• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.6
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• pp.536-542
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• 1984

Fish eggs and larvae in the western waters of Korea are surveyed during the periods from February to August in 1982. Six species of eggs and forty-two species of larvae are occurred in the survey area. The dominant species occurred during the study periods are Ammodytes personatus, Enedrias sp., Engraulis japonica, Callionymus sp., Gobiidae, etc. Major spawning month and ground of each species are estimated from the data, i.e., occurrence month and abundance of eggs and larvae by survey month and area, as well as the optimum water temperature and salinity for spawning.

• Korean Journal of Environment and Ecology
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• v.38 no.2
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• pp.143-147
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• 2024

This study aimed to determine the egg-hatching period of boreal digging frogs, Kaloula borealis, and investigate whether the incubation temperature affects the hatching period. In this study, the egg hatching was recorded based on the appearance of the tadpole. The results of this study showed that all the eggs hatched within 48 hours after spawning, with 28.1% (±10.8, n=52) hatching within 24 hours and 99.9% (±0.23, n=49) within 48 hours after spawning. The mean hatching rate of tadpoles showed significant differences depending on the difference in water temperature. The mean hatching rate between 15 and 24 hours after spawning was higher at a water temperature of 21.1 (±0.2) ℃ than at 24.1 (±0.2) ℃. The results suggest rapid hatching occurs at relatively low water temperatures because the spawning habits that spawn eggs in temporary ponds or puddles in the rainy season require rapid hatching before the puddles dry out. The results of this study are helpful for understanding the most suitable temperature conditions for the incubation of eggs of the endangered species, boreal digging frog.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.133-134
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• 2003

This study was conducted to develop ornamental bird granule-type feeds for shortening working hours and improving productivity at the bird farms. We developed two kinds of Common finch feeds for the growing and layer birds. The ME level was 3,200 kcal/kg, respectively and the CP was 16and 20 ％, respectively. The developed feeds and traditional mixed-seed feeds were compared to investigate the egg production and hatching rate in Common finch. There was no significant differences between the two feeds indicating that the developed feeds can be used at the bird farms. However morphological shape changes of the developed feeds will be needed for effective assumption.

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.177-183
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• 1999

This study was conducted to observe the spawning behavior and early life history of chinese minnow, Rhynchocypris oxycephalus reared in the laboratory. The spawning period of Rhynchocypris oxycephalus is from May to June in nature. The eggs of Rhynchocypris oxycephalus were spawned on the sand and surface of the gravel. The fertilization eggs were demersal in shape and adhesive, released as a clump forming a thin layer and their diameter were 1.70~1.90mm (mean 1.80 mm, n=20). Hatching of eggs was started in 88 hour 45 minute after fertilization at water temperature $19{\pm}0.5^{\circ}C$ and finished in 90 hour. Newly-hatched larvae were measured 4.87~5.02 mm in total length (TL, mean 4.94 mm), mouth and anus were not opened. 6 days old larvae were 6.32~6.56 mm in TL (mean 6.44 mm). Yolk sac was almost absorbed, mouth and anus was began to open. 13 days old larvae were 6.74~6.91 mm in TL (mean 6.82 mm). Part of Dorsal fin was began to rising and myomere number was 15+23=38. 25 days after hatching, total length of larvae was 8.45~8.60 mm (mean 8.52 mm). Dorsal and anal fin rays became differentiated, and also caudal part of the notocord flexion was achieved at $45^{\circ}C$. In the time, growth rate was higher than the other stage. Aggregate numbers of all fin rays were completed at 16.39~16.57 mm in TL (60 days after hatching), at which time the larvae reached the juvenile stage, but fin-fold on ventral was remained yet. External features of adult specimens were almost completed at 80 day old juveniles (18.69~18.87 mm in TL).

• Development and Reproduction
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• v.15 no.2
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• pp.133-141
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• 2011

The marine ornamental industry has become a multi-billion dollar industry these days. As developing, however, this industry has been criticized for the indiscriminate captures and the destruction of the surrounding environment. To circumvent these problems, it is suggested to breed the organisms artificially. While clownfishes Amphiprion sp. and Premnas sp. are the most famous ornamental organisms in the trade, few studies are yet available on the culture and commercial production of these fishes. These studies were performed to investigate the spawning periodicity, behavior and the habits during egg incubation, and to provide the information on the mass hatching system. The spawning periodicity and frequency were different in 4 pairs under the constant condition, temperature, salinity and photoperiod. On the contrary, the male's behaviors for egg incubation are almost same in the all. The egg-fanning activity of the male increased as the developing eggs reaching to the hatching day. Based on the above results, we designed a new artificial hatching system, the rotating type (RT), and compared it with the aeration type (AT) and spray type (ST) that were previously described. RT showed higher hatching rate of 87.3% than AT (74.4%) and ST (60.5%). Also, there were no significant differences in the hatching rate regardless of the number (2, 3, 5) of hatching plates. We suggest RT may accommodate various number of hatching plates and constitute a better hatching system for clownfishes.

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.225-231
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• 2004

An endoparasitoid wasp, Cotesia plutellae, has been used for a biological control agent against the diamondback moth, Plutellae xylostella. It has a symbiotic polydnavirus in their reproductive tract, which is required for its successful parasitization. Here, we measured a specific replication time of the polydnavirus during female development of C. plutellae. We, also, analyzed the reproductive potentials of female C. plutellae under mating or different host conditions. At $25^{\circ}C$, pupal C. plutellae began to develop adult tissues such as compound eyes and wings since day 2. At day 5, all adult tissues including antennae were developed and were ready to emerge. With polyclonal antibody raised against C. plutellae polydnavirus, an immunobloting could confirm virus replication at day 4 during pupal stage. Virus particles could be visualized by transmission electron microscope in the oviduct lumen of day 5 pupae. After adult eclosion, venom gland and ovarian calyx increased in size, though ovarioles did not. Mated females layed large number of eggs (over $60\%$) at first 4 days during their mean longevity of ca. 8 days at $25^{\circ}C$. Unmated females showed less active ovipositional behavior, where all the eggs developed into males. C. Plutellae parasitized both P. xylostella and fall webworm, Hyphantria cunea. However, C. Plutellae developed faster and showed higher successful paarasitization in P. xylostella than in H. cunea.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.51-51
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• 2003

대농갱이는 체형이 동자개와 비슷하나 지금까지 인공부화는 물론 산란습성에 관해서도 잘 알려져 있지 않은 미개발 어종으로 양식품종의 다양화 및 경쟁력 있는 새로운 품종 개발을 위하여 인공종묘생산 시험을 시도하였다. 본 연구에 사용한 대농갱이 친어는 금강 중류역에서 서식하고 있는 자연산 친어로 암컷 210마리, 수컷 148마리를 사용하였다. 호르몬주사에 의한 인공 배란효과 조사를 위해 암컷 한 마리당 HCG 1,000 IU 주사군(75마리)과 2,000 IU 주사군(135마리)으로 나누어 배란율을 조사하였으며, 수컷은 주사하지 않고 정소를 적출하여 막자사발에 갈아서 등조액과 혼합하여 사용했다. 수정 방법은 난을 착출하면서 정자 등조액을 동시에 흘리는 방법, 난을 그릇에 받은 후 정자 등조액을 혼합 수정하는 방법, 채란용기에 정자 등조액을 미리 넣고 암컷의 난을 짜 넣어 수정시키는 방법 등 3가지 방법을 사용하였다. 부화된 자어는 초기먹이로 알테미아(3일 급이), 실지렁이(6일 급이), 배합사료 순으로 급이하였으며 수온 25~28$^{\circ}C$에 유지관리하면서 성장도 시험을 실시하였다. 호르몬 주사에 의한 배란효과는 HCG 2,000 IU 주사군(채란율 88.9%)이 1,000 IU 주사군(37.3%)에 비해 월등히 높았으며 난의 성숙상태도 좋았다. 수정방법에 있어서는 채란과 동시에 정자 등조액을 흘려 수정시키는 방법과 채란용기에 미리 정자 등조액을 넣고 암컷의 난을 한 마리씩 짜서 수정한 후 바로 부화지로 이동하여 고르게 뿌려 준 경우가 수정율 및 부화율이 좋았다. 부화수온은 23$\pm$1$^{\circ}C$에서 96시간, 26$\pm$1$^{\circ}C$에서는 72시간만에 부화되었으며 부화여건이 좋으면 단시간에 부화할 수 있도록 하는 것이 수생균 발생을 억제할 수 있어서 효과적이었다. 자치어의 성장도 실험에서는 사육수온 25~28$^{\circ}C$에서 직선식으로 나타낼 수 있어서 평균체장은 Y=0.9943X+0.7867, 평균체중은 Y=0.8800-0.6800로 각각 표시되었다.

• The Korean Journal of Ecology
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• v.1 no.2
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• pp.44-48
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• 1977

The spawning behavior and developmental pattern of the Korean eleotrid fish (Odontobutis obscurus) was investigated in one of the tributary of Han River. The spawining of this species begins on April and continues up to August, whereas, the spawning. of same species were between the end of June and the middle of July in Kyushu, Japan. August The spawning places were the margin of river, its the bottom composed of sand and pebble (Table 5). The velocity of water in the spawning places was 0-40cm/sec, and the depth of waters was 10-40cm. The egg was spawned on underside of stone in the spawning places with one or two folds and ellipsoid in shape, 3.4mm in long diameter and 2.0mm in short diameter. The yolk is 1.2mm in diameter and yellow in color. For hatching of the egg, it takes one month in, $16^{circ}C~19^{\circ}C$ water, in Japan, whereas it takes only 14 days in $20^{circ}C~30^{\circ}C$ wate rin the study area. The growth rate of larva and juvenile fish were as follows: new hatched larva is 45mm in length; after 5 days it became 5.0 to 5.5mm in length and 1.2 to 1.5mm in height after 20 days. it became 11.0mm in length and 2.3mm in length. The mean size of the mature female is 110mm in total length and larger 10mm than that of the same fish found in Japan.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.136-143
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• 2003

The eggs of Favonigobius gymnauchen attached on the under side of a small stone were collected off Seongsan-eup Cheju-do in August, 2000 to investigate their development of egg, larvae and juveniles. The fertilized eggs were elliptical in shape (mean long axis: 1.50 mm; mean short axis: 0.57 mm) and transparent. There were filaments on one side of the egg membrane. Larvae hatched at 48 hrs 50 mins after morula stage with 25-26 myotomes in $22.8-28.5^{\circ}C\;(mean\;24.7^{\circ}C).$ The newly hatched larvae were 2.31-2.49 mm (mean 2.37 mm n=10) in total length (TL) and their mouth and anus were already opened. Their melanophores were appeared on the over gas globule, around anus and the part of caudal peduncle with 24-25 myotomes. At 4-5 days after hatching. larvae attained 3.81-4.07 mm (mean 3.96 mm, n=10) in TL and their yolk sac was completely absorbed. They began to eat rotifer and transformed to postlarvae stage. At 14 days after hatching, postlarvae attained 6.17-6.31 mm (mean 6.21 mm, n=10) in TL and their caudal notocord was flexed $45^{\circ}$ upward. At 24 days after hatching, postlarvae attained 8.69-9.10 mm (mean 8.87 mm, n=10) in TL had reached the juvenile stage. All fins were formed with the complete set of fin rays with the following counts: dorsal fin rays IV-I, 9-10; anal fin rays I, 9; pectoral fin rays 17; ventral fin rays: I, 5; caudal fin rays: 9+8= 17.

• 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 $45^{\circ}$.