• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.529-541
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• 2015

We examined the species composition and community structure of demersal fish in the middle and southern coastal waters of the East Sea of Korea by surveying a commercial Danish seine fishery from 2010 to 2013. We considered the waters north of $37^{\circ}N$ as middle and those south of $37^{\circ}N$ as southern waters. A total of 79 demersal fish species belonging to 18 families were collected. Of these, 59 species (77.6%) inhabited only the East Sea as opposed to the West and South Seas of Korea, and most were resident species. The species and biomass were similar between the two portions of the study area. The sandfish Arctoscopus japonicus (78.0%) and the blackfin flounder Glyptocephalus stelleri (65.1%) were the most common species and accounted for the most biomass in the middle and southern waters, respectively. Fish were most abundant at shallow depths (50-100 m) in the middle portion of the East Sea. Using a cluster analysis, we divided the species composition and community structure at the sampling stations into three groups: middle portion (group A), deep area of the southern portion (group B), and shallow areas of the southern portion (group C). A. japonicas and G. stelleri were dominant in groups A and B, while G. stelleri and Clupea pallasii were dominant in group C.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.3
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• pp.255-263
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• 2014

We investigated the reproductive characteristics of Lycodes tanakae in the coastal waters of the middle East Sea to elucidate the species' population structure. We investigated Lycodes tanakae maturation and spawning based on samples collected by Danish seine and gill nets from January 2012 to December 2013. We analyzed monthly changes in maturity stage, gonadosomatic index (GSI), egg diameter, fecundity, and total length at 50% group maturity. The spawning period was December to February, while fecundity ranged from 1,677 eggs at 57.3 cm (total length;TL) to 6,445 eggs at 75.7 cm. The relationship between TL and fecundity (F) was $F_e=6E-05TL^{3.127}$ ($R^2$ = 0.516), and F increased with increasing TL. We estimated the TL at 50% group maturity as 60.4 cm for females and 59.8 cm for males. This study is the first report of Lycodes tanakae reproductive characteristics in the coastal waters of the middle East Sea.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.1053-1062
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• 2015

This research assesses the implementation of the bilateral fisheries order of the China-Japan fisheries agreement. After establishment of UNCLOS, the China-Japanese fisheries agreement has played as a basis for the fisheries order in the East China Sea. The China-Japanese fisheries agreement intends that the fisheries industries in China and Japan can utilize the renewable natural resources in the East China Sea. As the EEZ of China overlaps with that of Japanese in the East China Sea, the two countries established the China-Japan Provisional Measure Zone and Middle Zone in the Sea. Even though the three coastal States (e.g. Korea, China, and Japan) in the East China Sea are involved in managing these zones, there has been little effort to coordinate each county's management. Additionally, the Taiwan-Japan fisheries agreement, which is for the area of N $27^{\circ}$, has made costal States to establish and implement united measures to conduct effective fisheries management. Regarding access to the joint fishing zone in EEZ, Chinese fisheries regulations have been enforced in the zone because the fishing capacity of China exceeds all of other countries, reducing the number of fishing licenses and catch quotas. It turned out that a nation that has authority over fisheries resources tends to establish specific conditions of fishing operations to maximize its national interest. In the China-Japan Provisional Measure Zone, Chinese and Japanese authorities have introduced united measures to manage fisheries resources. However, in the Middle Zone between China and Japan, there is no regulation on fishing; both countries' fishing vessels can have free access to the zone. Thus, it is recommended that one should introduce an international fisheries management regime for the Middle Zone. In this regard, Korea should play a leading role in establishing the international management regime because Korea has middle position in terms of geographical standpoint, the degree of dependence on commercial fishing, and its fishing capacity.

• Journal of the Korean Institute of Navigation
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• v.14 no.2
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• pp.61-76
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• 1990

It was found that three different water masses were vertically situated in the western channel of the Korea Strait in summer. Of these water masses , the origin and inflow path of the middle water were discussed and estimated by comparing with water characteristics of neighbouring sea. As a result, (1) the middle water is formed on the continental shelf in the East China Sea by the mixing of the Kuroshio Water and Chinese Continental Coastal Water, (2) the middle water seems intruded through the sea around 127 E west off Kyushu Island and east off Cheju the Island.

• Animal Systematics, Evolution and Diversity
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• v.38 no.4
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• pp.205-213
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• 2022

A new free-living marine nematode, Chaetonema longicorpus sp. nov., was discovered in a subtidal benthic habitat around the Uljin nuclear power plant in the East Sea. Chaetonema longicorpus sp. nov. differs from other Chaetonema species in its very long body length, relatively long cephalic setae, long and narrow buccal cavity, bottle-shaped amphideal fovea, short spicules, only one pre-cloacal seta instead of a pre-cloacal supplement, and conspicuous ventral swelling at the middle of the tail. Herein, we provide a taxonomic description and illustrations of this new species using differential interference contrast microscopy. Furthermore, an illustrated pictorial key to all valid species, including the new species and comparative tables on the biogeographical and morphological characteristics of the genus Chaetonema, are provided.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.3
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• pp.131-141
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• 2013

Stock identification of Todarodes pacificus collected in the East Sea, Yellow Sea and East China Sea during the period from September to December in 2011 was analyzed by morphometric characters and mitochondrial DNA (mtDNA) cytochrome oxidase subunit I (COI) gene nucleotide variations. Frequency distributions of mantle length was analyzed by morphological method with measuring size of T. pacificus. Then each stock was estimated to confirm their maturation for mean mantle length comparing with mean mature mantle length 20-22 cm. According to morphologic stock identification, it is estimated that the northern part of East Sea is categorized as summer stock and the rest parts, including mid /southern part of the East Sea, northern part of the East China Sea and northern part of the West Sea were autumn stock. For genetic analysis, a total 49 haplotypes were defined by 33 variable nucleotide sites. From the extensive haplotype diversity, limited nucleotide diversity and star-like shape of haplotype network, T. pacificus appears to have undergone rapid population expansion from an ancestral population with a small effective population size. Although pair-wise Fst estimates which represent genetic difference among groups were low, there are relatively remarkable difference of Fst between middle and southern part of the East Sea. Although middle part of the East Sea and southern part of the East Sea were situated at the East Sea, genetically separated groups were appeared.

• Korean Journal of Ichthyology
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• v.32 no.4
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• pp.245-250
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• 2020

Two specimens (407~438 mm in standard length) of a pleuronectid Atheresthes evermanni were collected by a gill-net from the coastal waters off Goseong-gun, middle East Sea of Korea. These specimens are characterized by a large mouth, narrow interorbital space, invisible eye at blind side, long and slender gill rakers, emarginated caudal fin, and almost straight lateral line. This is the first record of A. evermanni in Korean waters; we therefore add it to the Korean fish fauna and propose new Korean name, "Hwa-sal-chi-ga-ja-mi-sog" for the genus and "Hwa-sal-chi-ga-ja-mi" for the species, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.4
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• pp.306-315
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• 2005

The distribution and composition of marine floating debris were recorded from a training ship 'Kyeongyang' of Gangwon Provincial University at May 19-29, 2004 and Aug.24-31, 2004. The sampled area is the middle part of East Sea of Korea(the coast of Gangwondo and region of Ulleung island and Tokdo), divided into 27 unit segments on survey areas. Debris fabrication materials were categorized with 6 items using the following; styrofoam, paper & cardboard, net & rope, vinyl & plastic, floating metal & glass, man-made or natural wood. From the investigation on May,2004, total numbers of marine floating debris in the middle part of the East Sea of Korea was 996 individuals. The No. 1 and No. 2 unit segment located at south-west region of Ulleung Island showed higher density than others. The styrofoam and vinyl & plastic accounted for 72.8% of all debris fabrication materials. From the investigation on August, 2004, total numbers of marine floating debris in the coast of the Gangwondo of Korea was 2,473 individuals. The No. 13 and No. 14 unit segment located at the vicinity of Samcheok showed higher density than others. The styrofoam and vinyl & plastic amounted to 76.1%. In the coast of the Gangwondo, the vinyl & plastic showed the highest density of 6 items were 41.3% and 68.0% on May and August, respectively. The total numbers of marine floating debris on May and August were 3,399 individuals. Vinyl & plastic accounted for 59.4%(2,019 ind.) among all debris, next styrofoam 15.8%(537 ind.) and wood 11.2%(379 ind.).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.843-850
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• 2013

The feeding habits of Lycodes tanakae Eelpout were studied with 722 specimens collected from March 2011 to December 2012 in the coastal waters of the middle East Sea. The main prey of L. tanakae were fish, molluscs and arthropods. Nevertheless annelida, echinodermata and others were found in small amounts in the stomach contents. The L. tanakae stomach was empty of contents in 50.9% of specimens. While smaller size specimens of L. tanakae (less than 40 cm) fed mainly on euphausiids and amphipods, the larger specimens (more than 40 cm) fed on the fish Allolepis hollandi and Icelus cataphractus, and the molluscs Berryteuthis magister and Watasenia scintillans. The main prey items of L. tanakae varied seasonally. The fish Lycodes nakamurai was the dominat prey from November to January during its spawning season. Euphausiids and amphipods of the arthropods were the dominant prey from February to April. The molluscs Berryteuthis magister and Watasenia scintillans were the dominant prey from May to September. The diversity index (H') of diets showed variations by length class and month; the highest values were 2.61 in the length class of 51-55 cm, and the monthly highest were 2.68 in September with 23 species and 2.65 in November with 18 species. The highest dominance index (D') of diets was 0.57 in the length class of 31-35 cm, and the monthly highest was 0.71 in February. Cluster analysis divided prey groups into four groups by length class and three groups by monthly prey items. The gonad index gradually increased during the process of maturation while, contrary, stomach content index decreased during this period.

• Acta Via Serica
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• v.3 no.2
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• pp.23-48
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• 2018

The Silk Road usually implies a network of trade and communications that stretched from east to west and connected China and the countries of the Far East via Central Asia and the Middle East to the eastern Mediterranean, or through the northern coast of the Caspian Sea and the Volga basin to the Black Sea coast. However, at certain historical stages, a network of maritime and overland routes stretching from north to south, commonly called the Volga-Caspian trade route, also played a significant role in international trade and cultural contacts. The geopolitical realities of the early Middle Ages relating to the relationship of Byzantium, the Sassanid Empire, and the West Turkic Khaganate, the advance of the Arab Caliphate to the north, the spread of Islam in the Volga region, the glories and fall of the Khazar State, and the Scandinavian campaigns in the Caucasus, closely intertwined with the history of transport and communications connecting the north and south through the Volga-Caspian route. In a later era, the interests of the Mongolian Uluses, and then the political and economic aspirations of the Ottoman Empire, the Safavid State, and Russia, collided or combined on these routes. The article discusses trade contacts existing between the north and the south in the 15th and first half of the 17th century along the routes on the western coast of the Caspian Sea.