Four species of ophichthid leptocephali were identified using 12S rDNA sequences, and their morphological descriptions were first provided based on six individuals (S1ÁS3, M1, and E1ÁE2) collected from the East Sea and the Korea Strait between September 2008 and October 2010. Mitochondrial 12S rDNA 859Á861 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 00.002) and Echelus uropterus (D 00.000), respectively. However, leptocephali of S2ÁS3 and M1 were slightly far clustered with leptocephalus of S1 (D 00.006) 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, S2ÁS3 and M1 may be undescribed species belonging to genus Scolecenchelys and Muraenichthys, respectively, because total numbers of myomeres for S2ÁS3 (148Á158) 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.

The stomach contents of Lumpenella longirostris, Malacocottus gibber and Bothrocara hollandi from the East Sea were examined to determine their feeding ecology. Specimens were caught seasonally from 2004 to 2006. The primary prey items of each species included crustaceans and mollusks. L. longirostris is a benthophage that primarily consumes bottom crustaceans and bivalves. M. gibber and B. hollandi are meso-pelagicphages that primarily consume amphipods and cephalopods. However, the species are opportunistic feeders that exploit the available prey in their habitat. The empty stomach ratio of the species is larger than that of offshore species (e.g. hairtail fish and yellow goose fish), and the prey diversity of the species evaluated in this study was much smaller than that of offshore species.

The dominant species were Thamnaconus modestus and Sebastes schlegeli. Hierarchical clustering analysis showed five fish groups, with frequency and number of individuals similar to results of correspondence analysis (CA), which showed a closer relationship to the year term than the season term. CA showed that temperature was an important factor influencing fish species richness and abundance. Three main fish assemblage types coexisted around Dokdo: an East Sea coastal fish assemblage, a subtropical fish assemblage, and a cold water fish assemblage.

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