• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.2
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• pp.134-148
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• 2021

During the ichthyoplankton survey around the Chilsan Island (previously known as the biggest spawning ground of the Sciaenidae) in the southwestern sea of Korea from April to June in 2019 using ring nets, we collected a total of 12 individuals belonging to the family Sciaenidae. Using molecular methods, we identified five sciaenid species (Collichthys lucidus, Collichthys niveatus, Johnius grypotus, Nibea albiflora, and Pennahia argentata), and described and compared them on the basis of the preflexion larval stage. C. lucidus was well distinguished by the presence of occipital crests at preflexion stage. Although there were no occipital crests, preflexion larva of C. niveatus was distinguished by the absence of melanophore except for the upper part of the abdominal cavity. J. grypotus and N. albiflora were very similar morphologically, but were distinguished by myomere height (15.22-15.53% in J. grypotus vs. 11.66-12.78% in N. albiflora) in the percentage of notochord length, and eye diameter (32.58-33.37% in J. grypotus vs. 40.32-42.53% in N. albiflora) in the percentage of head length between specimens of similar size (J. grypotus: 3.22-3.23 mm, N. albiflora: 3.04-3.13 mm). P. argentata were distinguished by distribution of ventral caudal melanophore (one row of small spot in P. argentata vs. irregular patches on the central part of caudal in J. grypotus and N. albiflora). Comparative morphological studies using more diverse species must be conducted for more comprehensive understanding of the morphogenesis of Sciaenidae.

• Fisheries and Aquatic Sciences
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• v.27 no.5
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• pp.294-305
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• 2024

Tomini Bay in Gorontalo offers significant potential for amphidromous goby-fry, a group of fish found in at least five estuaries in the area, namely Bone-Bolango, Paguyaman, Bilungala, Tombulilato, and Taludaa Estuaries. Preliminary results were limited to only two locations in estuarine waters, namely the Bone-Bolango and Paguyaman rivers. Further exploration of goby-fry species in various locations within Tomini Bay is essential to enhance knowledge about the abundance and aid conservation efforts. Therefore, this study identified the goby-fry species and created their distribution map in the waters of Tomini Bay Gorontalo. The samples used were obtained from daily catches of fishermen in the five estuaries during the recruitment period from February to September 2022. These samples were categorized based on their morphological similarities and specific melanophore patterns. Distinct groups with different melanophore patterns from those previously reported were identified as newly recorded species, photographed, and described in terms of their morphology. Furthermore, two specimens from each newly recorded species underwent molecular identification using the cytochrome oxidase subunit 1 (COI) gene for DNA amplification and were analyzed through the Basic Local Alignment Search Tool (BLAST) method. The phylogenetic tree was constructed using the Maximum Likelihood Method. The results showed the existence of nongoby-fry species caught together with goby fry school. A total of 75,881 goby-fry and 1,687 nongoby-fry were successfully collected. Among the goby-fry species, 13 were identified, including three new records, namely Eleotris fusca (Forster, 1801), Sicyopterus microcephalus (Bleeker, 1855), and Sicyopus zosterophorus (Bleeker, 1856). This study also documented the existence of nongoby-fry species, namely Anguilla celebesensis (Kaup, 1856), Moringua microchir (Bleeker, 1853), and Microphis leiaspis (Bleeker, 1854). It significantly contributed to the understanding of fish biodiversity in Tomini Bay.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.120-128
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• 2024

In this study, the characteristics of the early life history were investigated for the Hypomesus nipponensis in the west coast Daeho Bay. Egg's were adhesive eggs that had the property of sinking in water in a circular shape. The size of mature eggs was 0.52~0.66 (average of 0.59±0.03, n=30) mm. The hatching time took 140 hours at a water temperature of 22~23℃. Immediately after hatching, the yolk sac larvae was 4.78~5.60 (average of 5.25±0.26, n=30) mm in total length, and the mouth and anus were not completely opened. On the 7 days after hatching, the preflexion larvae was 5.91~6.64 (6.32±0.21) mm in total length, and the mouth and anus were opened, and feeding activities were started. On the 25 days after hatching, the flexion larvae was 9.70~12.3 (10.2±0.63) mm in total length, and the end of the spine at the tail end began to bend upward. On the 42 days after hatching, the postflexion larvae was 14.1~18.8 (16.9±1.44) mm in total length, and the end of the spine at the tail was completely bent at 45°. On the 56 days after hatching, it reached the integer with 10 dorsal fins, 16 anal fins, 7 ventral fins, and 19 caudal fins. According to the study, there were spot-shaped melanophore vesicles under the pectoral fins during the incubation period, the different positions of the egg yolk compared to the battlefield, the deposition of melanophore vesicles on the back and under the body of the caudal part during the postflexion larvae period, and the absence of melanophore vesicles on the torso between the head and the starting point of the dorsal fin. It was distinguished from related species in that melanophore vesicles were deposited in one row from the back of the body to the caudal part during the juvenile period.

• Ocean Science Journal
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• v.43 no.2
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• pp.101-106
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• 2008

A single specimen of Albula leptocephalus (55.7 mm SL) was collected from the southern coastal waters of Korea using an aquatic lamp. It is characterized by having a ribbon-like body with a small head and a well-forked caudal fin. Although the general appearance was similar to the leptocephalus of A. vulpes including myomere counts and fin ray counts, the melanophore deposition was different from that of A. vulpes. This leptocephalus specimen was confirmed with A. forsteri using the cytochrome b mtDNA (Cytb) analysis. The genetic distance of Cytb between the present leptocephalus and A. forsteri is 0.006-0.038, which falls into the cutoff point separating Albula species into eight deep lineages including the four valid species. Its genetic characteristic have more similarities to those of Fiji than those of Hawaii and the Northern territory of Australia.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.5
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• pp.442-448
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• 2003

Melanin concentrating hormone (MCH) regulating color change of fish skin was identified from brain cDNA library of Olive flounder (Paralichthys olivaceus) during the analysis of Expressed Sequence Tags (ESTs). Olive flounder MCH gene consisted of 598 nucleotides encoding 150 amino acids. Olive flounder MCH protein revealed to contain signal peptide of 19 amino acid residues, pro-MCH of 131 amino acids being processed to biologically active and mature form of hormone with 25 amino acid residues at the carboxyl terminus. A comparative structural analysis revealed that Olive flounder MCH precursor had low sequence identity with other fish species and mammalian counterparts, while the amino acid sequences of mature hormone had a relatively high identity and more conserved. RT-PCR analysis revealed that olive flounder MCH precersor gene was expressed spectically only in the brain and not in other tissues.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.507-512
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• 2012

One leptocephalus (TL 59.9 mm) from the family Ophichthidae collected from Jeju Island, Korea, was identified using morphological and molecular methods. Our ophichthid leptocephalus was identified as belonging to the genus Muraenichthys based on morphological characters: 157 myomeres; the origin of the dorsal fin located a little in front of the anus; a distinct melanophore present on the opercle; and six gut swellings present. An analysis of 886 base pairs of the 12S rRNA mtDNA sequences showed that our leptocephalus must be Muraenichthys gymnopterus, because its sequences were concordant with those of an adult M. gymnopterus (d=0.001) and next to those of Muraenichthys sp. leptocephalus (d=0.034). Here, we are the first to describe the morphological characteristics of the M. gymnopterus leptocephalus.

• 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 Ichthyology
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• v.1 no.1_2
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• pp.1-8
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• 1989

In August, 1988, matured adults of devil stinger were collected from Jinhae Bay and Jaran Bay, Kyongsangnam-do, Korea and kept in the aquarium (1 ton) for spawning. The egg development was observed with the eggs laid in the aquarium of adult fish. The diameters of eggs ranged from 1.2 to 1.3 mm (n=6), and no oil globules were found in the eggs. The hatching took place from 26 to 29 hours after eight cells stage at the water temperature of $24.9-26.5^{\circ}C$. The newly hatched larvae were 2.47~3.10 mm in total length with xanthophore on the body and yolk sac. Myomere number was 13+16-17=29-30. Two days after hatching, larvae were 3.61-4.16 mm in total length, and 3 to 4 large spots of melanophore appeared on the large pectoral fin. Three days after hatching, larvae were 3.97-4.29 mm in total length, and the larvae absorved the yolk material completely to become post larvae with 4-5 rays of the pectoral fin. Six days after hatching, larvae attained 4.07-5.46 mm in total length, and 11 rays and 8-9 spots of melanophore were developed on the pectoral fin.

• The Korean Journal of Zoology
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• v.28 no.3
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• pp.137-150
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• 1985

The dorsal skin of Rana temporaria dybowskii Guenther was examined under electron microscope. The results of the fine structures in the xanthophores, iridophores and melanophores were as follows: Xanthophores: Xanthophores were filled with pterinosomes and carotenoid vesicles. Type I pterinosomes had a clear limiting membrane. Type II pterinosomes had the inner fibrous structures. Tyep III pterinosomes were characterized by a few superficial lamellae and type IV pterinosomes by multiple concentric lamellae. Especially typical type II and type III pterinosomes were evenly distributed in the cytoplasm. Iridophores: Iridophores were situated between a xanthophore and a melanophore in the outer part of the dermis just below the basement membrane. Iridophores were filled with reflective platelets, each of which is rectangular and convex lens-like in shape. These platelets were closely contiguous and leave no interspace between them. Endoplasmic reticulum and a few mitochondria were observed in the supranuclear cytoplasm. Melanophores: Dermal melanophores contained numerous melanosomes. The dendritic precesses of the melanophore containing the melanin granules extented up the lateral sides of the iridophore. Epidermal melanophores were filled with melanin granules which appered as the same electron density. A few melanin granules were observed in a cornified surface cell.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.253-262
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• 2023

This study compared the results of observing the early life history of Gymnogobius urotaenia, which lives in Hwangbocheon Stream, an inflow stream on the east coast, with the differences between fish of the same Gobiidae fishes. In May 2022 and 2023, fertilized eggs and brood stork scattered under rocks were captured twice in Hwangbocheon Stream. The spawning amount was 827~1,540 and the orchid was a elliptical in shape with a size of 3.21×1.07 mm. The stage of ovulation observed in the laboratory was 16 cells, and hatching began after 193 hours. The breeding water temperature range was 18.8~19.3℃. Newly after hatching larvae, the yolk sac with a total length of 3.84~4.33 (average 4.10±0.17, n=30) mm, and the anus was not open. 6 days after hatching of incubation, the total length was 5.32~6.11 (average 5.67±0.25, n=30) mm, absorbing all egg yolk and transitioning to the preflexion larvae, ingesting food, and developing a keynote on the tail fin. 15 days after hatching, the end of the urostyle end was completely bent at 45° with a total length of 7.33~8.52 (average 7.81±0.46, n=30) mm and transitioned to postflexion larvae, and melanophore developed throughout the body. 38 days after hatching, the total length is 22.1~26.1 (23.8±1.36, n=30) mm and the number of fins (6 first dorsal fins, 11 second dorsal fins, and 11 anal fins, 12 ventral fins) is all the number of fin base became integer and transferred to the juvenile. As a result of the study, it was possible to distinguish the melanophore of postflexion larvae of G. urotaenia from other postflexion larvae Gobiidae fish in that they were distributed throughout the body of half the body and tail.