• Environmental Analysis Health and Toxicology
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• v.20 no.1
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• pp.57-65
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• 2005

Effects of five polycyclic aromatic hydrocarbon (PAHs) constituents (naphthalene, fluorine, fluoranthene, benzo(a)pyrene, pyrene) on fertilization and early development of sea urchin egg, sperm and fertilized egg were investigated. The eggs, sperm and fertilized eggs were exposed to several concentrations of PAHs (1, 10, 100, 1000 and 10000㎍/L). The rate of fertilization and hatching decreased when the eggs and sperm were exposed to aqueous solution of PAHs. Also, Exposure of fertilized eggs with each PAHs did decrease survival and hatching rate. Concentration-dependent toxic effects on the rate of fertilization, hatching, survival and abnormality in A. crassispina were observed following exposure to PAHs (1, 10, 100, 1000 and 10000㎍/L). These data show that PAHs exposure decreased in fertilization success of sea urchin egg and sperm and producted abnormal embryo. It is plausible to suggest that PAHs had the potential to significantly reduce coastal recruitment of sea urchin.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.625-633
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• 2020

The effects of temperature and salinity on egg development and settlement of the ascidian Herdmania momus were investigated. Adult specimens were collected from the Dodu Yacht facility in Jeju Island, Korea(33°30'30.54"N, 126°27'55.46"E) in August 2018. Egg development and larval settlement were observed and recorded at 8 h intervals using a stereomicroscope, under nine temperature (10, 13, 16, 19, 22, 25, 28, 31, and 34℃), and four salinity regimens (28, 30, 32, and 34 psu). The highest hatching rate (82.8±7%) was observed at 32 psu and 25℃ and the lowest hatching rate (1.0±2%) was at 34 psu and 13℃. The developmental rate (0.222±0.0994) was highest at 28 psu and 28℃, and lowest (0.016±0.008) at 30 psu and 13℃. The highest settlement success rate (77.1±5%) was at 32psu and 25℃ and the lowest(0.1±1.0%) was at 30psu, and 13℃. The rate of settlement(0.080±0.000) was highest at 28psu and 28℃, and lowest(0.013±0.000) at 30psu and 13℃. Both hatching and settlement success rates increased as temperature increased and tended to decrease beyond an optimal temperature range. Herdmania momus preferred 30-34 psu salinity and 22-25℃ temperature. This study provides baseline information about the life history of H. momus, and important data to control the damage caused by the increase in number and distribution of this invasive ascidian.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.337-341
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• 2001

Studies were conducted to determine the effects of water temperature on the number of spawning, egg production, spawning intervals and hatching success of Chinese bleak, Aphyocypris chinensis. Adult fish were exposed to water temperatures of 19, 22, 25 and $28{\circ}^C$ for two months in the laboratory. The spawning number, egg productivity, and hatching rate increased as water temperature increased between $19{\circ}^C$ and $25{\circ}^C$. Maximum egg production and hatching rate occurred at $25{\circ}^C$, whereas the spawning intervals decreased as water temperature increased except for the treatment of $28{\circ}^C$. The shortest spawning interval observed at $25{\circ}^C$.

• Korean Journal of Ichthyology
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• v.35 no.3
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• pp.151-159
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• 2023

This study investigated the early life history of the Micropercops swinhonis in Botongcheon stream Hangang River and compared the relationship between the related species and flexibility. The fertilized egg of the ovoid type, and the average egg diameter was 1.23 mm in long diameter and 0.85 mm in short diameter. At a water temperature of 20.6℃, the hatching time took 179 hours. The newly hatched larvae measured 3.82~4.08 mm in total length (TL), and their mouth and anus were not yet open. At 18 days after hatching, the postflexion larvae reached 7.97~8.43 mm in TL, with the tip of the caudal fin bent at 45°. At 29 days after hatching, the juveniles reached 9.83~10.8 mm in TL and were differentiated by their constant number of fins (7~10 first dorsal, 10~11 second dorsal, 7~10 anal fins). As a result of the study, there was a difference from the related species in the egg diameter, the newly hatched larva size. The postflexion larvae period and the development period of the first dorsal fin were the slowest among the comparable simila species, and the size was characterized by a large number, indicating a difference from similar species in the early life history process.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.6
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• pp.948-953
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• 2021

To find the optimal eggs to larvae transforming temperature of walleye pollock Theragra chalcogramma, we investigated their hatching pattern, mortality, and larval deformities. Results showed that the hatching quality decreased as the water temperature increased and dropped sharply above 13℃. The highest hatching rate was achieved at 7℃, whereas the lowest was at 15℃. Dead eggs were not observed at 7℃; however, dead egg ratios were significantly high at 4.5℃ and above 13℃ (P<0.05). Mortality of larvae after hatching was not observed at 4.5℃, but was significantly high above 13℃. The DNA content of the larvae did not show any significant difference at all water temperatures; however, RNA content was the highest at 7℃ and was significantly low above 11℃. In addition, RNA/DNA ratio was the highest at 7℃. Larval deformities after hatching were low at 7-11℃ and higher at higher or lower water temperature. Therefore, the hatching index and larval health index of Walleye pollock eggs in this study show that 7℃ to 11℃ seems to be the optimal transforming water temperature range.

• Korean Journal of Ichthyology
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• v.12 no.3
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• pp.208-214
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• 2000

The egg development and morphological changes of larvae of the file fish, Thamnaconus modestus(Gunther), was investigated by artificial insemination. The fertilized egg was spherical in shape, colorless and adhesive with 0.63~0.67mm in diameter and yolk had 20~30 oil globules of various size (0.04~0.16 mm in diameter). The hatching occured at 53 hours after fertilization in $21.0\sim23.0^{\circ}C$ of water temperature. Hatched larvae measured 2.07~2.20 mm in total length with 5~6+17~18=22~24 myotomes. The 3~4 days after hatching larvae grew to the total length 2.62~2.77 mm, opened mouth and anus. The 5 days after hatching, total length of the larvae was 2.74~3.04 mm, the first dorsal fin was formed at the behind of head. After hatching 12~13 days larvae attained 3.78~3.99 mm in total length. This period formed rudimental dorsal fin and anal fin. Twenty days after hatching, larvae grew to 6.04~6.17mm in total length, at which time the dorsal, anal and caudal fin rays reached 19~20, 18~19 and 9~10, respectively.

• Korean Journal of Environment and Ecology
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• v.35 no.3
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• pp.285-293
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• 2021

This study was conducted to elucidate spawning period characteristics and early life development of eight barbel loach, Lefua costata (Balitoridae) at the Jusucheon stream, Okgye-myeon, Gangneung-si, Gangwon-do, Korea between January and December in 2018. The spawning period was estimated to be from May to August, considering the change in the gonad-somatic index, the appearance of young fry, and frequency distribution in egg diameter. It was a multi-spawning type. The gender ratio was 1:0.79 with 1,117 females and 879 males collected. The egg size was 0.24-0.93 mm, with mature and immature eggs found during the spawning period. The size of mature eggs was 0.71±0.02 mm, and the average number of fecundity was 1,786±818 (n=31). Observation of the egg development showed that the fertilized eggs were the sticky, gray, segregated, and demersal type with 0.76±0.03 mm in diameter. The hatching of the embryos began at about 34 hours (hatching rate 50%) after fertilization underwater temperature of 25℃. The average length of the newly hatched pre-larvae was 2.7±0.11 mm. The average length of pre-larvae at 4 days after hatching was 4.5±0.16 mm, and the yolk sac was completely absorbed and entered the post-larvae stage. At 20 days after hatching, the average length of post-larvae was 11.5±0.67 mm, and their fin rays were formed before they transitioned to the juvenile stage. At 100 days after hatching, the average length reached 49.8±2.60 mm, and the appearance and the lateral sideband patterns were similar to those of the adult fish.

• Journal of Animal Science and Technology
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• v.48 no.5
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• pp.671-682
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• 2006

This experiment was conducted to investigate the effects of dietary Ca levels and some feed additives such as isoflavone and casein phosphopeptide (CPP) on eggshell quality and hatching egg production in aged egg-type breeder hens. A total of three hundred and sixty, 56-week-old Hy-Line Brown breeder hens were divided into six groups and fed experimental diets of two levels of Ca (3.3% or 3.6%) either with addition of 0.2% isoflavone, 0.5% CPP or devoid of all for 5 weeks. There were no significant differences in laying performances and settable egg production among the groups. Significant increases (P<0.05) in eggshell strength were observed with increasing dietary Ca and addition of isoflavone, but not with addition of CPP. Fertility and hatchability were not influenced by dietary Ca and addition of isoflavone or CPP. The treatment had few significant effects on tibial proximal compositions and breaking strength. The concentrations of Ca, P, estrogen and calcitonin in serum were not affected by the dietary treatments. These results indicated that relatively high level of dietary Ca in combination with isoflavone had a beneficial effect on improving eggshell quality in aged egg-type breeder hens. But hatching egg production was not affected by dietary isoflavone or CPP.

• 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.

• 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.