• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.76-77
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• 2003

Olive flounder Paralichthys olivaceus larvae and early juveniles were reared for 43 days after hatching in order to observe the effects of starvation during development and metamorphosis. Morphological, histological and biochemical measurements were made to assess the nutritional condition during growth and starvation from pre-matamorphic through post-metamorphic phases. Two groups of fish were compared ; one with sufficient food supply and one under continuous starvation until death. Among morphometric analyses, both ratios of body height at anus/head height and pre-/post-anal lengths appeared to be sensitive to starvation during which substantial reduction was observed within a day of food deprivation. Histological variables as intestinal and rectal epithelial heights and gall bladder volume changed significantly with onset of starvation. The gut epithelial heights of starving fish decreased with advances in starvation, although they fluctuated during mid-metamorphic phase. In contrast, gall bladder volume increased remarkably soon after starvation. Ontogenetic changes in both gut epithelial height and gall bladder volume were evident, those associated with settlement and/or completion of metamorphosis. Abrupt decrease in the RNA/DNA ratios of starving fish were found right after onset of starvation. Even in the fed fish marked fluctuations in its ratios during metamorphosis were observed, evident by decreasing from late-metamorphic to post-metamorphic stages. These findings suggest that a combination of morphologically and histologically sensitive characteristics, and biochemical measurement could be utilized as a measure to evaluate nutritional condition related to starvation in wild olive flounder larvae and juveniles.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.3
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• pp.287-295
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• 2017

Egg development and morphological change of larvae of the Sakhalin sole Limanda sakhalinensis were studied by observing specimens obtained in a rearing experiment from fertilized eggs to the juvenile stage. The wild broodstock was collected in January 2010 and kept in a circular water tank (${\O}1.5{\times}1m$) at a temperature of $14.5{\pm}0.5^{\circ}C$. Fertilized eggs ranged from 0.72 to 0.82 mm ($0.77{\pm}0.07mm$, $mean{\pm}SD$) in diameter. The eggs were spherical, transparent and adhesive demersal. The egg yolk was divided from the oocyte 10 min after fertilization (AF), and an embryo was formed in 36 h AF. More than 50% of the eggs hatched within 133 h AF. The mouth and anus did not open until $3.5{\pm}0.25mm$ total length (TL). At 4, days after hatching (AH), the fish became larvae 3.7 to 4.2 mm ($4.0{\pm}0.36mm\;TL$), yolk absorption was completed and the mouth began to open. The left eye moved upward and the nostril moved to the right at 39 days AH. These post-larvae ranged from 8.0 to 9.9 mm TL ($8.9{\pm}1.33mm\;TL$). At 50 days AH, the fish became juveniles ($12.4{\pm}1.20mm\;TL$) There were 70-72 dorsal fin rays, 55-56 anal fin rays, 11 pectoral fin rays, and 6 ventral fin rays and the juveniles adopted a benthic life.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.203-208
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• 2020

This study was carried out to clarify the larvae and juveniles of egg development and autonomous development of Hemibarbus longirostris from Korea, and to obtain basic data for species conservation and seed production. The shape of the egg was circular and sticky. The average size of the eggs was 2.01 mm (n=10). At 185 hours after fertilization, more than 50% of the total embryos were hatched. The newly hatched larvae had an average total length of 8.10 mm (n=5) and had egg yolk in the abdomen. At 3 days after hatching, the larvae absorbed all egg yolk was average total length 8.64 mm. On the 6 days after hatching, the caudal tip of the notochord started to curve upwards was average total length 10.9 mm. At 70 days after hatching, the average total length 37.9 mm. The number of fins was i 8-10 in dorsal fin, iii 7 in the anal fin, and ii 5 in the ventral fin.

• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.146-153
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• 2000

The development of larvae and juvenile of the smoothskin sculpin (Ocynectes modestus) caught at Pusan brook in May and June 1995 was described. Yolk was completely absorbed when the larvae was about 6.28 mm in average standard length (ASL) with 32~33 myomeres. Flexion of the notochord started when the juvenile was about 7.36 mm in ASL and finished about 9.34 mm in ASL, respectively. Aggregate numbers of all fin rays were completed at over 10.08 mm in ASL, when the larvae reached the juvenile stage. One pairs of flaps were observed on the dorsal surface of the head at 10.08 mm in ASL. The juveniles longer then 14.00 mm in ASL has the same pigment pattern as that of adults. A new Korean name "Min-Ga-Si-Ggeog-Jeong-i" is proposed for this species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.478-484
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• 2008

To elucidate the spawning behavior and early life history of Liobagrus mediadiposalis, mature male and female fish were collected from a branch of the Seomjin River. Spawning was induced by injecting hormones, and then the spawning process and development of fertilized eggs, larvae, and juveniles were observed. Observations of spawning behavior showed that the female established a territory and built a spawning nest, and frequently pressed on the upper ventral part of the male to release her eggs. When spawning was finished, the fish supplied fresh water to the egg mass using their pectoral and caudal fins. Hatching began 189 h 20 min after fertilization at $21.5-23.5^{\circ}C$ (mean $22.7^{\circ}C$). The mean total length (TL) of newly hatched larvae was 7.18-7.39 mm (mean 7.31 mm). Their mouth and anus were already open and they had 14+24=38 myotomes. Eighteen days after hatching, the larvae were 12.71-13.79 mm (mean 13.27 mm) in TL and the yolk sac was absorbed completely. At 35 days after hatching, when all the fin-rays had formed, the juveniles were 15.84-17.92 mm (mean 16.33 mm) in TL.

• Development and Reproduction
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• v.21 no.3
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• pp.287-295
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• 2017

This study was conducted to observe egg and larvae morphological development of carp to obtain basic data for resource conservation and taxonomic research. Brood carp used in the research (total length 67.3-75.5 cm, average $71.0{\pm}3.45cm$) were bred in a circular rearing aquarium ($600{\times}300{\times}100cm$) using a running water system from January to July, 2015. Breeding water temperature was maintained at $23.0-25.0^{\circ}C$(average $24.0^{\circ}C$). Fertilized carp eggs were translucent and globular, and their size was 1.75-1.89 mm (average $1.82{\pm}0.06mm$). Blastoderms formed 10 min after fertilization and reached the two-cell stage 30 min after fertilization. Then, the embryo turned dark and exhibited melanophores, and blood started flowing from the heart across the egg yolk at 42 hrs and 50 min after fertilization. Hatching began 70 hrs and 26 min after fertilization larvae emerged through the egg membrane, starting from the head. The length of prelarvae immediately after hatching was 5.23-5.38 mm (average $5.31{\pm}0.11mm$) the mouth and anus were closed, and the pectoral fin was formed. Postlarvae at 18 days after hatching had a total length of 11.9-13.9 mm (average $12.9{\pm}1.40mm$), separate anal fin and back membranes, and fin ray. Juveniles fish at 35 days after hatching had a total length of 29.9-30.2 mm (average $30.1{\pm}0.13mm$), with the body covered with scales, and the same number of fin rays, color, and shape as their broodstork.

• Development and Reproduction
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• v.24 no.4
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• pp.307-316
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• 2020

The purpose of this study is to observe the early life history of Korean Lefua costata and use the result as basic taxonomic research data for balitorid fish. The fertilized eggs were light green color with completely circle shape and mean size was 1.21±0.06 mm (n=30). Immediately after hatching, the size of the larvae was 2.81±0.11 mm (n=5) in mean length, with egg yolk. On the 3rd day after hatching, the preflexion larvae had a mean length of 4.64±0.09 mm (n=5), and their mouth was opened to start feeding. On the 8th day after hatching, a mean length of the postflexion larvae was 9.43±0.46 mm (n=5), the distal part of the notochord was bent to 45°, and 16 fin rays were developed on the caudal fin. On the 31st day after hatching, a mean length of juveniles was 22.3±0.85 mm (n=5), and the number of fin rays was the same as that of adult fish with (iv8) dorsal fins and (iii8) anal fins.

• 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.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.332-342
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• 2007

Species composition and quantitative and body length composition of the ichthyoplankton were investigated by samples collected from the coastal waters of uljin in January, April, July and October, 2002. During the study, the collected fish eggs were identified as belonging to 7 taxa. The most of dominant species Engraulis japonicus, were accounted for 38.34% of the total fish eggs, followed by Sillago sihama (25.84%). The collected larvae and juveniles were identified into 25 taxa, 18 families, 7 orders. The domninant species Engraulis japonicus accounted for 90.46% of the total larvae and juveniles, followed by Sebastes schlegeli 2.04%. These 2 taxa constituted 92.50% of the total collected larvae and juveniles. The diversity index of species per months of the collected juveniles the coastal water of Uljin, 2002 was 0.0878~2.3855 and the evenness index was 0.0451~0.9300. in case of dominance index was 0.3000~0.9914 against the evenness index. The analyzed species diversity index by the each stations was 0.3035~0.7440 and the dominance index was 0.8919~0.9669 against the species diversity index. The similarity of community structure per season was very high because of the relative difference (0.010), which was the least in Summer and Fall. In addition, the community structure was very similar in state 1 and state 4 out of each stations because the relative difference was the least, 0.139.

• 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.