• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.1
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• pp.27-31
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• 2001

To investigate the food organisms and feeding selectivity of the white croaker (Argrosomus argentatus) during the postlarval stage, the gut contents of the postlarvae, captured in Kwangyang Bay in 1995, were observed, The food organisms were composed of copepod egg and nauplius, Codonellopsis sp. and Tintinnopsis spp. The indices of relative importance indicated that the most dominant food item was a copepod nauplius. As white croaker larvae grew, the size of prey items and the selectivity for copepod nauplius increased.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.4
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• pp.450-455
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• 1996

To investigate the food organisms of the shad (Konosirus punctatus) during the postlarval stage, the gut contents of the shad, captured in Kwangyang Bay in June 1990, were observed. The food organisms food items of the shad larvae of $4.8\~5.0mm$ (NL) were copepod eggs and copepod nauplii, whereas those of the larvae longer than 5.0 mm (NL) were copepod nauplii and Tintinnopsis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.495-500
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• 1992

The relationship between distribution of eggs and larvae of anchovy, Engraulis japonica, and environmental factors were studied using the data on the ichthyoplankton and zooplankton sampled vertically by net, and water temperature and salinity observed by CTB in the eastern waters of Korea in every two month in 1985. Anchovy eggs and larvae were occurred in June and August. They distributed in the warm water current which was high temperature and salinity in June. Egg and larval distribution area were moved to the offshore in August. It is likely that distribution of anchovy eggs and larval in June significantly correlate with hydroconditions in the eastern waters of Korea.

• Korean Journal of Ichthyology
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• v.1 no.1_2
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• pp.73-82
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• 1989

The development of eggs and larvae, and minute scale-like tubercles on the skin surface of the larval Acanthorthodeus asmussi from Korea were observed in the laboratory. The egg was nearly ovoid-shaped. The number of egg averaged 195 per an oviposition. The morphological character of larval development was relatively similar to those of Acheilognathus tabira tabira, A. tabira subsp. (a), A. yamatsutae, A. moriokae, A. cyanostigma and A. rhombeus. The larvae of this species had many scale-like tubercles ellipsoided in a diagonal cross section on the skin surface of the body. And also this species moved like incessant wiggly movement pattern as that of fly maggot duing the larval development. As regards the tubercles and larval movement pattern, the larvae of A. asmussi shared similar characters with those of Acheilognathus rhombeus, A. longipinnis and Pseudoperilampus typos. Hence A. asmussi may be closely related to these species. The latter three species are autumn-spawning bitterlings and the larval development always retard in a certain stage, while A. asmussi is a spring-summer spawning species and the larval development never retards. Judging from these facts, it should be considered that there are close relations in evolutionary trend between the two spawning species.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.58-59
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• 2003

연안정착성 어류인 쏨뱅이는 대부분의 볼락류와 더불어 자어를 출산하는 종이다. 그러므로 종묘생산을 원활히 수행하기 위해서는 건강한 자어를 안정적으로 확보하는 것이 무엇보다 중요한 요소이다. 이번 실험은 쏨뱅이 어미를 실내사육하고 자어 출산을 유도하여, 우량의 자어를 다량 확보할 수 있는 기초를 마련하고자 출산시기, 출산횟수, 자어마리수, 자어크기 등 쏨뱅이의 출산생태에 대하여 1997년부터 1999년까지 3년간 실내 자연출산에 관한 연구를 실시하였다. 1. 쏨뱅이 어미의 출산횟수. 쏨뱅이는 한 마리의 어미가 수회에 걸쳐 자어를 출산하는 것으로 알려져 있다. 1997년에서 1999년까지 전년 12월에서 4월까지 쏨뱅이 출산기간동안 출산횟수를 조사한 결과 1997년에는 24마리의 어미 중 총 8마리의 어미가 출산에 가입하였고, 이중 5마리는 1회 출산이 이루어 졌으며, 2마리는 2회, 1마리는 3회 출산이 일어났다. 1998년에는 24마리의 어미를 수용하여, 6마리의 어미에서 출산이 이루어 졌으며, 이중에 4마리가 1회만 출산하였고, 각각한 마리가 2회와 4회 출산하였다. 전장 23.6cm(체중 244.7g)의 쏨뱅이 어미는 총 4회 출산하면서 215,000마리의 자어를 나누어 낳았다. 1999년에는 21마리의 암컷 중 11마리가 출산하였다. 이중 9마리가 1회 출산하였으며 2마리가 2회 출산하였다. 종묘생산 된 쏨뱅이를 대상으로 자어 출산을 조사한 결과 만 2년어부터 출산에 가입하고 있었으며 출산기간동안 1회 출산하였다. 2. 출산자어의 마리수. 1997년과 1998년에 각각 24마리, 1999년에 31마리의 쏨뱅이 어미를 이용하여 출산자어 마리수를 조사하였다. 1997년 쏨뱅이 어미(전장 19.2~23.9cm, 체중 150.0~354.0g)에서 1회 출산 할 때마다 18,000~46,000 마리의 자어를 출산하였다 . 마리당 총출산량은 20,000~56,000 마리 였다. 1998년 쏨뱅이 어미 (전장 19.2~24.7cm, 체중 144.3~317.9g)는 1회 출산에 8,000~90,000마리의 자어를 출산하였고, 마리당 총출산량은 8,000~215,000 마리의 자어를 낳아서 개체에 따라 큰 차이를 나타내었다. 1999년에는(어미 : 전장 20.7~25.5cm, 체중 205.5~396.4g) 1 회 출산때마다 7,000~50,000 마리의 자어를 출산하였다. 3. 출산간격. 다회 출산한 쏨뱅이 어미가 첫 번째 출산에서 다음 출산까지 소요되는 기간을 조사한 결과 13일에서 25일이 걸리는 것으로 나타났다. 특히 4회 출산 한 1998년 쏨뱅이 어미는 첫 번째 출산 후 19일만에 두 번째 출산이 이루어 졌고 각각 13 일과 14 일만에 세 번째, 네 번째 출산이 이루어져 총 46일 동안 4회에 거쳐 자어를 출산하였다. 4. 출산자어의 크기. 1997년 3회 출산한 쏨뱅이의 출산시기별 자어 크기를 조사한 결과 첫 번째 출산에서는 평균전장 4.1$\pm$0.07mm의 자어를 낳았으나 두 번째 출산에서 자어의 크기는 평균전장이 3.9$\pm$0.11mm, 세 번째 3.8$\pm$0.12mm로 점차 작은 경향을 나타내었다.

• Korean Journal of Ichthyology
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• v.28 no.3
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• pp.164-174
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• 2016

Tanakius kitaharae and Glyptocephalus stelleri, belonging to the family Pleuronectidae, were very similar in external morphology not only during adult periods, but also during larval periods. In this study, we compared larval development and growth of the two pleuronectids species in detail. Fifty-eight specimens of T. kitaharae larvae and five specimens of G. stelleri larvae were collected from the East Sea, southern Korean Strait, and the adjacent waters of Jeju Island during 2014~2016, and were identified using morphological and molecular markers. Flexion larvae of T. kitaharae (10.23~16.77 mm total length, TL) and G. stelleri (14.33 mm TL) were similar in morphometrics, but can be distinguished by the melanophores in the fin membranes (present in the former vs. absent in the latter), and the melanophores at posterior margin of shoulder girdle (absent in the former vs. present in the latter). Postflexion larvae of T. kitaharae (17.12~24.92 mm TL) and G. stelleri (27.71~32.95 mm TL) differed in the number of melanophores on the mid-lateral caudal region (two in the former vs. five in the latter), and that on the dorsal and anal fin pterygiophores (five or six in the former vs. one row in the latter). Tanakius kitaharae and G. stelleri larvae differed in size at the beginning of metamorphosis. The left eye of T. kitaharae larvae between 23.13~24.92 mm TL reached the dorsal margin of the head while that of G. stelleri larvae between 38.66~42.67 mm TL did not reached yet.

• Journal of Aquaculture
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• v.11 no.4
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• pp.565-572
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• 1998

Survival rate of larval red spotted grouper, Epinephelus akaara is very low, because mouth size of the larvae is too small to eat normal sizes of rotifers. In order to enhance larval survival, optimal culture conditions for larvae using different live foods and water temperatures were studied. Bigger live food produced larger size of rotifer, when the rotifer was cultured with three different live foods such as Tetraselmis tetrathele, marine Chlorella and Nannochloris oculata. Also, the size of rotifer produced was temperature-dependent showing that higher water temperature induced smaller rotifer. Survial rate of the larvae increased with the increase of water temperature up to $29{\circ}C$. Also, higher larval survials were found at the food density of 15 to 20 individuals per milliliter. The larvae fed L-type or small individuals of L-type rotifer died all within a week, although the larvae fed S-type or small individuals of S-type one survived successfully during this period. The size of small individuals of S-type rotifer collected through fine net became larger in a few hours within larval culture tank. Survival rate of grouper larvae with initial stocking density of 40 thousands in 6-ton concrete tank was 6.3% in 10 days and 0.2% in 53 days after hatching, respectively. Total length of the larvae reached around 29.5 mm in 53days after hatching.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.294-304
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• 2023

Seasonal variations in the community structure of larval fish assemblage in the coastal waters off Gadeok-do were investigated in May, August and November of 2019, and February in 2020. During the study period, a total of 85 larvae species belonging to 45 families were collected. The dominant species were Engraulis japonica, Gobiidae sp., Clupea pallasii, Decapterus maruadsi, and Callionymidae sp.. These five species accounted for 84.1% of the total number of larvae during the survey period. E. japonica, Gobiidae sp., D. maruadsi, and Callionymidae sp. were the dominant species in the summer, while C. pallasii was the dominant species in the winter. The Species Diversity Index was highest in the summer and lower in the fall and winter months, with the lowest values in the spring. As a result of cluster analysis using the number of individual larval fish showed that they are divided into four seasonal groups. In particular, due to seasonal changes in water temperature, an appropriate growth environment was formed in the summer, and an appropriate hatching water temperature for winter spawning fish species was formed in winter, reflecting the seasonal characteristics of the larval fish community.

• Journal of Aquaculture
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• v.7 no.4
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• pp.225-237
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• 1994

Survival and growth rates of flounder larvae fed rotifers and Artemia nauplii enriched by various bio-enrichment techniques were investigated. Enriched materials used in the study were $12\omega-yeast$, 2 commercial emulsified oil and microparticulated products. $\omega-yeast$ were added with one kinds of oils (cuttlefish liver oil, sardine oil, Alaska pollock liver oil, linseed oil) at the level of $5\%,\;15\%\;and\;25\%$. The results are as follows: 1. The growth rate of rotifers cultured with $\omega-yeast$ added $15\%$ cuttlefish liver oil was the best among 12 kinds of $\omega-yeast$ and this performance was almost the same with that of rotifers fed on Chlorella. 2. Survival and growth rates of flounder larvae fed on rotifers and Artemia nauplii enriched with $\omega-yeast$ and the other commercial products were higher than that those of larvae cultured with only Chlorella and non-enriched Artemia. The optimum contents of the cuttlefish liver oil in $\omega-yeast$ for rotifers and Artemia enrichment were $15\%\;and\;25\%$, respectively. 3. Optimum enrichment time and supply amount of $\omega-yeast$ for Artemia nauplii were 6 hr., 1.5 g/g cyst, respectively.

• Journal of Aquaculture
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• v.11 no.4
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• pp.521-528
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• 1998

The influence of starvation on survival, growth and feeding incidence of larval tiger puffer Takifugu rubripes was investigated for 16 days after let them hatched at the temperature of 16.5~18.5${\circ}C$. The effect by delayed initial feeding on larvace was also studied. Almost all larvae began to be fed from the stage of yolk absorption about 5 days after hatching, in which rearing trials revealed that their survival and growth were influenced by food availability. Survival of unfed larvae, which stated to decrease drastically since the oil globule was exhausted about 9 days after hatching, dropped to 50% and 0% respectively on the 11.5th and 16th day. the difference of growth between fed and unfed larvae came into sight on about 5th day after hatching when the initial feeding was started, and had reduced in proportion to the length of starvation period. The condition factors for the unfed larvae were lower than thost of the fed. Of the larvae which had starved less than 5 days, more than 80% could consume food upon feeding. No fish had the ability in having food after 10 days. It appeared that the turning point of recover for the starving larvae came on 7th or 8th day. Their taking-food ability seemed to be affected by the change in swimming activity which depended on the duration of starvation. For the seed production of tiger puffer, therefore, feeding should be initiated as soon as possible, so as to enhance the production and survival of healthy seeds.