• Korean Journal of Veterinary Research
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• v.33 no.3
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• pp.471-478
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• 1993

Culicoides arakawae is a kind of the main blood sucking insects of domestic fowls and serves as a vector of Leukocytozoom caulleryi, the causative protozoon of chicken leukocytozoonosis. In this study, the complete life history of C arakawae was cycled by laboratory colonization. Adult midges were collected from various poultry farm by light trap. The laboratory colonization was performed under the conditions of constant temperature of $25{\pm}1^{\circ}C$ and relative humidity of 80% or above. The hatched larvae were cultured in larval medium consisted of rice field mud and activated charcoal powder. The surface of medium was continuously flowed with biologically conditioned water. The fine powder meal composed of pellet feed for mice and equal mount of yeast was supplied for feeding larvae at every 72 hours. The life cycle completed at $25^{\circ}C$ in 35~35 days ; the period of preoviposition, egg. larval and pupal stage was 2~3, 3~4, 28~30 and 3 days, respectively. The measurements of the eggs, the lst instar larvae, the 4th instar larvae and pupae was $36.28{\mu}m{\pm}1.95$, $13.58{\mu}m{\pm}0.72$, $4000{\mu}m{\pm}1.47$ and $219.95{\mu}m{\pm}6.25$ in $mean{\pm}S.D.$, respectively. In order to confirm experimental colonization of C arakawae in laboratory, the colonized adult midges were allowed to suck blood from chicken infected with L caulleryi. The oocysts and sporozoites could be identified in midguts and salivary grands of engorged midges at 72 hours after blood sucking.

• The Korean Journal of Zoology
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• v.12 no.1
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• pp.29-33
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• 1969

An ichneumon-fly, Megarhyssa jezoensis Matsumura, was found as a parasite of Sirex nitobei Matsumura, a pest insect of the walnut, Juglans sinensis Maximowicz, at Ye-San, Choong-Nam province, middle Korea. The life cycle of Megarhyssa jezoensis was as follows: 1. It occurred three times a year. The adults appear at the end of April to the middle of May (maximum on 5th May) after hibernation, at the beginning to the middle of July (maximum on 10 th July) in the first generatioin, and at the end of September to the end of October (maximum on 8 th October) in the second. 2. The larvae grew from the beginning of May to the end of June in the first generation, from the middle of July to the beginning of September in the second and from the beginning of October to the end of the year in the last. 3. The pupae developed from the end of June to the middle of July and from the end of August to the middle of September. 4. The adults oviposited their eggs on the surface of the host, the larvae in Sirex nitobei growing in the stem of the walnut, and the larvae hatched from the eggs were ectoparasiting the larvae of Sirex to grow and pupate. The parasite hibernated in the pupal stage but the adult which emerged at the early spring stayed in the hole of the walnut stem till the end of April.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.471-477
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• 2008

Development of egg, larvae and juveniles for the Pacific mackerel, Scomber japonicus are described following natural fertilization in the indoor tank of $25^{\circ}C$ water temperature. Following a routine hormone treatment technique for the brood stock, male and female mackerels were artificially matured by intramuscular injections of LHRHa at a dosage of $400{\mu}g/kg$ body weight (BW)+Domperidone at a dosage of $4{\mu}g/kg$ body weight (BW) to induce maturation in a separate aquarium and induced natural spawning. Fertilized eggs were ca. 1.0 mm in diameter; spherical in shape with a single oil globule; pelagic and non-adhesive. Hatching occurs 41 hours after fertilization at $23-24^{\circ}C$. The newly hatched larvae was 3.03 mm in average total length (ATL), the mouth and anus were not open, oil globule located in posterior end of yolk sac, and preanal length was 42.8% of TL. The larvae measuring 2.89 mm ATL, almost absorbed yolk sac and oil globule material in 2 days after hatching, in which the mouth and anus were open. Melanophores, branch or star in shape were observed on the top of head, peritoneal region and along the ventral contour. In 13 days after hatching, the larvae was 6.88 mm ATL, its posterior end of notochord began to flex upward, finfold of caudal fin appeared, jaw teeth were already formed. In 19 days after hatching, the larvae was 7.71 mm ATL completed only caudal fin rays (9+8), and preanal length was 49.4% of TL. In 37 days after hatching, the larvae was 27.4 mm ATL already completed all the fins, and preanal length was 59.9% of TL.

• 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 Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.323-328
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• 1982

Kareius bicoloratus (Basilewsky) is one of the commonly found right-eye flounders and widely distributed in the coastal waters of Korea and Japan. On December 11,1980, the ailthors carried out an experiment to obtain a large number of fertilized eggs from wild adult fish caught by a trawler. The fish were obtained from Maisaka fish market, Shizuoka Prefecture, Japan. The egg is pelagic, spherical in shape and measuring 1.014-1.04 mm in diameter. The yolk as well as the egg capsule is colorless and transparent, and contain no oil globules. The hatching took place in 73 hr 45 min after fertilization at the water temperature $8.0-9.5^{\circ}C$. Newly hatched larvae are 3.09-3.146 mm in total length, with the anus situated in the middle of the body. The marginal fin does not have Pigment cells and myotome number is 17+20=37. Within one day after hatching, the larvae attained 3.77 mm in total length, and there appeared three or four melanophore on yolk sac. When the larvae attained 3.96 mm in total length, melanophores began to appear on the eye ball. Two days after hatching, the larvae attained 4.05 mm in total length, most of yolk material was absorbed, and the caudal fin began to grow at the terminal part of the notochord. When the larvae attained 4.21 mm in total length, mouth and eyes began to move. After 3 days, the larvae attained 4.342-4.394 mm in total length, alimentary canal differentiated, melanophores appeared on the lower jaw and posterior part of the fin membrane. When the larvae attaind 4.576 mm in total length, marginal line of dorsal fin membrane became concave.

• Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.180-194
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• 2024

Mass mortalities of mud crab Scylla spp. larvae due to pathogenic Vibrio spp. outbreaks have frequently occurred in hatcheries. To overcome this problem, probiotics containing Bacillus subtilis bacteria are applied to inhibit pathogenic ones. We tested different doses of probiotic-containing B. subtilis (10⁸ CFU/g) on the Scylla tranquebarica larvae and investigated the microbiota population, including Vibrio. Water quality, larvae development, and crablet production were also monitored. The recently hatched larvae were grown in twelve conical fiber tanks filled with 200 L sterile seawater, with a salinity of 30 ppt at a stocking density of 80 ind/L. Four different doses of probiotics were applied in the larvae rearing, namely, A = 2.5 mg/L, B = 5 mg/L, C = 7.5 mg/L, and D = 0 mg/L, with three replicates. Next-generation sequencing analysis was used to obtain the abundance of microbes in the whole body of megalopa and the water media for larvae rearing after applying probiotics. Sixteen Raw Deoxyribonucleic Acid samples (eight from a whole body of megalopa extraction from four treatments of probiotics defined as A, B, C, D, and eight from water media extraction from four treatments of probiotic defined as E, F, G, H) were prepared. Then, they were sent to the Genetics Science Laboratory for NGS analysis. Ammonia, nitrite, total organic matter (TOM), larvae, and crablet production were monitored. Based on the Next-generation sequencing analysis data, the Vibrio spp. decreased significantly (p < 0.05) than control test (D) in megalopa-applied probiotics at the doses of 2.5 mg/L (A) and 7.5 mg/L (C) and in the water media for megalopa rearing treated with probiotics at the dosage of 5.0 mg/L (F). Ammonia in the zoea stage in B treatment and TOM in the zoea and megalopa stage in B and C treatments were decreased significantly (p < 0.05). It impacts the higher number of zoea survival in treatments B and C. Finally, it results in a significantly high crablet production in treatments B and C. Therefore, the dosage of 5 mg/L to 7.5 mg/L improves crablet S. tranquebarica production significantly.

• Korean Journal of Ichthyology
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• v.17 no.1
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• pp.29-35
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• 2005

Fertilized eggs of Takifugu pardalis (Temminck et Schlegel) were collected on the coast of Jook-do in Tongyong, Korea, from March 1997 to June 1999, and hatched and reared in the laboratory to investigate osteological development of the larve and juveniles. The newly hatched larvae attained a mean of $3.13{\pm}0.05mm$ in total length (TL). Ossification first began in the parasphenoid, premaxillary and dentary. At 5 days after hatching, the postlarvae attained a mean of $3.82{\pm}0.03mm$ in TL, and their sphenotic, prefrontal, preopercle, opercle, maxillary, and articular were ossified. At 15 days, the postlarvae attained a mean of $7.84{\pm}0.06mm$ in TL, their nasal and posttemporal bones were ossified and the hyoid arch completed ossification. Ossification of all bones was completed in the juveniles (mean = $10.21{\pm}0.06mm$ in TL) at 21 days.

• Development and Reproduction
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• v.12 no.3
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• pp.207-213
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• 2008

In order to monitor the developmental features of embryos, larvae, and juveniles of chub mackerel, Scomber japonicus, the fertilized eggs were obtained by artificial insemination. The fertilized eggs were spherical in shape and floated separately. Their membrane and yolk having 1 oil globule were transparent. The transparent eggs, having one oil drop in the yolk, were $0.94{\sim}1.02\;mm$ (mean, $0.95{\pm}0.03\;mm$) in diameter. The fertilized eggs started hatching at 51 hrs after fertilization in $20{\pm}0.5^{\circ}C$ water. The total length of the hatched larvae was $2.52{\sim}3.0\;mm$ (mean, $2.75{\pm}0.04\;mm$). At hatching, the larva, with the mouth and anus not opened yet, had yolk sack, $28{\sim}31$ myomeres and eyes with melanophore. Yolk completely 2 days after hatching and the total length of post-larvae $3.12{\sim}3.63\;mm$ (mean, $3.39{\pm}0.05\;mm$). At the 18 days after hatching, the tip of tail became curved at the end and the stems for pectoral, dorsal, and caudal fins appeared. Juveniles, having all firm rays, was $44.12{\sim}58.72\;mm$ (mean $55.95{\pm}6.74\;mm$) in TL 25 days after hatching.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.1
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• pp.46-53
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• 2010

Spawning behavior and early life history of the tuman river sculpin, Cottus hangiongensis were studied in the laboratory and in the field at Wangpi Stream, Gyeongsangbuk-do, Korea, from January to December, 2007. The spawning ground was in the lower Wangpi Stream, which is a shallow region about 40cm or less in depth. During the spawning period, from March to April, mature males made nest cavities under stone 10 which they led a gravid female. The male and female then turned upside down, and spawning and fertilization occurred onto the ceiling of the nest cavity. After spawning, the male chased the female from the nest and mated with several other females. Fertilized eggs were spherical in shape, demersal, adhesive, transparent and yellow in color, measuring 1.86 mm (1.79~1.93 mm) in diameter. A mean of 17(12~22) various-sized oil globules were counted in the yolk. Granular materials formed a mass in the yolk. Fertilized eggs hatched at 256 hrs, 10 minutes after the morula stage under water temperature of $15.0{\sim}18.0^{\circ}C$. Newly hatched larvae 9.34 mm (9.02~9.69 mm. n=10) in total length (TL) had a large yolk At 14 days after hatching, larvae 11.40 mm (11.07~11.72 mm, n=10) in TL transformed to the postlarval stage. At 41 days after hatching, postlarvae of 18.42 mm (17.31~18.62 mm, n=10) in TL had reached the juvenile stage. The result of this study indicate that Cottus hangiongensis has the spawning ground in the lower stream and the amphidromous life history which is the different from that of Cottus poecilopus.

• Korean Journal of Ichthyology
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• v.18 no.4
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• pp.339-346
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• 2006

In this study we conducted artificial hybridization between two sibling species, Rhodeus uyekii and R. notatus, and observed the morphological characteristics in early developmental stage. The two species showed difference in egg shape having rhombus and club respectively. The morphology of yolk of larva just hatched also showed well specific characteristics, that is the bean chaff type for R. uyekii (U type) and anchor type for R. notatus (N type). The rate of fertilization between female R. uyekii and male R. notatus (UN type) and between female R. notatus and male R. uyekii (NU type) were complete and its hatching rate were very high, 71.6% for UN type and 97.5% for NU type. The differences occurred in the yolk shape of hatched larvae for each combination of hybrids. In the group of UN, U type of larvae were found very rarely, but almost all the larvae showed intermediate shape polarized to NN type. Similar phenomenon was observed in the NU having intermediate polarized to UU, but without any NN type. These hybrids will be analyzed for their external morphology, sex ratio, the function of sexual organ and karyology after they grown up to adult.