• 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.

• 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.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1209-1216
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• 2014

This feeding experiment was conducted to investigate the effects of slurry type diet on growth performance and survival rate of growing leptocephalus, eel larva. We need to find new materials of diets for rearing eel larvae. Test diets were formulated with the eggs of the shark, fish soluble concentrate, soybean peptide and fish protein hydrolysate. Fish (average length 6 mm) were fed 3 slurry type diet(A, B and C) based on shark egg for 5 times per day. During feeding experiment, survival rates were significantly different among 3 slurry type diets. Total protein, lipid, moisture, ash and free amino acids contents were analyzed for slurry type diets. Leptocephalus fed the C slurry type diet was grown up to $38.0{\pm}9mm$ at 150 days. But all leptocephalus fed B slurry type diet were died at 100 days, reaching $16.4{\pm}8mm$. This results suggest that basic information for diet development of eel leptocephalus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.568-573
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• 2021

A single leptocephalus specimen of Albula glossodonta belonging to the family Albulidae under the order Albuliformes, was collected from the southern sea of Korea in May 21, 2019. This species is distinguished from A. vulpes in the number of melanophores at the base of the caudal fin. In addition, our specimen was readily distinguished from A. argentea in having no melanophores on the operculum, at the base of the dorsal fin and in front of the pectoral fin. Also it was well distinguished from A. gilberti in having no melanophores on the operculum, in front of the pectoral fin and on the lateral body. A molecular analysis based on 467 bp sequences of the mitochondrial DNA 16S rRNA shows that the leptocephalus is well matched to A. glossodonta adult (K2P distance=0.002). We report the first occurrence of A. glossodonta leptocephalus in the Korean waters, and propose it's new Korean name, "Nam-bang-yeoeul-myeol".

• Korean Journal of Ichthyology
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• v.17 no.3
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• pp.217-220
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• 2005

Three specimens of leptocephalus larvae (33.4~35.2 mm in SL) were collected from the southern coast of Jeju Island, Korea, by an aquatic lamp on August 14, 2004. These larvae were identified as Elops hawaiensis because of their having a forked caudal fin, a smaller anal fin than dorsal fin, and anal-fin position posterior to dorsal fin.

• Ocean and Polar Research
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• v.27 no.4
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• pp.491-495
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• 2005

The morphology of a leptocephalus Nettenchelys gephyra (Hettastornatidae) is described from one specimen collected of Pohang $(35^{\circ}46'N,\;129^{\circ}52'E)$ in the East Sea, Korea on December 2003. The body is laterally compressed. The body deepens gradually behind the head to the deepest point of the midbody range that is 15.8% of the standard length 31.7mm, then tapers gradually toward the tail. The anus is located somewhat posteriorly to midbody. There are two intestinal swellings, which are located at the 19th and 41st myomere, respectively. The vertical blood vessel's last location is at the 48th myomere. The lateral pigment spot begins at the 84th myomere.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.589-593
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• 2013

Scolecenchelys borealis was first added to the Korean fish fauna based on one leptocephalus specimen (total length (TL) 59.2 mm) collected from Dokdo, in the East Sea. Recently, however, Scolecenchelys borealis has been treated as a junior synonym of Scolecenchelys aoki, necessitating review of the scientific name S. borealis. This study describes the morphological characteristics of S. aoki based on an adult specimen (TL 230.0 mm) collected from the sea south of Korea and compares its mitochondrial DNA 12S rRNA sequence with that of the S. borealis leptocephalus. The adult S. aoki is characterized by several morphological features: vertebral formula 59-55-135; preanal lateral pores 55; infraorbital pores two; teeth on upper jaw visible externally when the mouth is closed; the dorsal fin originates just behind the anus; both jaws and vomerine teeth are conical, arranged in two rows. An analysis of an 886-base paire sequence of the 12S rRNA showed that adult S. aoki was concordant with the S. borealis leptocephalus (sensu Ji et al., 2012), indicating that both are the same species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.551-556
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• 2020

Eel Anguilla japonica is an economically important inland culture fish species in East Asian countries, particularly in Korea, Japan, China, and Taiwan. In this study, the effects of feeding frequency on larval growth and survival rate were investigated. Eel larvae (average length, 6 mm) were fed a slurry-type diet containing shark eggs three, five, seven, or nine times per day. Survival rates differed significantly among the four experimental groups. Feeding frequencies of at least five and seven times a day were required until 15 and 30 days after hatching, respectively, to maintain an acceptable survival rate. Leptocephalus growth improved with increased feeding frequency until 15 days after hatching. The results suggest that providing an opportunity for early food intake enhances eel survival and growth in the early leptocephalus stage.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.05a
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• pp.575-575
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• 2002

• Journal of Marine Life Science
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• v.8 no.2
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• pp.128-135
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• 2023

The present study was tried to identify whether the eel's larva was close to a conger (Conger myriaster), a pipe conger (Muraenesox cinereus) or four species of Anguilla. Experimental fishes were collected by set net in the gulf of enggang, Namhae, Korea from May to June. Their morphological characteristics were compared with adult fishes of a conger, a pipe conger and four species of Anguilla. For genetic classification, DNA was isolated and amplified by using 12S rRNA and 16S rRNA primer set. The PCR products were direct sequencing in both directions. The nucleotide sequences were analyzed using softwares. As results of morphological measurement on eel's larva, the percentages of head length and preanal length against total length were similar with a conger. Based on the nucleotide sequences, the phylogenetic tree also revealed a close relationship to a conger. Therefore, eel's larva, caught in Namhae from May to June, was identified into a conger's larva.