• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.63-68
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• 2001

The skeletal development of the larvae and juvenile of red marbled rockfish, Sebasticus tertius (Barsukov et Chen) was studied based on individuals that were discharged and reared in the laboratory from April to May 1997. In 8 days after bearing, the postlarvae attained 4.42 mm in total length (TL), and its parasphenoid, premaxillary, maxillary, and clavicle were ossified for the first time at this stage. In 15 days after bearing, the postlarvae attained 5.23 mm in TL, and its pterotic, basioccipital, exoccipital, opercle, and preopercle were ossified, with one spine on the each cranium and preopercle. In 27 days after bearing, the postlarvae attained 8.81 mm in TL, its vertebra were posteriorly ossified to the 15th centrum, and five spines were formed on the preopercle. In 39 days after bearing, the juveniles attained 14.21 mm in TL, and the all bones were almost completed at this stage.

• Journal of Sericultural and Entomological Science
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• v.32 no.1
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• pp.31-37
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• 1990

For fine-denier cocoon filament production, the precocious trimolting silkworms were induced by the treatments with both the imidazole compound "KK-42" hating anti-juvenile hormone activity and high temperature, and their growth, dietary efficiency, cocoon and cocoon filament qualities were compared with those of normal tetramolters as control. 1. The percentage of precocious trimolters was higher in the application of KK-42 than the treatment of high temperature. The effective concentration of KK-42 was 10$\mu\textrm{g}$/1arva. The high temperature treatment for 48 hour was more effective than 36 hour treatment, and silkworm larvae fed on mulberry leaves were more sensitive than artificial diet to induce trimolters. 2. The larval duration of the trimolters induced by KK-42 was 5.17 day shorter than that of normal tetramolters in mulberry leaves rearing, and the increasing pattern of body weight in the 4th inster larvae of trimotlers was similar to the 5th instar larvae of normal tetramolters. 3. The qualities such as cocoon weight, cocoon layer weight and cocoon layer ratio of precocious trimolter induced by KK-42 were much lower those of normal tetramolters: the cocoon weight and cocoon layer ratio were 0.78g, 14.2cg and 18.4% in mulberry leaves rearing, and 0.86 cg, 10.3cg and 12.3% in artificial diet rearing, respectively. 4. The size of cocoon and cocoon filament was smaller in the precocious trimolter, both KK-42 and high temperature, as compared with that of the normal tetramolters. 5. The efficiency of cocoon layer production of the precocious trimolters by the KK-42 was lower than that of the normal tetramolters: amount of the cocoon layer production per 1g of dry mulberry leaves ingested was 7.97cg in the precocious trimotors, while 9.20cg in the normal tetramolters.

• Korean Journal of Ichthyology
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• v.36 no.1
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• pp.94-100
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• 2024

During ichthyoplankton survey in the southwestern sea of Korea, we collected six individuals of noodlefish larvae and juveniles between April and May 2023. They were identified as Neosalanx anderssoni by mitochondrial DNA cytochrome c oxidase subunit I or 16S ribosomal RNA sequences, and their external morphological traits were described for the first time. All six individuals have a slender and elongated body. When preflexion and flexion larval stages (10.24 mm notochord length, NL and 15.47 mm total length, TL, respectively), oval-shaped black melanophores were distributed in a row along the ventral side of the gut. However, when postflexion larval and juvenile stages (23.58~25.90 mm TL, and 29.20~31.26 mm TL, respectively), melanophores on the ventral side of the gut were disappeared, and dark spot-shaped melanophores appeared along the dorsal side of the gut in a single row. Also, from the postflexion larval stage (23.58 mm TL), two large black spots began to appear symmetrically on the caudal fin. Our results suggest that N. anderssoni may use coastal area as spawning and/or nursery ground unlike previous study (Kim and Park, 2002).

• Development and Reproduction
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• v.10 no.1
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• pp.41-45
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• 2006

The spawning behavior of Liobagrus obesus was observed at Kumgang river, Yeongdong-gun, Chungcheongbuk-do from Apirl to July 2004. The fertilized eggs collected by dip net and skimming net were carried to the laboratory of Chonnam National University, and then egg, larvae and juvenils development were studied. Hatching of the embryo began about at 225 hrs 15 mins after morula stage in water temperature of $19.5{\sim}24.9^{\circ}C$(mean $22.8^{\circ}C$). The newly-hatched larvae were $7.30{\sim}7.90mm$(mean 7.66mm) in total length (TL), their mouth and anus were already opened with 14+28=42 myotomes. Sixteen days after hatching, the postlarvae were $13.00{\sim}14.05mm$(mean 13.48mm) TL, the yolk sac was completely absorbed. The juvenile stage was reached when all fin-rays were formed at 24 days after hatching, and $15.31{\sim}17.20mm$(mean 16.31mm) TL.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.1
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• pp.46-53
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• 2010

Spawning behavior and early life history of the tuman river sculpin, Cottus hangiongensis were studied in the laboratory and in the field at Wangpi Stream, Gyeongsangbuk-do, Korea, from January to December, 2007. The spawning ground was in the lower Wangpi Stream, which is a shallow region about 40cm or less in depth. During the spawning period, from March to April, mature males made nest cavities under stone 10 which they led a gravid female. The male and female then turned upside down, and spawning and fertilization occurred onto the ceiling of the nest cavity. After spawning, the male chased the female from the nest and mated with several other females. Fertilized eggs were spherical in shape, demersal, adhesive, transparent and yellow in color, measuring 1.86 mm (1.79~1.93 mm) in diameter. A mean of 17(12~22) various-sized oil globules were counted in the yolk. Granular materials formed a mass in the yolk. Fertilized eggs hatched at 256 hrs, 10 minutes after the morula stage under water temperature of $15.0{\sim}18.0^{\circ}C$. Newly hatched larvae 9.34 mm (9.02~9.69 mm. n=10) in total length (TL) had a large yolk At 14 days after hatching, larvae 11.40 mm (11.07~11.72 mm, n=10) in TL transformed to the postlarval stage. At 41 days after hatching, postlarvae of 18.42 mm (17.31~18.62 mm, n=10) in TL had reached the juvenile stage. The result of this study indicate that Cottus hangiongensis has the spawning ground in the lower stream and the amphidromous life history which is the different from that of Cottus poecilopus.

• Journal of Aquaculture
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• v.16 no.3
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• pp.129-134
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• 2003

Spawning induction and early growth of the sea urchin, Strongylocentrotus intermedius were studied with the purpose of artificial seedling production. Gonadosomatic index(GSI) of the sea urchin showed the highest value in October, and rapidly decreased in December. It means that October and November is the peak of spawning season of the sea urchin in the latitude. Spawning induction by injection of potassium chloride solution in October has showed 44.0~100.0% reaction rate, and were produced 6,300$\times$10$^4$ eggs. Spawned eggs have shown the fertilization rate of 92.3~98.2% and the hatching rate of 78.2~87.0%. The metamorphosis of larvae after hatching in the seawater temperature of 13.7~17.1$^{\circ}C$ resulted in early eight-armed larvae in 13 days and late eight-armed larvae in 20 days. The collection of progenies was possible in 24~25 days after hatching and collection rate was 18.5~26.1% (mean 22.3%). Test diameter immediately after collection had a mean 350 ${\mu}{\textrm}{m}$. Survival rate and test diameter of juvenile sea urchin after collection were 58.5%, 1.32 mm in 30 days, 27.7%, 3.82 mm in 92 days and 15.6%, 11.70 mm in 181 days, respectively.

• Korean Journal of Ichthyology
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• v.28 no.3
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• pp.179-185
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• 2016

To develop cultivation technique for Acipenser ruthenus and secure basic taxonomic materials, this study examined egg development and larva morphological development. This study used a couple of male and female broodstork matured in a PVC circle water tank (Ø 5 m) with the water temperature of $16.0{\pm}1.0^{\circ}C$ in June 2005. They were oval opaque and sinking cohesive eggs and the sizes of them were between $3.83{\sim}3.85(3.84{\pm}0.01)mm$ (n=10). As for the egg development, the dry process was adopted with artificial insemination in this study, and an hour after the insemination, the embryo disks were developed, 31 hours after the insemination, they reached the end of gastrula stage, and 82 hours (50%) after the insemination, they were hatched. Right after the hatch, the total lengths of larvae were $10.1{\sim}10.3(10.2{\pm}0.11)mm$ (n=10) with big yolks in the venter. 17 days after the hatch, the total lengths of them were $26.2{\sim}32.4(29.3{\pm}4.39)mm$ (n=10) and in the front of a dorsal fin there were 11 scute scales that started to make tracing development. As 50 days after the hatch, the total lengths were $86.4{\sim}93.1(89.8{\pm}4.71)mm$ (n=10), and fin rays all reached integer, they were moved to the larva apparatus.

• Korean Journal of Ichthyology
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• v.17 no.1
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• pp.29-35
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• 2005

Fertilized eggs of Takifugu pardalis (Temminck et Schlegel) were collected on the coast of Jook-do in Tongyong, Korea, from March 1997 to June 1999, and hatched and reared in the laboratory to investigate osteological development of the larve and juveniles. The newly hatched larvae attained a mean of $3.13{\pm}0.05mm$ in total length (TL). Ossification first began in the parasphenoid, premaxillary and dentary. At 5 days after hatching, the postlarvae attained a mean of $3.82{\pm}0.03mm$ in TL, and their sphenotic, prefrontal, preopercle, opercle, maxillary, and articular were ossified. At 15 days, the postlarvae attained a mean of $7.84{\pm}0.06mm$ in TL, their nasal and posttemporal bones were ossified and the hyoid arch completed ossification. Ossification of all bones was completed in the juveniles (mean = $10.21{\pm}0.06mm$ in TL) at 21 days.

• Korean Journal of Ichthyology
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• v.2 no.2
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• pp.159-168
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• 1990

Parental fish of R. uyekii(Mori) were colleted from the Nakdong River, Korea. Artificial insemination was carried out 4 times during June using the same pair (a female 52.70 mm TL and a male 56.80 mm TL). Unfertilized eggs are nearly spindly, opaque yellow in colour, measuring about 3.20-3.50 mm in length, about 1.50-1.80 mm in breadth. Hatching began about 50 hours after insemination at water temperature of $16.5{\sim}18.5^{\circ}C$. The newly hatched larvae are 4.10-4.50 mm in total length(TL), with 29-30 myomeres. Nine days after hatching, the larvae averaged 8.40 mm in total length and caudal notochord flexed at $45^{\circ}$. Eighteen days after hatching, total length reached 8.90 mm. The part of the fin-fold of the future dorsal and anal fins became high. Twenty-eight days after hatching, total length was 9.35 mm. The caudal fin-rays began to fork into two branches. The increased number of melanophores appeared newly on the head dorsal and anal fin-rays. The larvae reached the juvenile stage at 50-60 days after hatching and attained 14.50-16.20 mm in total length, and all fin-rays was formed.

• Korean Journal of Ichthyology
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• v.30 no.2
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• pp.75-83
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• 2018

This study is to observe species identification and early life history of Korean endemic species of Tanakia latimarginata and to use it as a basis for taxonomic studies. As a result of morphological identification, a dark band appeared at the margin of the anal fin, and the ovipositor color of the female was light orange. The shape of the egg was fusiform and sticky. The egg size (long${\times}$short diameter) averaged $4.41{\times}1.44mm$. The incubation time was 126 hours after the fertilization at an average water temperature of $21.0^{\circ}C$. Immediately after hatching, the larvae had egg yolk at an average total length of $5.91{\pm}0.18mm$ (n=5). At 18 days after hatching, the trunk fur was developed in the caudal fin with an average total length of $8.02{\pm}0.08mm$ (n=5). At 41 days after hatching, the larvae absorbed egg yolk at an average total length of $8.70{\pm}0.23mm$ (n=5). At 80 days after hatching, the average length of the fins was $12.6{\pm}0.28mm$ (n=5). The number of fin of the dorsal fin was iii.8, the anal fin iii.9~10, the caudal fin 19, lateral line scales 32~35 were similar to their brood stork.