• 한국어류학회지
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• 제22권4호
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• pp.279-284
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• 2010

2010년 9월 남해 상주 앞바다에서 정치망으로 바다뱀과 엽상자어 4개체(TL 109.8~129.7mm)를 채집하였다. 형태적으로 엽상자어는 8개의 소낭이 항문 앞까지 존재하고, 전체 근절수가 141~151개, 전장에 대한 체고가 10% 이하인 점, 흑색소포가 항문 뒤부터 꼬리지느러미 앞까지 8~9개 분포하는 특징에 따라 까치물뱀속(Ophichthus sp.) 어류와 유사한 것으로 확인되었다. 형태적 결과와는 달리 미토콘드리아 DNA 12S rRNA 826 bp의 염기서열을 분석한 결과, 엽상자어는 돛물뱀속(Pisodonophis sp.) 성어와 100% 일치하였고, 돌기바다뱀(Pisodonophis cancrivorus) 성어와는 98.1% 일치하였다. 본 연구결과에서는 형태 동정결과가 분자 동정결과와 일치하지 않는 결과를 보였고, 이는 까치물뱀속과 돛물뱀속 엽상자어기의 형태적 구분이 매우 어렵다는 것을 의미한다. 본 연구에서는 처음으로 한국에서 채집된 돛물뱀속 엽상자어의 형태적 특징을 상세히 기술하였다.

• 한국수산과학회지
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• 제46권5호
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• pp.594-597
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• 2013

Two leptocephali [total length (TL) 68.2-80.5 mm] from the family Ophichthidae, collected from the waters south of Jeju Island, Korea, were identified using morphology. The two ophichthid leptocephali were identified as belonging to the genus Ophichthus based on morphological characters: 131-132 myomeres; nine gut swellings; dorsal fin origin above the middle of the body; five postanal pigments present from the anus to the caudal margin. Ultimately, both leptocephali were identified as Ophichthus asakusae, as the total number of myomeres was consistent with those of adult O. asakusae. Here, we first describe the morphological characteristics of the O. asakusae leptocephalus, and suggest diagnostic characters for leptocephali belonging to the genus Ophichthus.

• 한국수산과학회지
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• 제47권5호
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• pp.597-602
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• 2014

We determined the effects of starvation, water temperature, and water flow on the onset of metamorphosis in leptocephali of the Japanese eel Anguilla japonica. Leptocephali larger than 50 mm (ca. 200 days old) were reared in 10-L tanks under different feeding, water temperature, and water flow regimes. Fasted leptocephali metamorphosed earlier and faster than did the fed ones. Metamorphosis was faster in the high water flow tank (1.2 L/min) than in the tank with flow at 0.6 L/min. The duration of metamorphosis was slightly shorter at $26^{\circ}C$ than at $23^{\circ}C$. To conclude, starvation induced the metamorphosis of artificially produced leptocephali larger than 50 mm TL. Increased water flow and water temperature both appear to induce and shorten metamorphosis.

• 한국어류학회지
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• 제25권2호
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• pp.59-64
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• 2013

한국 제주도에서 채집된 곰치과(Muraenidae) 엽상자어 2개체 (전장 36.2~69.2 mm)를 대상으로 mtDNA 12S rRNA 724 base pair 염기서열을 분석한 결과, 한국 통영에서 채집된 나망곰치(Gymnothorax minor) 성어와 100% 일치하였다. 나망곰치 엽상자어는 전체 근절수가 137~139개, 등지느러미 앞 근절수가 32개, 항문앞 근절수가 82~86개, 전장에 대한 체고가 10% 이상인 형태적 특징을 나타내었다.

• 한국어류학회지
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• 제23권3호
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• pp.217-224
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• 2011

동해에서 바다뱀과 엽상자어 7개체(TL 14.6~68.0mm)를 채집하여, 미토콘드리아 DNA 12S rRNA 861 bp 염기서열로 종을 동정하고, 이들의 개체발생을 기술하고, 진화적 관계를 고찰하였다. 바다뱀과 엽상자어 7개체는 날붕장어 성어와 유전거리(d=0.000)에서 잘 일치하였다. 날붕장어 엽상자어 7개체는 9개의 소낭이 항문 앞까지 존재하고, 전체 근절수가 154~158개, 전장에 대한 체고가 10% 이하이며, 흑색소포가 항문 뒤부터 꼬리지느러미 앞까지 8개 분포하는 형태적 특징을 보였다. 엽상자어의 형태 및 분자 분석결과를 통해 날붕장어는 진화학상 바다뱀아과 및 갯물뱀아과 사이에 위치하는 그룹으로 사료된다.

• Animal cells and systems
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• 제16권5호
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• pp.415-424
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• 2012

Four species of ophichthid leptocephali were identified using 12S rDNA sequences, and their morphological descriptions were first provided based on six individuals (S1-S3,M1, and E1-E2) collected from the East Sea and the Korea Strait between September 2008 and October 2010. Mitochondrial 12S rDNA 859-861 base pairs of ophichthid leptocephali were compared with those of 16 ophichthids adult and 2 outgroups (Anguilla japonica and Conger myriaster). Leptocephali of S1 and E1 were very closely clustered with adult of Scolecenchelys borealis (D=0.002) and Echelus uropterus (D=0.000), respectively. However, leptocephali of S2-S3 andM1 were slightly far clustered with leptocephalus of S1 (D=0.006) and adult of Muraenichthys gymnopterus (0.034), respectively. We believe that S1 and E1 are S. borealis and E. uropterus, respectively, in which the former is unrecorded species in Korea. However, S2-S3 and M1 may be undescribed species belonging to genus Scolecenchelys and Muraenichthys, respectively, because total numbers of myomeres for S2-S3 (148-158) and M1 (151) were not consistent with total numbers of vertebrae or distribution for any adult of Scolecenchelys spp. and Muraenichthys spp. in the world. We propose the new Korean name 'Dong-hae-mul-baem' for S. borealis.

• Ocean Science Journal
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• 제41권4호
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• pp.207-210
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• 2006

Leptocephali of the genus Saurenchelys in the family Nettastomatidae were collected from the coastal area of Pohang, Korea and described as the first record from Korean waters. S. stylura and S. lateromaculatus are characterized by two intestinal swellings, the pattern of pigments in the notochord, and by smaller pectoral fins than those of other genus. They are very similar to each other but they are distinguished by the pattern of pigments in the notochord and the intestinal swellings.

• 한국수산과학회지
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• 제47권6호
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• pp.888-894
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• 2014

Seventeen specimens of leptocephali [9.8-44.5 mm total length (TL)], of the family Ophichthidae, were collected from southeastern waters off Jeju Island and the Korea-Japan intermediate zone, and identified by means of morphology and genetics. These specimens were identified as belonging to the subfamily Ophichthinae based on various combinations of morphological characters: 211-215 total myomeres; 7 gut swellings; 2 liver lobes connected with the gall bladder on the second lobe; 6-7 postanal pigments present from anus to caudal margin. An analysis of the partial 12S rRNA sequences (849 base pairs) of mitochondrial DNA showed that our specimens must be Ophisurus macrorhynchos because their sequences were concordant with those of the adult O. macrorhynchos (genetic distance = 0.000). Furthermore, their total myomeres were consistent with those of the O. macrorhynchos adult. This is the first time that the morphological characteristics of O. macrorhynchos leptocephali have been described for Korean waters, and we suggest diagnostic characteristics for the genus Ophisurus leptocephali. We hypothesize that one of the spawning grounds of O. macrorhynchos is located in the southeastern part of Jeju Island.

• Fisheries and Aquatic Sciences
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• 제18권1호
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• pp.109-113
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• 2015

Three leptocephali (22.2, 22.7, 56.0 mm in total length) collected from the East/Japan Sea were identified by morphological and genetic analyses as belonging to the genus Scolecenchelys (Anguilliformes, Ophichthidae). Morphologically, the specimens were characterized by 148-158 myomeres, 10 gut swellings, dorsal fin origin above middle of the body, and 6 postanal melanophores between the anus and the caudal margin. An analysis of an 849-base pair 12S rRNA sequence of mitochondrial DNA showed that sequences are concordant with those of adult Scolecenchelys fuscogularis (genetic distance = 0.001). Furthermore total number of myomeres is consistent with the total number of vertebrae in adult S. fuscogularis. This study provides the first description of the morphological characteristics of S. fuscogularis leptocephali and their variations with size. The Korean name of S. fuscogularis is "Ga-neun-mul-baem", established by Ji et al. (2012).

• 수산해양기술연구
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• 제51권4호
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• pp.527-534
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• 2015

The twenty six specimens of leptocephali (15.8-32.6 mm TL) of the family Congridae, collected from southeastern waters offshore of Jeju Island during August 2014, and were identified by means of morphology and genetics. Those specimens were identified as belonging to the family Congridae based on various combinations of morphological characters. An analysis of the partial 12S rRNA sequences (886 base pairs) of mitochondrial DNA showed that our specimens must be Gnathophis nystromi, because their sequences were concordant with those of G. nystromi adult (genetic distance= 0.001), furthermore their total myomeres being consistent with those of G. nystromi adult. Catch rates of G. nystromi leptocephali were higher in the offshore regions than coastal regions of Jeju Island. The smallest leptocephali (< 20 mm TL) were collected offshore from Jeju Island. We hypothesize that one of the spawning grounds of G. nystromi is located offshore in the Jeju Island. In conclusion, the hatched preleptocephali of G. nystromi might have been transported from offshore near Jeju Island to the Korea Strait by the Kuroshio Current and Tsushima Warm Current.