• Development and Reproduction
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• v.25 no.3
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• pp.157-171
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• 2021

To determine whether the reproductive processes of sea bass, Lateolabrax japonicus, proceed normally after transportation from an outdoor net-cage into indoor tanks, we examined changes in the gonadosomatic index (GSI), histological gonadal tissue, and plasma levels of sex hormones (testosterone and estradiol-17ß) during their annual reproductive cycle. We also measured maturation and spawning across two sea water salinity levels (full and low salinity). Fecundity was estimated by the relationship between egg number and body size in female sea bass. Monthly changes in the GSI, histological gonadal tissues, and oocyte size showed both male and female sea bass reach final maturation in January and February, respectively, indicating that the spermiation of males occurs earlier than the spawning of females. The histological results indicated that the sea bass is a multiple spawner, similar to many marine teleosts, exhibiting group-synchronous oocyte development. Female maturation and spawning were enhanced in lower salinity seawater (29.6-31.0 psu) compared to that of normal salinity (34.5-35.1 psu). These results confirm that sea bass reproduction can occur successfully in captivity and imply that fertilized eggs can be collected from February to March. Additionally, our results show that lower salinity enhances oocyte maturation and spawning of female sea bass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.272-281
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• 1994

To investigate the effects on pigmentation and carotenoids metabolism of sea bass, Lateolablax japonicus, by supplemented carotenoids, fish were fed the diets each containing ${\beta}$-carotene, lutein ester, astaxanthin, astaxanthin monoester and astaxanthin diester for 8 weeks. Carotenoids in the integuments were analyzed. The important carotenoids in the integuments of sea bass were tunaxanthin and lutein. ${\beta}$-carotene, ${\beta}$-cryptoxanthin, zeaxanthin and ${\beta}$-carotene triol were minor contributors. Differences in the content of ${\beta}$-carotene, tunaxanthin fraction and lutein were observed between the natural and cultured sea bass. The wild sea bass contained higher amounts of tunaxanthin fraction and lutein, but contained lower amounts of ${\beta}$-carotene than cultured sea bass. In cultured sea bass with supplemented carotenoids, carotenoid deposition was higher in order of astaxanthin monoester group, astaxanthin group and astaxanthin diester group. Based on the contents and composition of carotenoids in each group after the feeding the experimental diet, The metabolism of carotenoid in sea bass was presumed to be the reductive metabolic pathways: astaxanthin to tunaxanthin via ${\beta}$-carotene triol, zeaxanthin and lutein.

• Journal of Aquaculture
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• v.11 no.3
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• pp.345-352
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• 1998

The effect of starvation on the growth and hepatocyte nuclear size of larval rockfish Sebastes schlegeli and spotted sea bass Lateolabrax sp. were studied. The growth of total length and wet weight in both rockfish and spotted sea bass starved were lower than their control counter-parts. The nuclei sizes of parenchymal cells in the liver of rockfish and spotted sea bass were correlated with the nutritional status of their first-feeding larvae. The result suggested that hepatocyte nuclear size in rockfish and spotted sea bass could be used as an alternative indicator for the identification of starving condition and such karyometry might be criteria for evaluating the successful transition from endogenous to exogenous feeding regime.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.920-928
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• 2015

This study aims to reveal the relationship between growth of young sea bass and environmental variables in two adjacent eelgrass beds. Fishes were collected from Gamak Bay (GB) and Yeoja Bay (YB) on the southern coast of Korea from February 2006 to February 2007 using a dragnet (15 m in length and 3 m in width). During the study period, a total of 367 individuals of young sea bass Lateolabrax japonicus were collected from GB (171 inds.) and YB (196 inds.). Significant differences were observed in the occurrence periods and growth patterns of young sea bass, as well as in environmental variables between GB and YB. Young sea bass were collected from April to December in GB, but from April to July in YB. These differences may be associated with differences in eelgrass density, leaf width, and zooplankton density between GB and YB.

• Journal of Aquaculture
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• v.16 no.1
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• pp.31-36
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• 2003

Two experiments were conducted for the physiological and growth responses of yearling sea bass, Lateolabrax japonicus (total length 24.4$\pm$1.5 cm, body weight 125.4$\pm$25.4 g) by the manipulation of salinity. To study the physiological responses of the sea bass by acute salinity change, we changed water salinity from 30 ppt into 2 ppt in rearing tank through 1 hour or 6 hour. To access the effect of salinity in the growth of sea bass, we also examined the growth of the sea bass in 2, 10, 20 and 30 ppt for 180 days. After salinity change, all yearlings appeared some stress response and ions changes in blood. The yearlings showed a slow recovery by an acute salinity exchange, but a fast recovery by slow salinity exchange. In the study about the influence of salinity in growth, although the food intake of yearlings in 20 ppt was significantly higher than the yearling in the other salinities, feed efficiency was higher in 10 ppt than the other salinities. However, the food intake and the feed efficiency in 2 ppt were significantly lower than in other groups. The growth of yearlings was significantly faster in 20 ppt than in the other salinities, but the growth showed significantly slower in 2 ppt than in the other salinities.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.651-659
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• 2023

The effect of bio-logger tagging location on blood characteristics and bio-logger attachment efficiency in spotted sea bass (mean body weight 2356.7 g) was investigated. The fish were tagged at four different tagging locations: no-tag (control), operculum attachment (OA), dorsal muscle attachment (DA), and cauda peduncle muscle attachment (CA). The blood properties and bio-logger attachment efficiencies were examined on days 1, 7, 14, and 35 after tagging the bio-logger at each tagging location. During the experimental periods, the concentrations of hematocrit and hemoglobin in whole blood, and GOT (glutamic oxaloacetic transaminase), GPT (glutamic pyruvic transaminase), total protein (TP), glucose, total cholesterol, cortisol, and superoxide dismutase in plasma were not affected by the attachment location of the bio-logger, however, the TP concentration was significantly lower in OA than in the control group on day 7. After tagging for 35 days, the efficiencies of bio-logger attachment in the OA, DA, and CA after tagging for 35 days were 33.3%, 100.0%, and 33.3%, respectively. These results indicate that, in our experimental condition, the most appropriate bio-logger attachment location is DA, providing basic information on bio-logger utilization methods for ecological and biological biotelemetry surveys of the spotted sea bass.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.17 no.1
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• pp.1-6
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• 1981

The selective response of the sea bass, Lateolabrax japonieus and the gray rock cod, Sebastes inermis to the colored twines was studied in a white tiled aquarium C400LX60WX70H em), by use of Y -maze made of gray plastic plate. Anyone of the different colored twines, white, black, blue, yellow and red, was strung crosswise on a rectangular frame which was mounted to one of the two outlet ends of Y -maze, and another colored twine was used to the other end of the Y -maze. In each trial, a fish was guided toward the inlet of the Y -maze to let the fish select either one of the two different colored twines. The results obtained are aS follows: 1. Sea bass preferably selected the colored twines in a order of white, blue, yellow, black and red with significant difference. 2. Gray rock cod showed little difference in selecting colored twines even though the fish selected white one a little more frequently.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.777-782
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• 2000

To investigate the effects of growth and body composition of spotted sea bass (Lateolabrix sp.) by the supplemented dimethyl-$\beta$-propiothetin(DMPT). fish was fed the diets each containing 3 mM, 5 mM, 7 mM and 10 mM for eight weeks. The weight gain, feed efficiency and feed intake were significantly increased with dietary DMPT level. Condition factor was reduced by dietary DMPT supplementation. Crude protein content of fish after eight weeks increased with dietary DMPT level, whereas crude lipid content deceased with dietary DMPT level. Amino acid content was higher in DMPT-added group than control group. Amino acid composition was not influenced by dietary DMPT supplementation. Fatty acid content deceased with dietary DMPT level.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.3
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• pp.158-168
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• 2006

A study on the species composition and seasonal variations of fishery creatures caught by a funnel net was carried out in the coastal water off Dolsan Island, Yeosu from 2002 to 2003. During the study period, a total of 23 fishery creatures species were caught. Seabream(Acanthopagrus schlegeli), sea bass(Lateolabrax japonicus), mullet(Mugil cephalus), puffer(Takifugu niphobles) and rockfish(Sebastes inermis) predominated. These five species accounted for 85.1% of the total number of fishery creatures caught. Seasonal peaks of number of species occurred in summer, while those of number of individuals occurred in autumn. The lowest number of species and individuals were observed in winter. The large annual variation of diversity indices were observed from May to August. These large annual variation of diversity indices were mainly due to predominance of seabream, sea bass and mullet which accounted for most of all fishery creatures caught. The seasonal variations of fishery creatures showed that sea bass and mullet were caught mainly from spring to summer, seabream and puffer were caught mainly in autumn, and rockfish and brotula(Hoplobrotula armata) were caught mainly in winter.

• Journal of fish pathology
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• v.22 no.2
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• pp.163-166
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• 2009

The ectoparasite ciliate Trichodina has been recorded from above 100 species of freshwater and marine fishes. In April 2009, we investigated the trichodia infection in 13 species of marine fishes captured by emplacement net and gill net in order to understand trichodina infection status among the natural fish populations along the Namhae-Gun coast area, the southen coast of Korea. Trichodina infection was observed in 10 out of 10 sea basses Lateolabrax japonicus, 2 out of 5 finespotted flounder Pleuronichthys cornutus and 1 out of a stone flounder Kareius bicoloratus. The sea bass infected with the parasite showed hypertrophy and exfoliation in gill epithelium. In addition, hyperplasia and lamellar fusion of gill filament were noticed among naturally affected sea bass.