• 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.4 no.2
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• pp.31-43
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• 1992

The blenniid fish, Entomacrodus stellifer light(Herre) is distributed in the coastal waters of southern Japan and south-eastern Korea. Matured adults of blenniid fish were collected from the rocky shore of Namchun-dong, Nam-gu, Pusan, Korea in July, 1991. The observations were made on the morphology and skeletal development of the reared larvae and juveniles. The lavae reached 5.80mm in mean total length(MTL) in 10 days after hatching. A this time the larvae have absorbed the yolk completely and became postlarvae. Melanophores are distributed on the fin membrane of the lower part of pectoral fin and ventral margins of tail. The larvae averaged 6.20mm in TL and the caudal notochord flex at $45^{\circ}$ in 13 days after hatching. The part of the fin-fold of the future dorsal and anal fins became high. The lavae reached juvenile stage in 31 days after hatching and attained 15.80mm in MTL, and all fin-rays was formed. Ossification of the cranium took place at 6.20mm of MTL(11 days after hatching) in parasphenoid. Vertebrae began to develop from the anterior end to ossify posteriorly. Ossification of all bones nearly completed when the larvae reached to 15.80mm in MTL (31 days after hatching).

• Journal of Aquaculture
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• v.12 no.1
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• pp.15-24
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• 1999

From January 1997 to May, the red marbled rockfish, Sebastiscus tertius (Barsukov et Chen) was reared in the laboratory, and observed the morphological characteristies of egg and development of larvae and juveniles. The egg is spherical in shape colorless and transparent, measuring 0.72~0.80mm in diameter (mean 0.75mm, n=50). The naturally bearing larvae were 3.79~3.97mm in total length with 7~8＋15~16=22~24 myomeres, and mouth and anus were open. Melanophores were present on the yolk of the larva and ventral margins of the tail. The 1~2 days after bearing larvae measured 3.90~4.13mm in total length, and transformed to postlarval stage, and yolk sac were completely resorbed. On the lower jaw melanophores were present. Total length of the larvae was 4.23~4.60mm in total length (11 days after bearing), number of elongated pectoral fin rays was 9~10, and melanophores distributed on the top of head, around the intestine tube, ventral margins of the tail and on the pectoral fin. In 21 days after bearing, the larva were 5.83~7.10mm in total length, and the caudal notochord flex $45^{\circ}$. Individuals of 9.80~12.36mm in total length (33 days after bearing) are regarded to have reached to the juvenile stage with all the fins were developed.

• Applied Microscopy
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• v.29 no.1
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• pp.105-124
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• 1999

Histological and ultrastructural differentiations of the neuroepithelial cells in the mouse embryo during neurulation were observed. The neural plates and grooves consisted of pseudostratified columnar epithelium in the embryonic day (ED) 8 embryo were developed. In the ED 9 embryo, the neural tube was developed in all body length of embryo except both the cephalic and caudal ends. Secondary neurulation was shown at the tail bud of the ED 10 embryo. In the ED 8 embryo, the primitive streak was shown in the posterior end of the embryonic disc. The neuroepithelium, notochord and mesenchyme were well differentiated in the cephalic and cervical portions. In the ED 9 and 10 embryos, the roof plates of neural tubes were constituted of the closing of the surface ectodermal cells in the hindbrain and the neuroepithelial cells in the spinal cord. The floor plate of neural tube were consisted of the low pseudostratified columnar epithelium. The spinal motor nerve fibers were initially differentiated in the ED 10 embryo. According to the electron density of the cell and the differentiation of tell organelles, the neuroepithelial cells in the ED 9 and 10 embryos were classified into three types: dark, intermediate and light types. All types in the ED 9 embryo were observed but the dark cell in the ED 10 embryo was not done. The free ribosomes and polysomes in all neuroepithelial cells were developed. The RER and lipid droplets in the dark cell and the Golgi complex in the intermediate and light cells were observed. Many microfilaments in the cytoplasmic processes of intermediate cell and the microfilaments and microtubules in the light cell processes were observed to be well differentiated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.114-120
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• 1998

The spawning behavior, development of eggs and larvae of the Korea freshwater goby, Rhinogobius brunneus (Temminck et Schlegel) were studied. The eggs were spawned as a one-layer mass, hanging from the underside of a small pebble, and guarded by one male. The eggs were elliptic, about 1.48 mm in length and 0.65 mm in breadth, with a round top and a somewhat flat base with glutinous fibers. Hatching in the indoor tank with $17.0^{\circ}C$ in mean water temperature started from the 146 hours after fertilization. In the late developing stages, the embryo moved and freely changed its head to face the free tip of the chorion (normal egg) or to the basal end with a boundle of adhesive filaments (agrippa egg). Newly-hatched larvae were $3.10\~3.30$ mm in total length (mean: 3.22 mm), and mouth and anus were not yet open. Melanophores were present on the air- bladder, around the anus, and on the ventral part of the caudal region. The larva $3\~4$ days old transformed to postlarval stage, and they were $3.30\~3.85$ mm in total length (mean: 3.60 mm). As yolk sac and oil globules werw nearly absorbed, mouth and anus were open, and they fed rotifers actively. In $20\~22$ days after hatching the larvae grew to 5.85 mm in 71, and the caudal notochord flex at $45^{\circ}$.

• Korean Journal of Ichthyology
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• v.34 no.1
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• pp.25-33
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• 2022

We investigated to elucidate the early life history of siberian stone loach, Barbatula nuda (Pisces: Nemacheilidae). Adult fish were collected using net in the Sangcheoncheon Stream, Cheongpyeong-myeon, Gapyeong-gun, Gyeonggi-do, Korea, 26th April 2020. HCG 10 IU/g was injected to female and male fish and fertilized by dry method in the laboratory. The number of eggs of B. nuda was 1,308±293 (TL: 70.64~79.24 mm), and the egg color was yellowish grey. Fertilized eggs measured 1.13±0.01 mm (n=10) in diameter and showed adhesion. The fertilized eggs started hatching after 104 hours. At the time of egg development, the 15℃ group showed an average hatching rate of 80.1±1.2% and the 20℃ group showed 61.5±6.8%, so the 15℃ group was suitable (p<0.05). Newly hatched larva an average were 3.12±0.06 mm (n=10) in total length. At 4 days after hatching, the total length was 4.89±0.09 mm (n=10), and feeding began with the mouth and anus opened, and entered to preflexion larvae stage. At 21 days after hatching, the total length was 10.98±0.40 mm (n=10), and the distal part of the notochord was bent to 45°, and entered to postflexion larvae stage At 26 days after hatching, the total length was 13.47±0.37 mm (n=10), and entered the juvenile stage.

• Korean Journal of Ichthyology
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• v.34 no.2
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• pp.86-95
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• 2022

Egg development and morphological change of larvae and juvenile of the Roughscale sole, Clidoderma asperrimum, were investigated in the present study. Adult fishes were collected on the East Sea, Korea, from 2017 to 2018 and reared in a circular water tank (Ø 6×1 m) at water temperature of 12.8±1.9℃. Fertilized eggs ranged from 1.42 to 1.59 mm (mean 1.51±0.04 mm, n=50) in diameter. The eggs were spherical in shape, transparent, floating and colorless. The egg yolk was separated from the egg membrane 60 mins post-fertilization (PF), and an embryo was formed in 62 hrs PF. More than 50% of the eggs hatched within 144 hrs PF in the range of 10.2~11℃(mean 10.8℃). The size of the newly hatched larvae were 4.22~4.64 mm (mean 4.53±0.16 mm) in total length (TL), their mouth and anus were not open yet. At 10 days after hatching, the preflexion larvae reached 5.88~6.62 mm (mean 6.31±0.33 mm) in TL, and the yolk absorption was completed and the mouth began to open. At 55 days after hatching the larvae reached to flexion larvae stage and they were 10.4~13.3 mm (mean 12.7±1.3 mm) in TL, and the tip of notochord was bent upward. At 120 days after hatching the larvae reached to juvenile stage and they were 35.3~40.5 mm (mean 39.5±2.4 mm) in TL. Their all fins had completed set of the fin-rays (D. 79~94: A. 63~75) and the juveniles adopted a benthic life.

• 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.

• 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).

• Korean Journal of Ichthyology
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• v.2 no.1
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• pp.53-62
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• 1990

Morphological development from egg to juvenile stages of the trident goby, Tridentigertrigonocephalu5 were observed in the laboratory at Pusan, Korea. The ripe eggs were spherical in shape, measuring 0.49-0.62 mm in diameter. The eggs became ellipsoid shape after the insemination and measured about 1.40-1.58 mm on the long axis. Hatching began about 158 hours after insemination at water temperature of $20.5-24^{\circ}C$. The newly hatched larvae were 2.88-3.14 mm in total length(TL), with 27-28(10+ 17-18) myomeres. Many melanophore and guanophores are distributed on eye cups, gas bladder, optic vesicle, intestine and the caudal region. Three days after hatching the yolk and oil-globule was completely absorbed and the larvae attained a total length 3.26-3.62 mm. The larvae swam actively in the aquarium and fed on the rotifer. Ten days after hatching, the larvae averaged 5.20 mm in TL and the caudal notochord flexed at $45^{\circ}$. Twenty days after hatching, the larvae averaged 7.47 mm in TL and rudimental anal, second dorsal, caudal and pectoral fins were formed. The larvae attained 12.05-12.65 mm in TL thirty five days after hatching and are found to transit the bottom-life, and first dorsal and ventral fins are completely formed. The larvae reached the juvenile stage at 45-50 days after hatching and attained 15.85-16.95 mm in TL, and all scales appeared on the body.