• 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 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 $20\sim22mm$.

• The Korean Journal of Malacology
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• v.32 no.1
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• pp.37-43
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• 2016

This study was carried out to determine the optimal water temperature for the embryonic development and laboratory culture of larvae of an intertidal mud snail, Nassarius festivus. The embryos and hatched veliger larvae of N. festivus were incubated at six different temperatures (5, 10, 15, 20, 25 and $30^{\circ}C$). Developmental time for each stage decreased as water temperature increased. The elapsed time to develop to the veliger larva at 15, 20, 25 and $30^{\circ}C$ was 559, 155, 131 and 103 hrs, respectively. At 5 and $10^{\circ}C$, embryo developed to veliger larvae but failed to hatch out of the egg capsule. In contrast, all embryos successfully hatched in the temperature range from 15 to $30^{\circ}C$. The biological minimum temperature during the embryonic development of N. festivus was estimated to be $9.5{\pm}0.4^{\circ}C$. The cumulative water temperatures for blastula, gastrula and veliger stages were calculated as $111{\pm}84$, $486{\pm}185$, $1,164{\pm}72^{\circ}C$, respectively. Temperature also affected the larval survival. Five days after hatching, more than 84% of larvae survived at all experimental temperatures. However, survival began to decrease after 6 days. It was 0% at $30^{\circ}C$. Survival of larvae incubated for 8 days was higher at 15 and $20^{\circ}C$ than other experimental temperatures. We therefore suggest that the optimal range of temperature for embryonic development and larval survival of N. festivus is $15-20^{\circ}C$.

• Korean Journal of Ichthyology
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• v.34 no.2
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• pp.96-101
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• 2022

The egg, larvae, and juvenile development of Platycephalus indicus sampled from Yeosu estuary were conducted. The egg shape of P. indicus is spherical and transparent on the outside, with two perivitelline cavities inside and one oil globule. The diameter of the fertilized eggs were 1.03~1.12 mm (mean =1.08 mm, n =50). The embryos hatched in about 50 hrs 30 mins after fertilization at the water temperature of 20℃. The newly hatched larvae showed a total length of 2.72~3.04 mm (mean=2.93±0.21 mm, n=50). At 5 days after hatching, they were 3.88~4.42 mm (mean=4.11±0.31 mm, n=15) in TL and their yolk was completely absorbed, developing the teeth. They became juvenile 39 days after hatching and reached 10.23~11.95 mm (mean=11.09±0.86 mm, n=5) in TL. At 45 days after hatching, they were 12.01~13.25 mm (mean=12.63±0.62 mm, n=5) in TL, and their body shape and color were similar to those of adult fish.

• 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.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.36 no.3
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• pp.220-229
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• 2024

This study investigated the early life history of Rhinogobius giurinus in the Botongcheon stream and compared the differences with related species. The fertilized egg size (long×short) of the 3.46×1.17 mm (n=30) on average. The time required for hatching at the water temperature of 22.5±1℃ was 213 hours and 30 mins. Immediately after hatching, the egg yolk had an average total length of 2.34±0.05 mm (n=30), and the mouth and anus were not opened, and the number of myotomes was 23~25. 3 days after hatching (DAH), the preflexion larvae had an average total length of 2.70±0.09 mm (n=30), and live food intake began as the mouth and anus were opened. 22 DAH, the flexion larvae had an average total length of 5.26±0.16 mm (n=30), and the tip of the vertebrae began to bend upward. 48 DAH, the postflexion larvae had an average total length of 11.1±0.53 mm (n=30), and the tip of the vertebrae was completely bent 45° upward. 60 DAH the juveniles had an average total length of 14.9±0.69 mm (n=30) was reached to the integer with 6 first dorsal fins, 8~10 second dorsal fins, 9 anal fins, 15 caudal fins, and 5 ventral fins for each fin. As a result of the study, the melanophore differed from other postflexion larvae of the Gobiidae fishes in that it was deposited above the gill lid, on the back and body, and the xanthophore was deposited on the head and body.

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.10-19
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• 2023

This study aimed to examine the early life history of Trident goby (Tridentiger brevispinis) by observing their egg development and juvenile fish morphology. The average size of mature eggs was 1.13~1.41 (1.30±0.07) mm (n=30), and 0.70~0.86 (0.79±0.04) mm (n=30) in long diameter and short diameter, respectively. The incubation period at 24±1℃ ranged from 167~228 h. The newly hatched larvae measured 2.31~2.78 (2.51±0.18) mm (n=30) in total length (TL), and their mouth and anus were not yet open. At 3 days after hatching, the preflexion larvae reached 2.84~3.10 (2.98±0.10) mm in TL, where in their yolk absorption was complete and their mouths began to open. At 19 days after hatching, the larvae reached the flexion stage, measuring 4.02~4.62 (4.36±0.19) mm in TL. The tip of their notochord was bent upward. At 30 days post-hatching, the larvae reached the postflexion stage, measuring between 5.04~6.36 (5.76±0.51) mm in TL, with the tip of the caudal fin bent at 45°. After 54 days, the larvae had reached the juvenile stage, measuring between 7.43~9.84 (8.48±0.90) mm in TL, and were differentiated by their constant number of fins (6 first dorsal, 12 second dorsal, 11 anal, and 10 ventral fins). This study found that T. brevispinis had larger fertilized eggs and a greater number of myotomes in hatching larva than similar species. Additionally, the distribution of melanophores in T. brevispinis was distinct from that in other similar species, making it easy to distinguish them morphologically.

• The Korean Journal of Malacology
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• v.30 no.4
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• pp.303-309
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• 2014

The development of Japanese geoduck, Panopea japonica, grown under culture conditions, has been examined through the morphological characteristics in fertilized egg, larvae and juvenile. Gametes were stripped from ripe broodstock and placed into two separate containers. Eggs were washed through a $40{\mu}m$ sieve and fertilized with dilute sperm solution. Developing larvae were maintained at $19{\pm}1^{\circ}C$. Fertilized eggs with $81.6{\mu}m$ diameter developed to trochophores within 14 h and to D-stage larvae ($116{\mu}m$ shell length) within 27 h. Larvae were spontaneously settled at shell length of $311{\mu}m$ after 20 days. The hatching from fertilized eggs and larval rearing were normally available in $18.5-21.5^{\circ}C$, and the growth was good in a cashmilon substrate, as well as sand. After rearing of day 108 from metamorphosis, the shell length of juvenile P. japonica reached 13 mm, and growth rate of shell length of the juvenile was $117.5{\mu}m/d$.

• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.112-117
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• 2014

The spawning behavior, development of eggs and larvae of the blennioid fish, Dictyosoma burgeri were investigated. The blennioid fish were caught at Hwayang-myeon, Yeosu-si, Jeollanam-do from December 2013. The egg was spherical, measuring from 1.31 to 1.47 mm in diameter. The incubation period of the egg extended from 744 hrs at the temperature varying between 14.5 and $16.5^{\circ}C$. The newly hatched larvae were 7.10~7.60 mm(mean $7.34{\pm}0.18mm$) in total length. Two days after hatching, prelarvae was measured 8.43~8.47 mm (mean $8.45{\pm}0.01mm$) in total length. They began to eat rotifer and transformed to postlarvae stage. Six days after hatching, postlarvae was measured 9.06~9.13 mm(mean $9.10{\pm}0.02mm$) in total length.