The subgenus Tricoma Cobb, 1894 comprises free-living marine nematodes encompassing a total of 83 validated taxa. Within this diversity, twenty-one taxa thrive in the deep sea, while twenty-three are found in coral reefs, flat areas, or green algae. Additionally, eleven taxa inhabit the sublittoral zone at depths exceeding 10 meters, and the remaining taxa are situated on beaches, coasts, or in habitats lacking detailed information. In the course of a survey focused on the East Sea free-living marine nematodes, we identified four new and two previously unrecorded species belonging to the subgenus Tricoma. Specifically, two new species, Tricoma (Tricoma) breviseta sp. nov. and T. (T.) donghaensis sp. nov., were discovered in mud-sandy sediment in deepsea environments below 2000 meters within the Ulleung Basin and Hupo Bank. Two previously unrecorded species [T. (T.) paralucida Decraemer, 1987 and T. (T.) similis Cobb, 1912] and the two newly found species [T. (T.) longicauda sp. nov. and T. (T.) ulleungensis sp. nov.] were obtained from subtidal coarse sand at a depth of 20 meters during a survey of the waters surrounding Ulleungdo Island. The distribution and information on validated taxa within the subgenus Tricoma were systematically collected, reviewed, and cataloged. Detailed morphological features and illustrations of Tricoma species from Korea were provided through the use of differential interference contrast microscopy.

Henricia specimens were collected using a dual approach of trimix scuba diving and fishing nets. This inclusive collection encompasses the discovery of two species highlighted in this study and introduces and provides comprehensive descriptions for Henricia kinkasana and Henricia longispina aleutica. The descriptions offered in this study were derived from the thorough examinations of external morphological characteristics. The documentation provides detailed insight into key traits related to the abactinal and actinal skeletons and spines of these newly recorded species in Korea. This comprehensive examination contributes to our understanding of the distinct morphological characteristics defining each species within the genus Henricia.

Two newly recorded sea stars, Henricia densispina (Sladen, 1879) and H. reniossa asiatica Djakonov, 1958, collected from the East Sea of Korea using fishing nets, were described in this study. Morphologically, H. densispina is characterized by the shape (sub-triangular) similarity of the intermarginal plates to the superomarginal plates. Henricia reniossa asiatica Djakonov, 1958, has long and slender arms (R/r=7.2- 9.1); clustered abactinal paxillae with 3-13 abactinal spinelets; a denuded abactinal skeleton made up of crescentic, elongated cross-shaped, the presence of small ossicles that divided the papular areas; and an adambulacral armature comprised of 14-17 spinelets. This study provides the first occurrence of H. densispina and H. reniossa asiatica in the Korean fauna and a detailed morphological description of these species’ key characteristics is provided.

The distributions of common minke whales observed in the East Sea in ten surveys in May of 2003, 2005, 2006, 2007, 2009, 2010, 2012, 2015, 2016 and 2020 were investigated using satellite sea surface temperature (SST) derived from the Moderate Resolution Imaging Spectrometer (MODIS). Most of the minke whales were observed in the waters off the Korean Peninsula at 36-38.5° N, which is expected as the highly productive coastal upwelling area. Yet, no minke whale was observed in 2006 when a relatively larger scale coastal upwelling occurred with SST at 11°C. In 2016 and 2020, the warm water higher than 17°C extended widely in the area, and the minke whales were observed in the offshore waters, deeper than 1,000 m. 87.5% of minke whales observed in May appeared in the SST from 13 to 16°C, and they seemed to avoid relatively high temperatures. This suggests that optimum habitat water temperature of minke whales in May is 13-16°C. The SST in the area had risen 1.67°C from 2003 to 2021, and it was remarkably higher than in other parts of the surrounding areas. The future temperature rising may change the route and timing of the migration of minke whales in the study area.

Benthic harpacticoids were collected from the East Sea of Korea. Specimen were identified as members of the genus Robertgurneya Apostolov & Marinov, 1988 based on the following characteristics: the fourth segment of antennule with aesthetasc, antenna with three-segmented exopod, shape of mandible, and P1-P4 armature formula. Robertgurneya donghaensis sp. nov. is morphologically most closely related to R. simulans (Norman & Scott T., 1905) and R. similis similis (Scott A., 1896). However, R. donghaensis is characterized by the rostrum with a pointed tip, caudal rami about as board as the length of its inner edge, the first segment of the P1 endopod much longer than entire exopod, and the P5 exopod with five setae in male. The genus Robertgurneya is reported from Korean waters for the first time.

A new free-living marine nematode species of the genus Pseudosteineria Wieser, 1956 affiliated with the family Xyalidae is described based on specimens collected from the sediment of a subtidal benthic environmental habitat in the East Sea, Korea. Pseudosteineria varisetis sp. nov differed from its congeners by the combination of the following characteristics: a relatively long body (1,628-1,691 μm long in males), a circular amphideal fovea situated behind the subcephalic setae, the presence of lateral cuticular alae starting from behind the nerve ring, the presence of eight groups of long subcephalic setae, the presence of irregularly distributed variable lengths of somatic setae on the body, solid spicules (43.2-43.9 μm long) with a cephalated proximal end, a long tubular shaped gubernaculum with dorsal swelling, and a conico-cylindrical tail with two to four terminal setae. In this report, we provide a taxonomic description and illustrations of a new species of the genus Pseudosteineria by differential interference contrast microscopy.

A new free-living marine nematode species of the genus Belbolla Andrássy, 1973 belonging to the family Enchelidiidae is described based on specimens collected from the sediment of a subtidal benthic environmental habitat in the East Sea, Korea. Belbolla wonkimi sp. nov. differs from its congeners by the combination of the following characteristics: a relatively long body (3263-3396 μm), the absence of ocelli, nine oesophageal bulbs in the posterior pharynx, well-developed two winged precloacal supplements, longer spicule length (115-130 μm, 1.6-1.8 anal body diameter long), and a triangle-shaped shorter gubernacular apophysis (17-18 μm). Comparative tables on the biogeographical and morphological characteristics of Belbolla species are presented. A DIC (differential interference contrast) photomicrograph of the new species is also provided. This is the first taxonomic report on the genus Belbolla from Korean waters.

Sea stars were collected from the adjacent waters of Jukbyeon and Jumunjin, Korea, using fishing nets at depths of 70-100 m. The specimens were identified as Henricia perforata (O.F. Müller, 1776) in the family Echinasteridae and order Spinulosida, with worldwide species distribution. H. perforata can be distinguished from some morphologically related Henricia species by its long, slender, and pointed adambulacral spines. The abactinal skeleton of H. perforata has wide papular areas resembling those of H. pachyderma, but the former has more papulae (two to seven). Previously, two genera of Echinasteridae, Aleutihenricia and Henricia, with a total of 12 echinasterid species, have been reported in Korea. The morphological characteristics of H. perforata are described and photographs are provided.

1992년 8월 뉴욕에서 개최된 유엔지명표준화총회에서 한국과 북한은 국제사회에서 통용되고 있는 일본해 지명의 부당성을 주장하면서 동해 표기의 정당성을 제기했다. 그러나 일본 정부는 국제사회에서 일본해는 19세기 서구에서 확립된 유일한 명칭이므로 일본해 이외에 다른 명칭을 단호히 거부하고 있다. 그동안 한일 간에 동해와 일본해를 둘러싼 논쟁과 분쟁은 지속되고 있다. 본 연구는 문제 해결의 일환으로 한일 대학생들의 동해/일본해 지명에 대한 인식을 조사 및 분석하였다. 그 결과 한국의 대학생들은 일본해 지명에 대해 좋지 않은 이미지와 감정을 가진 것으로 드러났다. 그리고 국제사회의 표준 지명으로 한국의 대학생들은 동해를 선호하고, 일본의 대학생들은 동해/일본해를 가장 선호하는 것으로 나타났다. 게다가 이 문제의 해결 방안으로 한일 대학생들은 공통적으로 한일 정부의 논의에 가장 많이 응답했다.

본 연구는 51년 장기(1967-2017년) 수온 관측자료와 ONI(Oceanic Niño Index)를 이용하여 El Niño와 La Niña가 한국 동해 연안용승 발생에 미치는 영향을 파악하였다. 수온의 시계열분석 결과 하계 연안용승 발생빈도가 동해남부(울기~감포) 연안에서 가장 높았다. 하계 ONI 가 2.5 이상 급감하는 연변동이 발생한 1987-1988년과 1997-1998년에 동해 전 연안역(부산~고성)의 수온이 4~7 ℃ 급상승하였다. ONI가 1.5 이상으로 El Niño가 강한 1987, 1997년과 ONI가 –0.8 이하로 La Niña가 강한 1988, 1998년 동해 연안역의 수온구조가 서로 다르게 나타 났다. El Niño가 강한 시기 연안해역의 이상 수온은 음의 값으로 비교적 차가운 냉수괴가 분포한다. 이는 수온 경계층경사(Baroclinic tilting) 가 강해 연안역의 수온 성층 형성 수심이 얕아지기 때문이다. La Niña가 강한 시기는 El Niño가 강한 시기와 반대로 이상 수온은 양의 값으 로 수온이 높게 나타났다. 또한 수온의 경계층경사가 El Niño가 강한 시기에 비해 약해 수온 성층이 El Niño가 강한 시기보다 깊은 곳에 형 성된다. El Niño가 강한 시기 얕은 수심에 수온성층이 형성되는 현상은 하계 남풍계열의 바람에 의한 연안용승이 발생할 확률을 높일 수 있다. 반대로 La Niña가 강한 시기에는 남풍계열의 바람이 지속적으로 불어도 연안용승이 발생할 확률이 작다. 왜냐하면, 수온성층이 El Niño가 강한 시기에 비해 깊은 수심에서 형성되기 때문이다.

Asteroid specimens were collected using fishing nets from the East Sea, Korea. The specimens were identified as Solaster paxillatus Sladen, 1889, belonging to the family Solasteridae of the order Valvatida. This species can be distinguished from three other Korean Solaster species by having 10 arms; subambulacral spines comprising four or five near base of arm, six or seven in middle part, and five or six in distal part of arm; furrow spines comprising four or five near basal part and three or four in distal part of arm; and suboral spines comprising more than ten spinules. The morphological characteristics of this species were described with illustrations. Solaster paxillatus is first reported in marine fauna of Korea.