• Korean Journal of Fisheries and Aquatic Sciences
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• v.6 no.1_2
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• pp.49-57
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• 1973

Based on the fork length data of 1960 and on the fishery statistical data of 1968, 1970 and 1971, a research was made on the migration of the Pacific saury in the waters off the eastern coast of Korea. The population is divided into four groups in terms of size as shown in Fig. 5. The four groups demonstrate more or less different pattern of migration, both temporally and spatially. Northward migration is brought out in order of size, i. e., the smaller move northward earlier than the larger do, and the order is reverse in the case of southward migration. The migration routes of each size group are presented in Fig. 8. Whether the fish takes its course to the north or the south, its distribution centroid within the fishing grounds is traced in general following the line between $130^{\circ}$ and $130^{\circ}$130^{\circ$x. long., although longitudinally a pronounced annual bias is found in its month position. The moving pattern of the distribution centroid is assumed to be related with the abundance of each group to a considerable extent.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.23-23
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• 2023

The Hairy labrador tea (Ledum palustre L. var. diversipilosum Nakai) is a evergreen small shrub, belonging to the Ericaceae and mainly distributed along the alpine areas of Hamgyeong-do in North Korea. Through seed physiological research on North Korean plants, we intend to obtain basic data for the development of mass propagation methods and use them for vegetation restoration. The internal and external morphological characters of the seed were observed using scanning electron microscopy or stereoscopy, and full seeds were selected through X-ray test. Seeds were cultured on a growth condition at 15/6℃ and 25/15℃ to examine the germination response according to temperature, and the number of germinated individuals was examined every 24 hours to calculate germination percentage and mean germination time. Low-temperature treatment (4℃) and hormone treatment (GA3) were performed to investigate the effect of dormancy breaking, and analysis of variance (ANOVA) was performed on the experimental results using SAS 9.4. The seeds of the Hairy labrador tea were elliptical-narrow in shape, and the epidermal cell wall pattern was reticulated. The final germination rate (FGP) was the highest at 58.9% under the condition of low temperature treatment at 25/15℃. The average number of days to germination (MGT) was the highest at 25.1 days without treatment at 15/6℃, and the average of the last germination days was confirmed to be about 13 days. As a result of low temperature treatment, it was confirmed that the final germination rate (FGP) increased by 43.3%. The significance of the final germination rate (FGP) was verified according to the pretreatment at 25/15℃.

• Ocean and Polar Research
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• v.23 no.1
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• pp.35-49
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• 2001

An ichthyofauna analysis of the East Sea using quantitative investigation procedures for latitudinal variations of the species richness and clustering of the species list is presented to illustrate the application of the adopted geographical scaling (less than 1:10,000,000) which provides a principal opportunity for common benthic and pelagic biogeographical zonation. The distribution of both pelagic and benthic marine fish biota at a scale of biosphere (or its major sections) was highly influenced by spatial nonuniformity of hydrological structure associated with the various water circulations and frontal zones. Following zoogeographical zonations were established for the East Sea: Osaka, East Korea, Primorye, North Primorye, Northern East Sea, Uetsu, Tsugaru, Soya and West Sakhalin.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.1
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• pp.23-28
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• 2004

The transmittance properties of fishing lamp in stick-held dip net fishing vessel for Pacific saury was investigated during nighttime operations in the North Pacific on May 19 and 24, 2003. The incandescent lamps of red color (750W${\times}$100) and halogen lamps (750W${\times}$521) were used as a fishing lamp for gathering Pacific saury. The relative irradiance of red incandescent lamp and halogen lamp in the air showed peak in 1,052nm of wave length. However, the irradiance of halogen lamp below 600nm of wave length was higher than that of incandescent lamp. The relationship between underwater illuminance (Y) and water depth (X) of sunlight in the observation areas A (37$^{\circ}$ 11'N, 178$^{\circ}$ 46'W) and B (31$^{\circ}$ 11'N, 178$^{\circ}$ 01'E) is represented as follows; $Y=2572.2{\cdot}e^{-0.0721X},\;R^2=0.9915$ $Y=3312.4{\cdot}e^{-0.0619X},\;R^2=0.9837$ The distribution of underwater illuminance of observation areas A and B showed low value of 0.31x and 0.61x in 50m depth, respectively. In the fishing grounds of Pacific saury, the light intensity of distribution depth was above 0.51x.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.3
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• pp.203-213
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• 1991

Zooplankton samples were collected vertically from different layers with a closing net at 14 stations in the middle East Sea of Korea in February, August and September to study distribution of biological indicators for analysis of water masses. Horizontal and vertical distributions of important species of copepods and chaetognathas known as indicator species were closely related to distributions of different water masses and oceanic fronts. Pleuromamma gracilis, Calanus tenuicornis, Sagitta enflata and Sagitta minima were found to be reliable indicator species to determine warm water mass with warm core, and Calanus cristatus, Calanus tonsus and Sagitta elegans could be used as cold water species for evaluating the movement of cold current from North Korea, and Gaetanus armiger was deep sea water species. Therefore, it was found that North Korean Cold Current down to the south along the coast appeared to be significant in the surface around Chumunjin area, and from here towards the south the cold water containing S. elegans submerged under warm water with S. enflata which were about $2{\~}4^{\circ}C$ higher than that of the vicinity and reappeared near Chukpeon area in surface layer. In the layer between loom and 300m depths, distribution of Pleuromamma gracilis and Sagitta bedoti indicated that warm water mass and front zone influenced by the different water systems were formed in northwestern area off Ulreung-do. In $300{\~}500m$ layer, the proper cold water could be estimated to be present in the northwestern area off Ulreung-do throughout the survey period by the high abundance of Gaetanus armiger. In August, distributions of S. bedoti, S. enflata and S. minima were valuable index to find oceanic fronts and warm core.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.1
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• pp.59-71
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• 2012

In order to elucidate the mechanism of fishing condition variation of anchovy in the set net fisheries of Anggang Bay, the monthly catch of anchovy was analyzed and examined based on the data acquired from 2006 to 2010 in 13 different fishing grounds. Anchovy consistently appeared from April to December and reached the production of 840 to 1,424 t (average : 1,228 t), with a big annual variation. However, anchovy production in this area accounts for approximately 75% of the production by set net in Anggang Bay whereas it holds 6.8% of the nationwide production (=18,034 t) by set net. The school of anchovy starts to appear in April at the west mouth of the bay and move north-eastward. Afterward, having three of clockwise turns in the middle of the bay, they scatter to swim into the deep place of the bay and finally go out to turn back to their coming way. These behaviors of anchovy are likely related to thermal fronts as well as distributions of food. The production of anchovy (y, kg) relied greatly on frequencies of effective northeasterly ($x_1$) or northwesterly ($x_2$) wind (${\leq}$3.5m/s) which blow between April and June. Their relationships are as follows: $y=1086.27+21.499x_1-15.16x_2$ (r=0.901). Consequently, we concluded that the northeasterly wind, which appears in the breeding season of spring, played a role to retard the movement of anchovy school to the eastern sea, while the northwesterly wind inhibits the invasion of anchovy school into the bay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.6
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• pp.697-703
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• 2018

In 2017, total coliform (TC), fecal coliform (FC) and fecal Streptococci (FS) bacteria were examined in seawater samples collected at coastal sites on Jeju Island (Aewol as a control, Namwon, and Daejeong) and at Pohang (Yeongil as a control, Guryongpo-North, and Guryongpo-South) to examine the correlations between the density of fish farms and distributions of the indicator bacteria. Only a few TC, FC, and FS colonies were detected in all of the samples obtained from Jeju Island. Of note, 2,000 and 1,000 CFU of FS $100mL^{-1}$ were detected in samples from Guryongpo-South in June and August, respectively. Although the total area of approved fish farms located within 5 km of the sampling point at Guryongpo-South is 5-16 times smaller than in other regions, the number of indicator bacteria was highest in this region. Therefore, microbiological pollution in the Guryongpo-South region might be due to sources other than the effluent released from nearby fish farms.

• ALGAE
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• v.33 no.1
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• pp.55-68
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• 2018

Foliose species of the Bangiaceae (Porphyra s. l.) are very important in Korean fisheries, and their taxonomy and ecophysiology have received much attention because of the potential for developing or improving aquaculture techniques. Although 20 species of foliose Bangiales have been listed from the Korean coast, some of them remain uncertain and need further comparative morphological studies with molecular comparison. In this study, we confirm the distribution of four Pyropia species from the east coast of Korea, Pyropia kinositae, P. moriensis, P. onoi, and P. retorta sp. nov., based on morphology and rbcL sequence data. Although P. onoi was listed in North Korea in old floral works, its occurrence on the east coast of South Korea is first revealed in this study based on molecular data. P. kinositae and P. moriensis, which were originally described from Hokkaido, Japan, are first reported on the east coast of Korea in this study. Pyropia retorta sp. nov. and P. yezonesis share a similar thallus color and narrow spermatangial patches in the upper portion of the frond, and they have a sympatric distribution. However, P. retorta can be distinguished by the curled or twisted thalli and by molecular data. The biogeographic pattern of the two native species, P. kinositae and P. retorta, suggests that the east coast of Korea may have been a place of refugia during the Last Glacial Maximum (LGM), and then recolonized to the northern part of Japan through the restored East Korean Warm Current after the LGM.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.4
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• pp.206-213
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• 2013

Glass eels (Anguilla japonica) are caught in the west coast of Korea on their migratory route from the breeding grounds in the Mariana Trench along the North Equatorial Current and the Kuroshio Current. To identify the food source of natural glass eels, we analyzed the stable C and N isotopes of glass eels caught in April 2012 and investigated possible food sources in the survey area. In particular, with respect to the stable C and N isotopes of particulate organic matter, we extended the surveying area to the northern parts of East China Sea as well as the west coast of Korea. The stable C and N isotope ratios of the glass eels caught in the west coast were found to be $-20.7{\pm}0.1$‰ and $5.0{\pm}0.2$‰, respectively. The stable C and N isotope ratios of the particulate organic matter in the west coast of Korea, in which the glass eels are assumed to eat the particulate organic matter as food source, were estimated to be $-24.0{\pm}0.3$‰ and $2.8{\pm}0.4$‰, respectively. Similar data were obtained from the northern part of the East China Sea, $-24.5{\pm}0.5$‰ and $0.8{\pm}0.3$‰. The stable isotope ratios showed values differing from the stepwise increasing rates up the food web in natural aquatic ecosystem, showing that particulate organic matter in the west coast of Korea and East China Sea was not served as the glass eels food source. This result suggested that the glass eels caught in the west coast might not assimilate nutrition from the marine environment during long migration.

• Journal of Navigation and Port Research
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• v.30 no.8 s.114
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• pp.617-622
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• 2006

Gamcheon Harbor was developed to cope with increased freight demand of Busan port and supplement function of the north port. Because container wharf is opened to 1997 as well as general wharf, present maximum 50,000DWT class containerships have been incoming and outgoing. However, In Gamcheon port, small size ships such as fishing boats, miscellaneous boats account for 50 percent of the traffic and a public marine products wholesale market that is building on the north wharf will open in 2008. Therefore, it needs to grasp future year traffic volume before establishing operation plan for port management. Also, analysis on crossing situation risk is required because the breakwater entrance in Gamcheon Harbor is narrow and the crossed passing of ship is ever-present at breakwater front. Thus the traffic volume in the future was presumed and quantitative analysis was achieved on crossing situation though simulations with the traffic volume.