. These gonad are thin semi-transparant and undistinguished germ cell. Germinal epithelium is distinguished by development of gonad epithelial tissue from 7 months after hatching. Sex differentiation is begun by oogonia develoment at 8 months after hatching. Primary oocytes grow over germinal epithelium of gonadal cavity, at 9 months after hatching, gonadal cavity become ovarian cavity as they increasing. As soon as oocytes at 13 months after hatching are filled with the whole part of gonad, degeneration of oocyte is begun. And then, gonad has cavity tissue, a small number of oocyte are located in gonadal cavity. At 15 months after hatching, new primary oocyte develop and cavity of ovarian tissue in the central of ovarian cavity. Spermatogonia multiplicate and cavity tissue consist of testicular tissue. These gonad become hermaphrodite and then ditermine the sex of female and male. These results show the red sea bream is juvenile hermaphrodite and undif-ferentiated gonochoristic teleost. Male and female differentiation type of gonad is divided in undifferentiation stage, oogonia-like stage, ovary-like stage, ovary development stage, hermaphroditic testis stage, hermaphroditic ovary stage, and testis development stage. Undifferentiation stage is continued total lenth 18cm at 13 months after hatching. ovary-like stage is continued total length 11~18cm at 13 months after hatching. Ovary-like stage is continued total length 14~26cm at 10~14 months after hatching. Ovary development stage begins from total length 20cm, 14 months after hatching. At 20 months after hatching, 44 percent of total sampled individuals had ovary. Hermaphroditic ovary stage first begins total length 19~20 cm at 15 months after hatching, but it is not observed total length 28~29cm at 20months after hatching. Hermaphroditic testis stage first begins total length 21~22cm at 20months after hatching and is continued for 20months. Testis development stage first begins total length 20~21cm at 20 months after hatching, and is occupied 33 percent total length 28~29cm at 20 months. The beginning of sex differentiation more than 50 percent is from total length 16cm at 11 months after hatching. Sex determination begins total length 20cm, 14months after hatching in female and total length 20cm, 15 months after hatching in male. Sex determination more than 50 percent begins total length 23cm,, 17 months after hatching. Undifferentiated gonadal part of red sea bream consist gonad and fat body. As differentiation is going on and gonad is growing, fat body shrinks. This appearence is showed the same tendency in 3-year old red sea bream. 1.9mm larvae after hatching grow about 19mm larvae for 47 days. The relationship between the total length and body weight of larvae and juveniles in $BW=4.45{\times}10^{-6}TL^{3.4718}$ r=0.9820. Fishes in cage culture grow to maximum total length 28.4cm. The relationship between the total length and body weight of these fishes is $BW=2.36{\times}10^{-2}TL^{2.9180}$, r=0.9971. Undifferentiated gonadal part of red sea bream consist gonad and fat body. As differentiation is going on and gonad is growing, fat body shrinks.

• Ocean and Polar Research
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• v.26 no.3
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• pp.415-423
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• 2004

An experiment was conducted to investigate the differences of total ammonia nitrogen (TAN) excretion rates and feces production rates among the offsprings from cultured Japanese strain (JJ, mean BW; $17.1{\pm}0.1g$), intraspecific hybrid strain between cultured Japanese and selected Korean strain (JK, mean BW: $17.1{\pm}0.1g$) and selected Korean strain(KK, mean BW: $21.5{\pm}0.1g$) of red sea bream in order to compare their dietary protein utilization efficiency. Fish were hand-fed with a commercial diet containing 46.7% crude protein for 2 weeks, three times daily 09:00, 13:00 and 17:00. After daily feeding, the TAN excretion rates reached peaks of 49.03, 58.75 and 36.26mg/kg fish/hr for the JJ, JK and KK strain, respectively, during the daytime. The value of the KK strain was significantly lower than that of the JJ and JX shuin (P<0.05), however daily TAN excretion rates of the JJ, JK and KK strain were not different (P>0.05). When fish were fed at satiation after 4 days of starvation, TAN excretion rates reached the maximum values 4 hours after the feeding fur the KK (31.23 mg/kg fish/hr) and 6 hours after the feeding fur the JJ (44.19 mg/tg fish/hr) and JK strain (41.70 mg/kg fish/hr). After 3 days of starvation, the daily endogenous TAU excretion rates (ETE) for the JJ, JK. and KK strain were 286.91, 215.66 and 179.29mg/kg fish/day, respectively. The value of the KK strain was lower than that of the JJ and JK strain (P<0.05). The total feces production rates of the JJ, JK and KK strain were not significantly different, however the proportions of feces production rates by time for the JJ, JK and KK strain were different (P<0.05). As overall results, efficiency of dietary protein utilization of JJ, JK and KK seems to be different and KK strain could offer a desirable option for aquaculture purpose.

• Korean Journal of Ichthyology
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• v.2 no.2
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• pp.138-148
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• 1990

The influence of starvation on morphological change of the red sea bream larvae was examined at Song-ji fish hatchery, Tongyong-Gun, Kyongnam Provice in July 1988. The results obtained are as follows: 1) The larvae of red sea bream began to feed on rotifers in 2 days after hatching. In case of non-feeding, all of the larvae died in 5 days after hatching and the larvae which feeding delayed 1 and 2 days from normal first feeding schedule also died 100 in 6 days after hatching. 2) With the exhaustion of the yolk, the total length, body length, myotome height and gut height of unfed larvae decreased. 3) The ratio of height to myotome height in unfed larvae has declined most rapidly compare to other demensions while starving. At 5 days after hatching, the ratios of these of starving larvae and fed larvae were 0.306 and 0.010, respectively. 4) The morphology of starving larvae at 6 days after hatching are characterized as sharpened jaw, projected edge of lower part of clavicle and slender gut.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.777-790
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• 2022

This study was conducted to investigate the nutritional characteristics of the following Korean-distributed fish species commonly consumed as sliced raw fish (CC-SRF): olive flounder Paralichthys olivaceus (OF), red sea bream Pagrus major (RS), Atlantic salmon (AS), coho salmon (CS) and sockeye salmon (SS). The crude protein and lipid contents of OF, RS, AS, CS and SS were 20.2% and 5.5%, 21.2% and 6.8%, 17.7% and 18.5%, 18.3% and 16.1%, and 20.4% and 5.7%, respectively. Regardless of the type and weight of fish species, the major amino acids were leucine, lysine, aspartic acid, and glutamic acid, whereas histidine was identified as a limiting amino acid. The major minerals in all CC-SRF were P, K and Se based on the recommended daily intake or sufficient intake for Korean males aged between 19-49 years. Among the different types of all CC-SRF, the intake of OF and SS lipids is predicted to be associated with a lower n-6/n-3 fatty acid ratio, whereas among the free amino acids, which are expected to have health functionality, we identified taurine in OF and RS, and anserine in salmons. The digestibility of OF, RS, AS, CS and SS were 60.7%, 54.9%, 48.5%, 49.6%, and 53.4%, respectively.

• Fisheries and Aquatic Sciences
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• v.6 no.3
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• pp.160-163
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• 2003

Mortality of several species of fish and shellfish exposed to Harmful Algal Blooms (HABs) caused by Cochlodinium polykrikoides, Heterosigam akashiwo, Alexandrium tamarense, Eutreptiella gymnastica, Heterocapsa triquetra and Prorocentrum micans was studied. When fish were exposed to a cell density of 8,000 cells $mL^{-1}$ in C. polykrikoides, $35\%$ of flatfish and darkbanded rockfish died within 48 hrs. However, jacopever rockfish had mortality of higher than $85\%$. Rock bream, filefish and red sea bream showed $100\%$ mortality within 10 hrs with an exposure cell density of 8,000 cells $mL^{-1}$. The rest of HABs except for C. polykrikoides showed that there was no fish and shellfish death throughout the 48 hrs even in the maximum cell density of 100,000 cells $mL^{-1}$ These results imply that C. polykrikoides can have a serious impact on fish mortality and it is regarded as an ichthyotoxic dinoflagellate. The fish death may be attributed to anoxia caused by a combination of the production of reactive oxygen species (ROS) and polysaccharide from C. polykrikoides during blooms.

• Journal of fish pathology
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• v.24 no.2
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• pp.121-129
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• 2011

Aquatic animal raised in hatcheries play an important role in supplying seedling to stock enhancement and seed quality, especially, seed health is the key factor for survival in the field after release and for stocking effectiveness. We have inspected the hatchery-reared seeds of 33 marine species and 12 freshwater species for legally designated diseases in stock enhancement program in 2010. Results showed that abalone was the most abundant as 20.0% in the marine species group and then sea cucumber (15.6%), olive flounder (8.4%), rockfish (6.7%), black sea bream (6.3%) and swimming crab (6.1%) were followed. Crucian carp was the most abundant as 19.4%, and then eel (11.8%), Korean bullhead (10.9%), mandarin fish (10.8%), melanian snail (8.4%), catfish (7.7%) were followed in the freshwater species group. The total number of inspection cases for eight pathogens in this study were 2,105 and disqualification cases were 30 by detection of aquatic animals pathogens such as koi herpesvirus (KHV), red sea bream iridovirus (RSIV), white spot syndrome virus (WSSV) or viral haemorrhagic septicemia virus (VHSV).

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.752-752
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• 2003

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.2
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• pp.161-170
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• 1982

A trial on the seed production of red sea-bream (Chrysophrys major) was made in Jejudo island at the southern end of Korea, from June, 1980 to August, 1981. Histological observation of the gonads indicated that the main spawning season was June to early July in Jejudo area. The newly-hatched fry were fed Brachionus sp. in the later stages Artemia nauplii, Tigriopus sp. and the minced fish flesh were given. Though during the winter season the water temperature in rearing tanks was decreased as low as $9.2^{\circ}C$, continuous feeding to the juveniles was carried out, showing body weight increase. This implies that winter rearing of juveniles in the near-shore facilities is feasible in the vicinity of Seogwipo area, in Jejudo. Feed coefficient of the juveniles (>23.2 g) was $4.16\sim4.77$ when fed the minced fish flesh.