• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.500-504
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• 2013

A total of 24 juvenile specimens of Thunnus tonggol (5.45~7.26mm in total length) of the Sombridae were collected from the southeast sea of Jeju Island during 26~30 July, 2013. Twenty-four specimens identified T. tonggol have melanophores distributed on the 1st dorsal-fin rays, the dorsal of head and vetral side. Three individulas were identified using mitochondrial DNA cytochrome oxidase submit 1 (CO1) sequences (452 base pairs). All were identified as T. tonggol, their mtCO1 sequences being consistent with those of Thunnus tonggol (d=0.000), followed by Thunnus albacares (d=0.002) and Thunnus obesus (d=0.007).

• Ocean and Polar Research
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• v.23 no.3
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• pp.285-290
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• 2001

The strength of juvenile black rockfish, Sebastes schlegeli, raised in different hatcheries for wild stock enhancement was evaluated in terms of resistance to an anesthetizing agent, tricaine methane-sulfonate (MS-222), and exposure to drying. The working dosage of MS-222 varied significantly with fish size and hatchery population. Smaller fish were less resistant to the chemical than larger ones. MS-222 effects also differed with fish growth history. The fish cultured in embanked populations showed stronger resistance, earlier recovery, and lower mortality, compared to those cultured in land-based tanks or collected from wild stocks. Similar results were seen in juveniles challenged to dry exposure. These results suggest that an embanked population of black rockfish is more resistant to anesthetic stress, expressed as anesthesia recovery and mortality, and that this population is healthier than others.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.4
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• pp.406-412
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• 2014

To evaluate the influence of burrowing substrate on the rearing performance and ambicoloration of cultured flounder, Paralichthys olivaceus, we compared the daily food intake (DFI), feed efficiency (FE), survival, growth, proportion of pigmented skin on the blind side, and proportion of ambicolored fish. We reared juvenile flounders [total length (TL) $4.46{\pm}0.06cm$, body weight (BW) $0.77{\pm}0.03g$] in dark-green fiberglass-reinforced plastic (FRP) aquariums without (control) or with gravel substrate at a density of 200 fishes/ton for 120 days. While there was no difference in survival rate or growth, the DFI was lower and FE higher in the group raised with substrate than in the control. The proportions of pigmented area on the blind side and ambicolored fish were significantly higher in the control tank. Therefore, the supplement of substrate on the aquarium bottom positively affects the feeding efficiency, and inhibits abnormal pigmentation on the blind side in flounder farming at high density.

• Journal of Aquaculture
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• v.9 no.3
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• pp.233-237
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• 1996

A growth study was conducted to investigate the effect of stocking density on performance of juvenile fat cod (Hexagrammos otakii Jordan et Starks.). Fish averaging 13 g were stocked into duplicate tanks ($250\;{\ell}$ each) at four different densities of 330 g/$100\;{\ell},\;660\;g/100\;{\ell},\;990\;g/\;100\;{\ell}$, and $1330\;g/100\;{\ell}$, and fed MP diet containing $50\%$ frozen horse mackerel and $50\%$ commercial binder meal for 2 months. Weight gain, feed efficiency, survival rate, and protein retention were decreased as density increased. Whereas these parameters were not significantly different (P>0.01) fish stocked at initial stocking densities of $330\;g/100\;{\ell},\;660\;/g/100\;{\ell}\;and\;990\;g/100\;{\ell}$. Moisture and lipid content of whole body were not affected by stocking densities (P>0.01). These results indicate that stocking density should be considered, and $1{\~}2$ kg fish/$100\;{\ell}$ final stocking density for juvenile fat cod could be used to decrease production cost for the indoor tank (culture) system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.263-269
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• 2003

Morphological development of eggs, larvae and juvenile of the sunrise sculpin, Pseudoblennius cottoides were studed in the field and laboratory at the coastal Dolsan-do, Yeosu-shi from October, 2000 to April, 2001 Egg mass of Pseudoblennius cottoides in peribranchial cavity of Halocynthia hilgendorfi, were observed during late fall to winter in the study area. Fertiliged eggs were spherical in shape, demersal, adhesive, transparent and greenwish yellow color, measuring 1.84 mm (1.83-1.87 mm) in diameter. There were numerous and 17 (15-20) various-sized oil globules accounted in the yolk. Granular materials formed a mass in the yolk. Fertiliged eggs hatched at 301 hr 20 min after morula stage. Newly hatched larvae 6.31 mm (6.24-6.37 mm) in total length (TL), had a large yolk. At 3 days after hatching, the larvae, 6.77 mm (6.69-7.14 mm) in TL came out through the excurrent siphon of Halocynthia hilgendorfi. At 13 days after hatching, the larvae 12.59 mm (12.42-12.63 mm) in TL transformed to postlarval stage. At 32 days after hatching, postlarvae of TL 19.18 mm (19.01-19.46 mm) have reached the juvenile stage.

• Development and Reproduction
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• v.2 no.1
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• pp.81-87
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• 1998

A scanning electron microscopic study on the glochidial encystment and excystment during the development of Anodonta arcaeformis flavotincta on Carassius auratus, a common natural host fish, was carried out. The glochidia were attached to the fins, buccal cavity and gills of the host fish within 30 minutes. In this study, the fins of host fish infected with the glochidia were examined in a time series. The attachment rates of the glochidia on the pectoral fins, caudal fin and pelvic fins of the host fish were 30%, 22%, and 17%, respectively. The glochidia which attached to the fish became encysted within 27 hrs. The process of encystment progressed slowly. Ti took 24 to 27 hours in the formation of the primary cyst, and after 5 to 6 days, the larvae was covered completely with the epithelial cels of the host tissues. The process of detachment of juvenile clam was observed on the 8th day after host infection. Most of the juvenile clams have sloughed from the cyst of the host within 15 days. No significant size difference was observed in the glochidia and the juvenile which were found before attachment and after detachment from the cyst of the host fish.

• Journal of Families and Better Life
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• v.25 no.4
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• pp.31-41
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• 2007

This study aimed to develop a cognitive-behavioral group counseling program for depression and aggressiveness in adolescents with delinquent propensity and to examine its efficacy through pre- and post-tests. The program included cognitive restructuring, exposure training, social skills training and relaxation training. Juvenile Delinquency Scale, BDI, K-YSR, and BDHI were administered to 520 3rd grade middle-school female students to assess their levels of delinquency, depression and aggressiveness. Initially 41 students who met all the following criteria were selected: 1) top 15% scores on Juvenile Delinquency Scale, 2) top 30% scores on BDI, K-YSR and BDHI respectively. Individuals currently receiving clinical treatment were excluded. Finally 39 students were selected and randomly assigned to either a treatment group(n=20) or a control group(n=19). Then the students in the treatment group were divided into 4 subgroups. The program consisted of 12 weekly sessions, approximately $1.5{\sim}2$ hours in duration. Pre- and post-tests administered to both groups included Juvenile Delinquency Scale, BDI, K-YSR, BDHI, and CLAB. Additionally, MESSY for teachers was added at pre- and post-tests. The collected data were statistically analyzed through independent t-test and paired t-test. The results of the study were as follows: 1) The students in the treatment group showed a significant reduction in the level of depression and aggressiveness in comparison with those in the control group. 2) Teachers reported a significant reduction in internalizing/externalizing behaviors of the students in the treatment group.

• Journal of Aquaculture
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• v.9 no.1
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• pp.11-18
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• 1996

We described morphological characteristics of embryonic, larval, and juvenile period of the yellow puffer, Takifugu obscurus. We defined seven periods of embryogenesis the zygote, cleavage, blastula, gastrula, segmentation, pharygula, and hatching periods. The eggs were adhesive and spherical in shape. The egg yolk had numerous tiny oil globules. Hatching began about 280 hours after insemination at $17.0{\pm}1.0^{\circ}C$ water temperature. Melanopores of star shape were seen on yolk, head and trunk during the pharygula and hatching period. The hatched larvae haying large yolk were $3.00\~3.54$ mm in size with $25\~26$ myomeres. The larvae completely absorbed the yolk materials and oil globules within 7 days after hatching and became post-larvae. Laval fish became juveniles within 60 days after hatching, and they reached $23.54\~30.12$ mm in total length and had fin-rays.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.136-143
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• 2003

The eggs of Favonigobius gymnauchen attached on the under side of a small stone were collected off Seongsan-eup Cheju-do in August, 2000 to investigate their development of egg, larvae and juveniles. The fertilized eggs were elliptical in shape (mean long axis: 1.50 mm; mean short axis: 0.57 mm) and transparent. There were filaments on one side of the egg membrane. Larvae hatched at 48 hrs 50 mins after morula stage with 25-26 myotomes in $22.8-28.5^{\circ}C\;(mean\;24.7^{\circ}C).$ The newly hatched larvae were 2.31-2.49 mm (mean 2.37 mm n=10) in total length (TL) and their mouth and anus were already opened. Their melanophores were appeared on the over gas globule, around anus and the part of caudal peduncle with 24-25 myotomes. At 4-5 days after hatching. larvae attained 3.81-4.07 mm (mean 3.96 mm, n=10) in TL and their yolk sac was completely absorbed. They began to eat rotifer and transformed to postlarvae stage. At 14 days after hatching, postlarvae attained 6.17-6.31 mm (mean 6.21 mm, n=10) in TL and their caudal notocord was flexed $45^{\circ}$ upward. At 24 days after hatching, postlarvae attained 8.69-9.10 mm (mean 8.87 mm, n=10) in TL had reached the juvenile stage. All fins were formed with the complete set of fin rays with the following counts: dorsal fin rays IV-I, 9-10; anal fin rays I, 9; pectoral fin rays 17; ventral fin rays: I, 5; caudal fin rays: 9+8= 17.

• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.146-153
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• 2000

The development of larvae and juvenile of the smoothskin sculpin (Ocynectes modestus) caught at Pusan brook in May and June 1995 was described. Yolk was completely absorbed when the larvae was about 6.28 mm in average standard length (ASL) with 32~33 myomeres. Flexion of the notochord started when the juvenile was about 7.36 mm in ASL and finished about 9.34 mm in ASL, respectively. Aggregate numbers of all fin rays were completed at over 10.08 mm in ASL, when the larvae reached the juvenile stage. One pairs of flaps were observed on the dorsal surface of the head at 10.08 mm in ASL. The juveniles longer then 14.00 mm in ASL has the same pigment pattern as that of adults. A new Korean name "Min-Ga-Si-Ggeog-Jeong-i" is proposed for this species.