To identify sand crab Ovalipes punctatus populations and establish management units for each population, mtDNA COI regions were analyzed. As a result, the clade of O. punctatus in Korea were separated by two with a genetic distance of 0.17 – 2.08%, and there was no significant difference in the result of pairwise FST values representing genetic differentiation by sampling areas (p > 0.05). Also, no geographical separation found in the distribution of haplotypes and the results of the haplotype network. This result suggests that O. punctatus larvae were dispersed for a long time by the ocean current by suffering meroplanktonic period for 1 month, and increased the gene flow due to the development of the swimming legs for the increase in mobility. Therefore, in the results of mtDNA COI region analysis of O. punctatus in the East Sea, Yellow Sea, South Sea and East China Sea (Ieodo) of Korea, no clear intra-species differentiation was found.

The reproduction characteristics of hagfish Eptatretus burgeri were examined using individuals caught in the South Sea of Korea. The spawning season and size at minimum sexual maturity of this species were characterized based on a gonad-somatic index (GSI) and monthly variation egg size (long axis). From monthly variation of GSI, the spawning season was estimated to be from August to September. Developing eggs larger than 10 mm were found in March, and the largest egg size was found in July. The first spawning length was 34.2 cm TL. Batch fecundity ranged from 13 to 117 eggs for hagfish sized from 34.2 cm TL to 77.0 cm TL, respectively, and increased linearly with total length.

매오징어 Watasenia scintillans 유생분포양상을 알아보기 위해 2015년 8, 9, 11월 R/V 탐구 21호로 동해 남서부연안 28개 정점 에 대해 CTD관측 및 IKMT(망목: 500 μm)를 사용하여 저층(최대 수심 100 m)에서 표층까지 경사채집을 실시한 결과, 채집된 매오징어 유생의 개체수는 총 238개체로 외투장(ML) 범위는 0.6 ~ 18.5 였다. 조사기간 중 8월이 9월과 11월보다 유생의 출현정점 수, 출현개체 수, 유생분포밀도에서 현저히 높았다. 특히 8월에 냉수괴가 분포하는 포항 ~평해까지의 동해연안에서 가장 높은 밀도를 보였다. 유생이 채집된 정점의 연직수온분포에서 매오징어의 부화수온(6 ~ 16 )은 주로 40 ~ 180 m의 수심에 위치하였다.

To estimate the movement of Pacific cod Gadus macrocephalus in the Korean Southeast Sea, three type tags were used. A total of 97 Pacific cod were tagged and released with either archival tags or conventional tags. Of these releases, commercial fishermen recovered thirteen conventional tags, and five of seven pop-up tags transmitted data to Argos satellites. Pacific cod began to move towards East Sea after release, and they spent most of their time at depths of 100 to 300m, water temperatures of 0.8 to 14.0°C. However, geographical ranges of their movement limited to area around the southern East Sea. Pacific cod attached conventional tag were recaptured near the release site(Jinhae Bay: main spawning ground) about one or two year after release. Data obtained from tagging investigations suggest that they migrated annually from spawning ground to habtat of the Korean Southeast Sea.