• 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.33 no.4
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• pp.262-272
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• 2021

The egg development and early life history of Tribolodon hakonensis that collected from the Seomjin River were studied. The fertilized eggs of the T. hakonensis were slightly adhesive and separated with a yellow yolk and no oil globule. The size of the eggs was an average of 2.89 mm (2.79~2.96) in diameter. Fifty percents of the embryos were hatched in about 63 hrs after fertilization at water temperature of 20℃. The newly hatched larvae showed average 6.92 mm (6.09~7.60) in total length. At 8 days after hatching, they were 13.75±0.67 mm (n=10) in total length and their yolk sacs were completely absorbed, opening mouth and anus (postflexion larvae stage). At 40 days after hatching, they became juvenile and reached 26.99±1.82 mm (n=10) in total length and all their fin rays were formed. At 137 days after hatching, the young fish were 72.63±10.7 mm (n=10) in total length and their body shape, color and behavior were similar to those of adult fish. The size of eggs and the larva after hatching significantly affected the initial growth among groups of genus Tribolodon, and the hatching time of fertilized eggs and the growth rate of the early life history according to the water temperate were different.

• Development and Reproduction
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• v.20 no.1
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• pp.31-40
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• 2016

This study was conducted in order to examine the egg development in red spotted grouper, Epinephelus akaara and the morphological development of its larvae and juveniles, and to obtain data for taxonomic research. This study was conducted in June 2013, and 50 male and female fish were used for the study. One hundred ${\mu}g/kg$ of LHRHa was injected into the body of the fish for inducing spawning, and the fish were kept in a small-sized fish holder ($2{\times}2{\times}2m$). Eggs were colorless transparent free pelagic eggs, 0.71-0.77 mm large (mean $0.74{\pm}0.02mm$, n=30), and had an oil globule. Hatching started within 27 h after fertilization. Pre-larvae that emerged just after hatching were 2.02-2.17 mm in total length (mean $2.10{\pm}0.11mm$), their mouth and anus were not opened yet, and the whole body was covered with a membrane fin. Post-larvae that emerged 15 days post hatching were 3.88-4.07 mm in total length (mean $3.98{\pm}0.13mm$), and had a ventral fin with two rays and a caudal fin with eight rays. Juveniles that were formed at 55 d post hatching, were 31.9-35.2 mm in total length (mean $33.6{\pm}2.33mm$), with red color deposited over the entire body, and black chromophores deposited in a spotted pattern. The number of fin rays, body color, and shape were the same as that in the adult fish.

• Ocean and Polar Research
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• v.28 no.1
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• pp.45-56
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• 2006

This study investigated primarily the toxic effects of bis(tributyltin)oxide (TBT) and DDT (Dichlorodiphenyltrichloroethane) on the mortality of adult Acartia omorii and barnacle nauplii as well as the hatching rate of A. omorii. Subsequently, compound effects of TBT and DDT on the mortality of immature copepods were tested in order to assess whether or not synergistic influence existed in the mixture of sublethal concentration of two pollutants. Mortality of adult A. omorii increased as exposure concentration of DDT increased in the range of from 0.0001 to 1ppm. Egg hatching rate of the copepod showed no distinctive difference in the range between 0.1 and 10ppm, while barnacle nauplii showed abnormal motility of their appendages in the range of 0.0001 to 1 ppm. Mortality of adult A. omorii increased as TBT concentration increased within the range of 1 and 10 ppb, whereas egg hatching rate of the copepod showed no linear response to the same exposure range. Moreover, copepod nauplii were almost motionless even though copepod eggs hatched under the exposure condition of TBT $(0{\sim}10 ppb)$ and DDT $(0{\sim}10 ppm)$, respectively, suggesting that the nauplii are hard to develop into adult stage. On the basis of the sublethal concentration less than the 24-h $LC_{50}$, 0.001 ppm (DDT) and 2 ppb (TBT) were selected to confirm the compound effects of two pollutants on the mortality of immature copepods. Mortality of immature copepods under the condition of mixture of the two pollutants was higher than that in the single exposure condition. This result seems to indicate that synergistic effects of sublethal toxicants can make a more hazardous effect on the survival of immature copepods even though the concentration of single toxicant is not lethal to copepods in the marine environment.

• Development and Reproduction
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• v.18 no.3
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• pp.173-178
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• 2014

In order to monitor the developmental features of embryos, larvae, and juveniles of Oryzias latipes (Temminck and Schlegel), Oryzias latipes was caught in river of Shinduck-dong, Yeosu-si, Jeollanam-do, on May 2011, and experiments were carried out in Ichthyology laboratory at Chonnam National University. The blastodisc step was the first level for natural spawning. The optic vesicle, Kupffer's vesicle, myotome began to appear 75 hours 57 minutes later. After blastodisc development, the pectoral fins were made at 143 hours 37 minutes and the tail was separated started at the same time. Hatching was observed at 167 hours 27 minutes after blastodisc. The total length of the hatched larvae was 4.95~5.10 mm (mean, 5.01 mm), the mouth and anus were opened. Larvae used yolk completely after 3 days after hatching. The total length larvae was 5.45~5.56 mm (mean, 5.52 mm) after 8 days after hatching, and appeared the stems for tail. The stems pectoral, anal fin were showed after 14 days and the stems dorsal, ventral fin were appeared after 19 days. For 35 days after hatching, the total length of larvae 13.95~15.30 mm (mean, 14.64 mm), and at this time, fins and body were transferred like the adult Oryzias latipes.

• Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.228-234
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• 2005

Despite the relatively high production of fingerlings of the olive flounder Paralichthys olivaceus, its larval rearing in terms of first feeding has not been fully analyzed. We evaluated the variations of amino acids and fatty acids of starved larvae over 96 hr after hatching. We also investigated depletion of the yolk and oil globule of starved larvae and those fed the rotifer Brachionus plicatilis. In addition, the optimum size of the rotifers according to the mouth size of the larvae, and the point of no return with delay of the first feeding, were also examined. The amino acids in the egg decreased abruptly during embryo development. At 48 to 72 hr after hatching, the amino acids of starved larvae decreased by $30-40\%$ from the level in newly hatched larvae. The concentrations of fatty acids in newly hatched larvae were lower than those of floating eggs and dropped sharply at 48 hr after hatching, when the yolk disappeared. The starved larvae depleted their yolksacs and oil globules earlier than the fed larvae did. At 84 hr after hatching, rotifers were detected for the first time in the guts of the larvae, which were about 3 mm in total length. The point of no return appeared to be close to the fourth day from the first feeding. For a high survival rate of P. olivaceus larvae, the first feeding should occur before the third day after hatching.

• Journal of Wetlands Research
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• v.17 no.3
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• pp.320-324
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• 2015

This study was executed to know the effect of three differently controlled temperature conditions on Huanren brown frog (Rana huanrensis )'s growth in 2013. We've collected nine Huanren brown frog egg's sacs on Mt. Surak ($37^{\circ}40^{\prime}55.86^{{\prime}{\prime}}N$, $127^{\circ}05^{\prime}19.99^{{\prime}{\prime}}E$) in Seoul. We put those nine egg sacs in the controlled growth chambers under low temperature (LT, $5{\pm}2^{\circ}C$), medium temperature (MT, $10{\pm}2^{\circ}C$), and high temperature (HT, $13{\pm}2^{\circ}C$) conditions with three egg sacs, respectively. We measured the eggs' hatching rate, their hatching periods, and the size of the hatched individuals. The hatching rate was higher in MT (95.6%) and the rates of the other treatments were relatively lower but very similar such as LT (82.2%) and HT (82.6%). The three hatching periods were 10 days at HT, 14 days at MT and 23 days at LT. The body sizes of the hatched individuals were biggest at MT ($7.62{\pm}0.11mm$), smallest at LT ($6.82{\pm}0.10mm$) and medium at HT ($7.19{\pm}0.15mm$) (P-value ${\leq}0.0001$). From our results, we found that the various water temperatures could be very effective to Huanren brown frog eggs' hatch and growth including their body sizes. We suggest if we study more about the growth of Huanren brown adult frogs under similar temperature conditions for a long term period, it must be very helpful for conservation study about metamorphosis rate and size of adult frog as well as we could understand about the amphibians who are adapting to the climate change.

• The Korean Journal of Malacology
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• v.2 no.1
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• pp.10-12
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• 1986

Pettancylus nipponicus (freshwater limpet) collected from the Lake Choon Cheon were cultrued in aquarium and studied in the respects of an egg deposition and the developmental characters of cleavage. The species were collected only in the Lake Uiam and Choon Cheon and easily sampled on the debris like vinyls and cans. Those smooth surfaces were suitalble substrata for attaching. P. nipponicus, about 4 mm in adult, deposited an egg in one calcareous egg-capsule on the aquarium walls, while many eggs are surrounded in a jelly-like egg-envelope in the most gastropods. And another special features was that an egg-capsule was consisted of two valves and the suture was opended as hatching. A diameter of its egg was $55{{\mu}m}$ and the length of an egg capsule was $620{{\mu}m}$ and $510{{\mu}m}$ in long and short diameter, respectively. It took about 8 hours from beginning cleavage to 16-cell stage and about one year to become an adult.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.3
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• pp.108-116
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• 2006

To investigate the factors controlling the spring population of Acartia hongi, egg production, hatching time of egg and predation pressure were measured. Egg production was maintained the superior position between winter and spring. Egg production was positively correlated with not only water temperature when water temperature was below $7^{\circ}C$ but also chlorophyll-a concentration when it was from $7^{\circ}C$ to $21^{\circ}C$. A regressive equation of development time$(D_e,\;day)$ of eggs derived from water temperature$(T,\;^{\circ}C)$ was obtained as $D_e=18.9(T-0.4)^{-1.0}$, showing longer development time at water temperature below $5^{\circ}C$. In Cross Correlation Analysis(CCA) to examine the time-lag relationship among abundances of developmental stages of A. hongi, egg production rate calculated by multiplying population egg production rate by hatching time showed more significant correlation with nauplii abundance than population egg production rate. Therefore, it suggests that hatching time is also recognized by a factor controlling formation of population and especially, in winter, high abundance of egg derived from high daily egg production rate and delayed hatch by low water temperature become the origin of initial spring population of nauplii. Egg predation by Noctiluca scintillans, suggesting a negative factor in formation of A. hongi spring population, was observed. During spring, A. hongi eggs were found in $2.9\sim21.1%$ of individuals of N. scintillans. It was deduced that $1.2\sim49.5%$ of the eggs produced by A. hongi was preyed on by N. scintillans. In conclusion, the factors controlling spring population of A. hongi were regarded as high egg production by winter generation, the delayed development time of egg by low temperature, and egg predation of N. scintillans.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.195-200
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• 2010

A large volume of hatching jar was tested whether it is an effective to hatch fertilized eggs of Pacific cod. The volume of hatching jar did not show any significant differences in survival of the fertilized eggs; 48.3% for the jar of 15 L and 50.4% for that of 42 L. Survival rate of the fertilized eggs in a large volume of hatching jar ranged from 40.0 to 71.2%, which was higher than those of conventional small circular tank. A higher survival could be achieved even though stocking density of fertilized eggs was as high as 5,000 mL/jar. Consequently, the tested hatching jar allowed for incubation of a greater number of eggs with higher survival rate in a much smaller space. In addition, it reduces costs and manpower, and requires a relatively small amount of water per individual unit (6,700 mL/min), and provides a way to incubate multiple rearing groups in a quarantine environment.