• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.1
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• pp.29-38
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• 2005

The distributions of fish larvae and juveniles from the East China Sea, Yellow Sea and near Tsushima Island were investigated in Spring using the Maruchi (1994-1995) and Unagi (1996-1997) nets. A total of 94 species of fish larvae and juveniles belonging to 49 families under 17 orders were identified, of which Engraulis japonicus was dominant in every year except 1995 where Trachurus japonicus was dominant. Cluster analysis based on abundance and species composition by sampling stations (St.) revealed that the similar stations formed an arcuate group from Tsushima Island to southern Jeju Island in 1994, and from the Yellow Sea to southern Jeju Island in 1996. We concluded that these patterns resulted from the influence of the Tsushima Current prevailing in the east, and the Chinese Continental Waters and/or Hwanghae Cold Waters prevailing in the west, with Jeju Island exerting an influence in the centre. The diversity and composition of St. 97-3 and St. 97-5, both located where the Tsushima Current splits from the Kuroshio Current, was greatly different despite their close proximity. However, the former is located on the continental shelf, with the latter on the continental slope. This suggested that both topography and the Kuroshio Current have the most influence on the distribution of fish larvae and juveniles in this region. Furthermore, the weak Hwanghae Cold Waters of 1997 may have also limited the mixing of fish larvae and juveniles between the two stations.

• Parasites, Hosts and Diseases
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• v.21 no.1
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• pp.6-10
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• 1983

A study of infestation patterns for larval trematodes from fresh-water fish and brackish-water fish was carried out during the period from June to October in 1982. They were collected by netting, asking with rod and lino, and using the a bait of crushed oil cake in a transparent plastic bowls at the three localities, Daebon-dong, Kugil-dong, and Hoam-dong in the river Taechong, Kyungpook Province, Korea. Five species of fresh-water fish, the crussian carp, Carassius carassius Linnaeus, the bullhead, Coreobagrus brfvicorpus Mori, the fat minnow, Morose oxycephalus (Bleeker) , the flat bitterling, Paracheilognathus rhombea (Temminck et Schlegel) , and the catfish, Parasilurus asotus (Linnaeus), and two kinds of brackish-water fish, the grey mullet, Mugil cephalus(Linnaeus) and the sweet-fish, Plecoglossus aztivelis (Temminck et Schlegel) were examined. Four species of the metacercariae, Exorchis eviformis, Metacercaria hasegawai, Metorchis orientalis and undetermined larvae were found. Of these, the encysted larvae of the human intestinal fluke, Metagonimus yokegawai, were found from three kinds of fresh-water fish, the crussian carp, the bullhead and the fat minnow and one species of brackish-water fish, the sweets;sh and the infestation rates for the larvae varied appreciably from fish to fish. The intensity of infestation with the Metagonimus larvae in the three species of fresh-water fish was low, and the average number of the larvae per gram of flesh varied from 0.5 to 0.2. By comparison, the brackish-water fish wqs more heavily infested and the mean number of cysts per gram of flesh in Plecoglossus altivelis was 109.2. It was foung that infection with Metagonimus yokogawai os caused by consuming raw fresh-sater fish and brackish-water fish caught in the river Taechong, Kyungpook Province, Korea.

• Ocean and Polar Research
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• v.24 no.4
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• pp.443-448
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• 2002

A study on the ichthyoplankton assemblage was conducted around Dokdo in the East Sea in September 1999 and May 2000. Sixteen species of fish larvae including eggs were collected during the surveys. Anchovy (Engraulis japonicus) eggs and larvae were comprised of 2.0% and 94.5% of total samples in number, respectively. Muller's pearlside (Maurolicus muelleri) eggs and larvae were comprised of 95.0% and 3.2%, respectively. The other species mostly composed of warm water species were less than 2% of total samples in number. The number of species and abundance of the fish lawae and eggs were higher in September than in May. Although there were limited data on the ichthyoplankton around Dokdo in summer and winter, this study area seems to be used for the spawning or nursery ground of fishes.

• Journal of agricultural medicine and community health
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• v.13 no.1
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• pp.32-40
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• 1988

Anisakiasis occur after the ingestion of raw marine fish and squid containg anisakid larvae. In recent years about 40 cases of anisakiasis have been recorded in Korea. Considering, however, the Korean style of eating raw fish, many more cases would exist and prevention is necessary. We describe the infection rate of anisakid larvae in 13 species of marine fish and squid which were caught in the Korean sea. And each extracted larva is classified according to morphological characters. The results are following ; Scomber japonicus, Pseudosciaena manchurica, Trichiurus haumela showed high infection rate of anisakid larvae. Although Sepia esculenta showed low infection rate, most of anisakid larvae found in Sepia edulis are embedded in muscles. So relative high frequent rate of anisakiasis may developed by Sepia esculenta. Five type (Anisakis Type I, Terranova Type B, Raphidascaris sp., Contracaecum Type A, Contracaecum Type D) of anisakid larvae are classified according to their morphological characters.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.1
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• pp.23-29
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• 2022

This study was carried out to clarify the egg, larvae and juveniles development of Misgurnus anguillicaudatus, and relationships of M. anguillicaudatus and M. mizolepis, Cobitididae Fishes. The adult fishes were collected in Samsan-cheon, Haenam-gun, Jeollanam-do, Korea and their spawning inducement was carried by ovaprim injections. The egg shape was circular and the size was average 1.12 mm. The eggs were hatched at 61 to 72 h after fertilization. The newly hatched larvae had an average 3.23 mm in total length (TL). At 5 days after hatching, the larvae reached to post larval stage and they were 10.3 mm in TL. At 19 days after hatching, it reached to juvenile stage and was 25.3 mm in TL. The egg size of M. anguillicaudatus was almost same as M. mizolepis but the hatching period of M. anguillicaudatus has taken longer. It was possible for interspecific distinguishability of M. anguillicaudatus and M. mizolepis when their larvae reached to juvenile stage by the development of keel-like ridges.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.2
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• pp.71-79
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• 1998

Fish larvae and environmental variables were collected in the sea around Cheju Island of Korea in November, 1986. Fish larvae were found at the 43 of 44 stations. Abundance of fish larvae rangεd from 3 to 259 indiv./$10^3\;m^3$ (average 50 indiv./$10^3\;m^3$) Dominant species were Engraulis japonicus, Champsodon snyderi, Gobiidae, Sebastiscus marmoratus, and Synagrops philippinensis, which comprised 56.6% of total fish larvae abundance. 43 stations were c1assified into two groups by c1uster analysis based on the abundance of fish taxa. Most stations of Group I were located in the middle reach of Tsushima Current and had higher number of species and abundance than the sites of Group II which cover the marginal areas of Tsushima Current, Korean Coastal Waters, and coastal water of China. The dominant taxa in the sites of the Group I were E. japonicus, Gobiidae, S. philippinensis, Aulops japonicus, Bregmaceros spp., Benthosema pterotum, Lampanctus spp., etc., all of which are typical warm-water species. Therefore, Tsushima Current seems to be the most critical factor regulating the structure of fish larvae community in the study area. The discriminant analysis using the environmenta1 variables (temperature, salinity, and dissolved oxygen) produced result with a difference only of 11.6% from that of c1uster analysis using the taxa composition and abundance data. Consequently, the structural type of fish larvae community can be used for predicting the changes of environmental conditions in the study area.

• Development and Reproduction
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• v.21 no.4
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• pp.399-406
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• 2017

This study was conducted to investigate egg development and larvae morphological development of catfish and to provide basic data to clarify the genetic relationship with Siluriformes fish. The mother fish that was used in this study was caught in the stream of Nakdong River in Uiseong-gun, Gyeongbuk. The temperature range of the breeding was $23.0-25.0^{\circ}C$ (mean $24.0{\pm}1.0^{\circ}C$) and egg size was 1.62-1.70 mm (mean $1.66{\pm}0.05$, n=30). Eggs of catfish began hatching at 54 hours and 40 minutes after fertilization. Immediately after hatching, the total length of larvae was 3.60-3.65 mm (mean $3.62{\pm}0.03$, n=5) and had an egg yolk without swimming ability. On the third day after hatching, the larvae at the medium stage was 8.00-8.65 mm (mean $8.32{\pm}0.45$) in total length, and two pairs of whiskers formed around the mouth were elongated. On the 12th day after hatching, the larvae at the juvenile stage was 16.5-17.0 mm (mean $16.7{\pm}0.35$) in total length, and the stem of each fin was in the range, and the juvenile at this period was morphologically similar to the mother fish.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.3
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• pp.243-251
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• 2019

The ichthyoplanktons were sampled by Bongo net to study the distribution of the eggs and larvae in the West coastal waters of Korea during the study period (February, May, August and October of 2017). Collected fish eggs were divided into Engraulis japonicus and unidentified species. The most dominant species, Engraulis japonicus accounted for 79.52% of the total fish egg, which was followed by unidentified species (20.48%). The total of 36 taxa in fish larvae were identified based on morphological and molecular characteristics. Fish larvae were dominant by Gobiidae species. 48.30% of the total catch in abundance, which was followed by Engraulis japonicus (31.86%). These two taxa composed 80.16% of the total collected fish larvae. The seasonal diversity index of species from the collected fish larvae in the West coastal waters in 2017 was 0.625-1.883 and the evenness index was 0.380-0.865. In addition, dominance index was 0.618-0.920 and richness was 0.573-3.189.

• Journal of fish pathology
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• v.23 no.3
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• pp.421-427
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• 2010

Anisakid nematodes third stage larvae were isolated from the muscles of masou salmon (Oncorhynchus masou). Fish were purchased from Jumunjin fishery market in Gangneung. Four Anisakid third stage larvae were isolated from 4 fish. Molecular identification of the isolated worms was conducted by PCR-RFLP analysis of ribosomal DNA internal transcribed spacer region and direct sequencing of mitochondrial DNA cox2 gene. As results, all the tested individual worms were identified as Anisakis simplex (sensu stricto). This is the first report of molecular detection of anisakid worms in salmonid fishes in Korea.

• Development and Reproduction
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• v.19 no.4
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• pp.189-196
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• 2015

This study was examined the ovogenesis of Ussurian bullhead, Leiocassis ussuriensis and the morphological development of its larvae and juveniles and to use the results as basic information for the preservation of species and resource enhancement. For artificial egg collection, human chorionic gonadotropin (HCG) was injected at a rate of 10 IU per gram of fish weight. During breeding period, water temperature maintained at $24.5{\sim}26.5^{\circ}C$ (mean $25.0{\pm}0.05^{\circ}C$). The process of ovogenesis reached the two-cell stage in 50 minutes after fertilization. In 73 hours of fertilization the movement of the embryoid body became active state and the larvae began to hatch from the tail through the oolemma. Length of prelarvae were 6.33~6.50 mm long (mean $6.40{\pm}0.06mm$) just after hatching having yolk with their mouth not opened. After thirty eight days of hatching, juveniles were 30.6~32.5 mm long (mean $31.5{\pm}0.65mm$). The color was dark yellowish brown throughout the entire body, and the number of caudal fin rays developed to thirty six perfectly.