• Development and Reproduction
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• v.17 no.4
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• pp.369-377
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• 2013

The fertilized eggs of E. septemfasciatus are spherical and transparent with buoyancy at 790 to $890{\mu}m$ (average $821.8{\pm}2.0{\mu}m$) in diameter with 170 to $230{\mu}m$ oil globules (average $192.9{\pm}0.93{\mu}m$). Hatching began approximately 46 and 35 hours after fertilization at $22.0^{\circ}C$ and $25.0^{\circ}C$ water temperature, respectively. The average total length of newly hatched larvae was $1.75{\pm}0.03mm$. Most of the yolk and oil globules were absorbed within 3 to 4 days after hatching. The larvae reached 2.48 to 2.72 mm in total length, and their mouths and anuses opened at 3 to 4 days after hatching. In this time, the mouth diameters of the larvae were 0.209 to 0.238 mm. The larvae reached 3.24 to 4.15 mm in total length at 11 to 17 days after hatching, and began to metamorphose at the time the second dorsal and pelvic spines appeared and elongated. The abdominal cavity was densely lined with melanophores. The larvae reached 5.12 mm in total length at 24 days after hatching.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.53-59
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• 2006

This study was carried out to obtain the biological studies on aquaculture fundamental data for the resources annexation of Miichthys miiuy in terms of the characteristics of the spawning and effect of salinity. The adults spawners in 5 years were TL $72.3\sim89.6\;cm$, BW $3,736\sim8,818\;g$ in female (n=39), TL $47.1\sim81.2\;cm$, BW $716.6\sim6,853\;g$ in male (n=24). The adults size which were suitable for a stable egg collection were $97.9\sim110.2\;cm$ in total length, $9,657\sim13,200\;g$ in body weight. Each egg contained $1\sim5$ oil globules. Also, the highest hatching rate was 96.7% at the one having an oil globules. The highest hatching rate was 87.0% at 30.0 ppt. The fastest time required from fertilization to hatching was 17 hours 24 minutes at 28.0 ppt.

• Development and Reproduction
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• v.18 no.4
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• pp.259-266
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• 2014

The egg development and early life history of Korean spotted sleeper, Odontobutis interrupta which is Korean endemic species from Sora-choen was investigated. The Korean spotted sleeper were caught at Sora-myeon, Yeosu-si, Jeollanamdo, from Korea at May in 2014. The fertilized eggs were $4.23{\pm}0.05mm$ in long diameter and had oil globules. Hatching time of the embryo began about 442 hr 14 min after fertilization under water temperature of $19.5^{\circ}C$. The newly hatched larvae were $4.27{\pm}0.35mm$ in total length and their anus were not yet opened. 3 days after hatching postlarvae was measured $6.20{\pm}0.11mm$ in total length. 10 days after hatching postlarvae was measured $6.69{\pm}0.14mm$ in total length.

• Korean Journal of Ichthyology
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• v.36 no.1
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• pp.10-19
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• 2024

This study investigated the early life history of Hemibarbus labeo from in Wicheon, stream Nakdonggang-River, and compared their characteristics with closely related species. In April 2021, egg formation and development of autonomous fish were observed in fertilized eggs collected at four spawning sites. The size of the fertilized egg was 1.93~2.39 (average 2.22±0.15, n=30) mm. The water temperature was 22.2~24.1°C, and the hatching time took 109~115 hours. Newly after hatching, the total length of the yolk-sac larvae was 7.50~8.80 (average 7.99±0.46) mm, and the mouth and anus did not develop and had difficulty in being yolk. 6 days after hatching, the preflexion larvae were fed with a total length of 9.49~10.2 (9.78±0.23, n=30) mm. 10 days after hatching, the flexion larvae was 9.97~11.9 (10.7±0.72, n=30) mm in total length, and the tail of the vertebrae began to bend. 20 days after hatching, the postflexion larvae was 12.6~15.2 (13.9±0.77, n=30) mm in total length, and the tailbone was completely bent to 45°. 29 days after hatching, the total length of the juvenile was 16.9~19.8 (18.1±0.91, n=30) mm, and the number of fins reached an integer with 10 dorsal fins, 9 anal fins, and 7 ventral fins. The distribution of melanophore, such as the head, the center of the body, and the upper part of the fin, was different from that of the allied species during the postflexion larvae period, so the morphological characteristics could be distinguished.

• Development and Reproduction
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• v.24 no.1
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• pp.63-70
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• 2020

This study aimed to investigate early life of Coreoperca herzi living in Han River and compare morphological differences between different groups during the development in order to provide basic data for relevant taxonomic research. On average, one female individual spawned 541 to 861 eggs (average 701) at once. After 259 hours, the tail broke out of the egg membrane and hatching began. Immediately after hatching, the larvae were average 7.81±0.10 mm (n=5) in total length. 60 days the juvenile was average 35.9±1.30 mm (n=5) in total length. The white spots spread to the rest of the body, rending the same pattern as that on the body of their broodstock fish.

• Journal of Environmental Impact Assessment
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• v.18 no.3
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• pp.123-129
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• 2009

In Korea the population of breeding house swallow is continuously decreasing. In this regard this study was conducted to find out the overall population trend during 2001-2005. The areas of urban and rural sites were separated to estimate population. Also the sites in Yangpyung areas were chosen to compare population density between two sites during Mar-Aug, 2006. The house swallow had two breeding periods and I tried to correlated amount of days of incubation and number of eggs in the nest. After egg hatching the homing behavior also was estimated assuming lack of foods takes longer to bring foods back to the nest. This study signified that a long term study should be conducted for population change and spring arrival time due to climate change in Korea.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.11a
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• pp.154-162
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• 2002

인간이나 환경에 해로운 영향을 주는 지속성 유기오염물질의 독성을 동물플랑크톤 중 요각류를 대상으로 실험하였다. 실험에 사용된 요각류는 장목만에서 주로 가을에 많은 출현을 보인 Acartia erythraea와 늦가을부터 그 다음해 봄까지 우점하는 A. omorli였다. 지속성 유기오염물에 대한 요각류의 독성을 평가하기 위해 3가지의 실험을 실시하였다. 광양만에서 주로 나타나는 5가지 PAHs에 대한 A. omorli 48h-LC50을 구하였고, 온도에 따른 Benzo(a)pyrene과 TBT의 독성의 변화를 Brine shrimp(Artemia)를 이용해 실험하였으며, PAHs 중에서 독성이 강한 Benso(a)Pyrene에 노출된 먹이를 섭취한 Acartia erythraea와 A. omorli의 egg Production, hatching rate, fecal Pellet의 변화를 측정하였다. A. omorli의 48h-LC50으로 조사된 결과 Fluoranthene과 Benzo(a)pyrene의 독성이 강하게 나타난다. 온도실험에서는 동일한 유해물질을 가지고 실험을 하더라도 온도의 변화에 따라 급격한 독성의 차이가 나타날 수 있고, 유해물질간에도 온도에 따라서 나타나는 독성에 대한 특성이 다르게 나타났다. Benzo(a)Pyrene에 노출된 먹이는 요각류의 egg Production, hatching rate, fecal Pellet에 영향을 미치고 있으며, 특히 농도와 실험시간에 따른 부정적 영향들을 보였다.

• Journal of Aquaculture
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• v.21 no.3
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• pp.176-180
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• 2008

This study clarified biochemical overripeness characterization of ovulated eggs of Anguilla japonica and suggested a method maintained overripeness after ovulation for high hatching rates. In maturated Japanese eel eggs, the relationships between fertilization rate and hatching rate, and fertilization and survival rates were measured. DNA contents showed the significantly low 0.653 pg/ug protein in 20% downward hatching rate trial with decrease of hatching rate(P<0.05), whereas RNA/DNA ratio showed the significantly high 1.058 in 20% downward hatching rate trial(P<0.05). And activities of total alkaline protease and ACPase according to the hatching rate groups did not show the significant difference(P>0.05). The protein contents were assayed the significantly high 186.16 ug/mg protein in 20% downward hatching rate trial(P<0.05). However, the overripened eggs had lowed hatching rate, because of stimulate the overripening of normal maturated eggs due to the continuous supplement of protein (vitellogenin). We suggested that need to reduce supplement speed or interception of vitellogenin produced in live for prevent overripeness of maturated eggs after ovulation

• Development and Reproduction
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• v.19 no.4
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• pp.189-196
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• 2015

This study was examined the ovogenesis of Ussurian bullhead, Leiocassis ussuriensis and the morphological development of its larvae and juveniles and to use the results as basic information for the preservation of species and resource enhancement. For artificial egg collection, human chorionic gonadotropin (HCG) was injected at a rate of 10 IU per gram of fish weight. During breeding period, water temperature maintained at $24.5{\sim}26.5^{\circ}C$ (mean $25.0{\pm}0.05^{\circ}C$). The process of ovogenesis reached the two-cell stage in 50 minutes after fertilization. In 73 hours of fertilization the movement of the embryoid body became active state and the larvae began to hatch from the tail through the oolemma. Length of prelarvae were 6.33~6.50 mm long (mean $6.40{\pm}0.06mm$) just after hatching having yolk with their mouth not opened. After thirty eight days of hatching, juveniles were 30.6~32.5 mm long (mean $31.5{\pm}0.65mm$). The color was dark yellowish brown throughout the entire body, and the number of caudal fin rays developed to thirty six perfectly.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.144-149
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• 2018

The eggs are incubated for 18 days through the generator and incubated in the developing incubator. During the developmental period, the weight loss of the fetus is correlated with the ventricular formation, and the proper ventricular formation is also associated with the healthy embryonic hatching and the egg hatching rate. However, in the incubator period of the domestic hatchery, it is a reality to acquire the resultant side by the Iranian standard weight measurement with the experience of the hatchery and the person concerned and the development period without the apparatus for measuring the present weight. As a result, prevalence of early mortality, hunger and illness during hatching are frequent. Monitoring the reduction of weaning weight is crucial to obtaining chick quality and hatching performance with weight changes within the development machine. Water loss is different depending on the size of eggs, egg shell, and elder group. We can expect to increase the hatching rate by measuring the weight change in real time and optimizing the ventilation change accordingly. There is a need to develop a real-time measurement system that can control 10 to 13% reduction of the total weight during hatching. The system through this study is a way to check the one - time directly when moving the existing egg, and it is impossible to control the measurement of the fetal water evaporation within the development period. Unlike systems that do not affect the hatching rate, four load cells are connected in parallel on the Arduino sketch board and the AT-command command is used to connect the mobile phone and computer in real time. The communication speed of Bluetooth was set to 15200 to match the communication speed of Arduino and Hyper-terminal program. The real - time monitoring system was designed to visually check the change of the weight of the fetus in the artificial incubator. In this way, we aimed to improve the hatching rate and health condition of the hatching eggs.