• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.478-484
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• 2008

To elucidate the spawning behavior and early life history of Liobagrus mediadiposalis, mature male and female fish were collected from a branch of the Seomjin River. Spawning was induced by injecting hormones, and then the spawning process and development of fertilized eggs, larvae, and juveniles were observed. Observations of spawning behavior showed that the female established a territory and built a spawning nest, and frequently pressed on the upper ventral part of the male to release her eggs. When spawning was finished, the fish supplied fresh water to the egg mass using their pectoral and caudal fins. Hatching began 189 h 20 min after fertilization at $21.5-23.5^{\circ}C$ (mean $22.7^{\circ}C$). The mean total length (TL) of newly hatched larvae was 7.18-7.39 mm (mean 7.31 mm). Their mouth and anus were already open and they had 14+24=38 myotomes. Eighteen days after hatching, the larvae were 12.71-13.79 mm (mean 13.27 mm) in TL and the yolk sac was absorbed completely. At 35 days after hatching, when all the fin-rays had formed, the juveniles were 15.84-17.92 mm (mean 16.33 mm) in TL.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.86-93
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• 1999

Artificial fertilization of flounder, Limanda herzensteini caught at Pohang brook was performed in April 13, 1995 and hatched larvae were reared for 25 days to describe the development of eggs and the morphogenesis of larvae. The fertilized egg was buoyant, colorless and spherical in shape, measuring 0.86~0.96 mm in diameter (mean: 0.90 mm), The egg has no oil globule, and its perivitelline space was narrow. Hatching in the indoor tank with $16.0^{\circ}C$ in mean water temperature started from the 64 hours after fertilization. The newly hatched larva, measuring about 2.80 mm in total length, had 10~11+25~27=35~38 myomeres. The anus is open at about the anterior point of the body. The 3 to 4 days old larva was 3.90 mm in total length. In this larva the eyes were black and the mouth was open. The yolk was consumed in 8 to 9 days. In 20 to 22 days after hatching, the larvae grew 6.1 mm in total length. The eyes were located symmetry on both sides of head.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.6
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• pp.380-386
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• 2007

Egg development and juvenile growth of the Pacific cod Gadus macrocephalus (Korean East Sea Population) were studied to increase fry production using mass cultivation. The eggs were rectangular and adhesive sinking type. The egg size and fertilization rate were 1.01-1.09 mm and 72.4%, respectively. The cumulative times for egg hatching at 3, 6, 9, and $12\;^{\circ}C$ were 600, 360, 240, and 192 hrs, respectively. The hatching rates at 3, 6, 9, and $12\;^{\circ}C$ were 60.2, 68.9, 62.5, and 40.6%, respectively. After 11, 45, and 90 days, the larvae grew to a total length of 5.46-5.99, 9.42-10.06, and 23.0-32.0 mm, respectively. At 100 days from hatching, they grew to an average of 30 mm with a 7.1 % survival rate. By 312 days, juveniles with a total length of 3.6 cm grew to a total length of 14.7-20.1 cm and a body weight of 38.4-73.9 g. The specific growth rates of total length and body weight of the juveniles were 0.50% and 1.12%, respectively.

• Korean Journal of Ichthyology
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• v.21 no.1
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• pp.15-22
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• 2009

An artificial breeding method was carried out to investigate development of eggs and the early life history of Iksookimia longicorpa. The eggs of the female were obtained by injecting gonadotropin (LHRH) and fertilizingby the dry method in the laboratory. The mature eggs were separate, demersal, light yellowish, and averaged $1.53{\pm}0.07mm$ in diameter. In water temperature of $23{\sim}25^{\circ}C$, the eggs hatched in 50~72 hours after fertilization, and their lengths reached $5.1{\pm}0.23mm$ in total length. On Day 4 after hatching, they averaged $7.1{\pm}0.47mm$ in total length and their yolk sacs were completely absorbed. From 25 days after hatching, they attained a juvenile stage reaching $12.8{\pm}0.49mm$ in total length. On the 100th dayafter hatching, their band patterns and external form were similar to those of adults, and they averaged $38.5{\pm}2.95mm$ in total length.

• Journal of Aquaculture
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• v.21 no.4
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• pp.234-238
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• 2008

We studied the effects of temperature and salinity on the egg development and hatching rate of chub mackerel Scomber japonicus under laboratory culturing condition. The fertilized eggs were transparent, spherical, separate in shape and turned out to be separately and floated, and they contained one oil globule. Fertilized eggs are $0.91{\sim}1.33\;mm$ in diameter. The time of egg development was positively proportional to water temperature with 70 hrs, 48 hrs, 42 hrs, 34 hrs, after fertilization in $16^{\circ}C$, $20^{\circ}C$, $24^{\circ}C$, $28^{\circ}C$, respectively. Hatching rate was highest with the range of $20{\sim}24^{\circ}C$ and $33{\sim}35\;psu$. 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 $6.9^{\circ}C$.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.104-110
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• 2008

The egg development and early life history of Korean endangered natural monument fish, Iksookimia choii, were investigated in 2006. The eggs from the females were obtained by injecting 10 IU $g^{-1}$ of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were $1.1\sim1.3mm$ in diameter and had no oil globules. Hatching of the embryo began about 24 hrs after fertilization under water temperature of $25^{\circ}C$. The newly-hatched larvae were $2.5\sim2.7mm$ in total length (TL), and their mouth and anus were not yet opened. Six days after hatching, the postlarvae were $4.7\sim5.4mm$ TL, and tip of the caudal notochord was flexed $45^{\circ}$ upward. The juveniles stage was reached when all fin-rays were formed at 35 days after hatching, and their total length were $20\sim22mm$.

• Korean Journal of Ichthyology
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• v.21 no.4
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• pp.227-238
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• 2009

The egg development and morphological changes of larvae, juveniles and adults of Oryzias dancena were observed. Fertilized eggs were incubated at $25{\pm}1^{\circ}C$; the process of embryonic development was observed by light microscopy and based on diagnostic features of the developing embryos. The average time to hatch was 11 days after fertilization. The hatched larvae averaged $4.40{\pm}0.24mm$ in total length (TL). The yolk sacs of the larvae were almost absorbed at 3 days after hatching and $4.55{\pm}0.23mm$ TL. At 21 days after hatching, the larvae were $7.23{\pm}0.73mm$ TL and had reached the juvenile stage. First ovulation was about 9 weeks after hatching and at $22.58{\pm}2.73mm$ TL.

• Korean Journal of Ichthyology
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• v.34 no.1
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• pp.16-24
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• 2022

The eggs development and early life history of Sarcocheilichthys variegatus wakiyae was investigated. The adult fishes were collected in Yeongsangang River, Damyang-gun, Jeollanam-do, Korea, and their spawning inducement was carried by sex maturation hormone (Ovaprim) injections. Spawning amount was mean 31±3.5 Mature eggs were cicular in shape and mean 2.40±0.05 mm in diameter. Hatching period of the embryo was 230 to 240 hours after fertilization under water temperature of 22℃. The newly hatched larvae were 10.7±0.19 mm in total length (TL). 3 days after hatching, postlarvae was measured 12.0±0.13 mm in TL and the tip of the caudal fin was bent at 45°. 11 days after hatching, it was measured 14.6±0.13 mm in TL, and transferred to juvenile as the number of fins (iii7 dorsal fin, iii6 anal fin, i7 ventral fins) reached a constant number of each part.

• The Korean Journal of Zoology
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• v.24 no.1
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• pp.27-37
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• 1981

Protein patterns at various stages of pre-and post-fertilization in Drosophila melanogaster were analyzed using polyacrylamide gel electrophoresis. Ovaries at various times after hatching, embryos, larvae and pupae were collected and used for protein analysis. The protein patterns were found to vary qualitatively and quantitatively during oogenesis as well as during embryogenesis and metamorphosis. Yolk proteins, which were found to be synthesized in fat body and transferred into the oocytes, appeared in three bands in the gel in the early stages, but these proteins seemded to be converged into a single band in the late stage of oogenesis. The protein patterns in the post fertilization stages seemed to be abruptly changed at two different stages; between embryonic and larval stages and between the second and third instar stages. The pattern in the pupal stages was not very much different from that of the third instar.

• Journal of Aquaculture
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• v.7 no.3
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• pp.159-164
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• 1994

All-female diploid Paralichtlrys olivaceus populations were produced by the artificial fertilization with the normal eggs and gynogenetic diploid males sperms. All-female triploids were also conducted to the fertilized eggs by cold shock. Floating, fertilization and hatching rates of the all-female diploid eggs were not significantly different from that of the diploid control eggs (P>0.05). All-female triploids were also not significantly different from their diploid controls or all-female diploid groups (P>0.05) in the floating and fertilization rates of eggs. However, hatching rates of all-female triploid groups were lower than that of the control (P<0.05). Induction of the triploids were confirmed by the measurement of erythrocyte sizes and by the chromosome counts. The volumes of erythrocytes and nucleus of triploid were larger than those of diploids, respectively. Percent incidences of triploid were $92.6\%$ in this experiment. The chromosome number of diploids and triploids showed 2n=48 and 3n=72, respectively, and their karyotypes were consisted of all acrocentric chromosomes. The gonads of 4-month-old triploids were histologically sterile.