• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.5
• /
• pp.618-623
• /
• 1999

A relationship between SST (Sea Surface Temperature) fronts and formation of fishing grounds was examined using the data on fishing conditions obtained from 41 Korean purse-seiners during the period of 1991 to 1996. Good fishing grounds observed in the southern sea of Korea and the nothern area of the East China Sea were yearly found around the frontal zone and around the marginal area of Tsushima Current which was the periphery of fronts, Also, there were several fishing grounds, which are not related to the fronts. They can be classified into the following four types : The first type was found in the warm water pocket located in the western area of Cheju Island in winter. The second type was made in a intensive bending of isobathytherm with a higher temperature in the main stream of Tsushima Current between Cheju Island and the Goto Islands in winter. The third type was formed by the topographical vortex motion near the Tsushima Island in winter and spring. The fourth type was found at the area of the reflow Sea Warm Current in southwest sea of Korea between the costal front zone and the Yellow Bottom Cold Waters in summer and autumn.

• International Area Studies Review
• /
• v.13 no.2
• /
• pp.226-253
• /
• 2009

The study analyzes the trend of regional economic development disparity in China, sets up research period from 1952 to 2008, and uses the after-modified regional GDP data by the first national economic census in 2004. The results as follow. Firstly, the Coefficient of variation(CV) with after-modified GDP data lower than the pre-modified data. Secondly, generally speaking, after-reform and open period's disparity lower than pre-reform and open period. In particular, the regional development disparity increased slowly after 1990, not rapidly. Third, the new cycle of the inverse-U type is appeared from 2002. Fourth, compared with Herfindhal-Hirschman index(HHI) and Theil Entrophy index(TEI), the lower level regions more affect to reduce the disparity in 1980s, and it also affect to reduce the disparity after 2000. Fifth, the convergence hypothesis test finds that the regional economic development disparity has been converged in 1978-2008. Sixth, the inverse-U type hypothesis not has statistical significance, from 1952 to 2008, but it has statistical significance from 1991 to 2008. This result same as the CV and the convergence test.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.2
• /
• pp.220-228
• /
• 2019

To determine the horizontal and temporal distribution of common squid larvae, Todarodes pacificus (hereafter T. pacificus), we conducted surveys using an IKMT net (mesh size: $500{\mu}m$) with a Fisheries Research Vessel (FRV, TAMGU 21) in the southwestern part of the East Sea in summer (August and September) and autumn (November) 2015. A total of 228 larvae, ranging in mantle length (ML) from 1.4 mm to 21.9 mm, were collected at 35 stations over the research period. The monthly average mantle length of T. pacificus larvae did not differ significantly in August, September and November. (p > 0.05). Catch densities at positive stations ranged between 0.1 and $7.9inds./1,000m^3$ over the research period. Incidence rates of T. pacificus larvae were similar over three months, in the study area (62.9 % - 68.6 %). The 4 - 5 mm mantle length range had the highest frequency in size-frequency distributions for T. pacificus larvae. The larval survival temperature ($15-24^{\circ}C$) at positive stations for catch densities was located below a 20 m depth in August whereas it was located at the surface of the water in September and November. The survival temperature for larvae existed from the bottom to the surface of the water where larvae were sampled larvae in shallow sea areas. However, the larval survival temperature occurred in a shallower location than the upper layer of the thermocline in deep sea areas at a depth below 100 m.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.4
• /
• pp.459-468
• /
• 2022

Long-term data analyses and bioassay experiments were conducted to assess limiting nutrients in Cheonsu Bay and Taean sea. First, long-term nutrient data (2004-2016) provided by the National Water Quality Monitoring Network were used to assess potential limiting nutrients. Analysis of the long-term data showed that the dissolved inorganic nitrogen/dissolved inorganic phosphate (DIN/DIP) ratio was mostly below 16, with N limitation being dominant. A subsequent analysis using the concentration ratios of N, P, and Si showed that N limitation was dominant during summer and autumn but that Si limitation occasionally occurred during winter and spring in relatively limited areas. However, the dominant limiting nutrient was not determined. The nutrient analysis of the field water collected during the bioassay experiment showed that DIN/DIP revealed P limitation at all stations in March and May, whereas N limitation was dominant in July and October. In the analysis using the concentration ratios of N, P, and Si, P and Si limitation appeared in March and May, but there were points with no dominant limiting nutrient. However, N limitation was dominant in July and October. In the bioassay experiment for assessment of the actual limiting nutrient, the results showed no specific limiting nutrient in March, whereas NH₄⁺ and NO₃^- showed responses in May, July, and October, which confirmed that N was a substantial limiting nutrient directly involved in phytoplankton growth during this period.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.4 no.1
• /
• pp.80-88
• /
• 2002

This study was carried out to investigate the native distribution and flowering characteristics of Lycoris genus which is endemic species in Asia. This study was summarized as fellows: Native distribution of Lycoris genus was situated in latitude 37- 24 degrees with high humidity of coastline. Mininum temperature of native area was at -10℃ during winter season. The leaf of L. squamigera, L. koreana, L. sangunea, L. sprengeri, L. incanata and L. flavescens emergenced in spring. The leaf of L. radiata, L. rdiata var pumila, L. aurea, L. traubii, L. albiflora and L. houdyshelli emergenced in autum. Bulb of Lycoris genus show a sympodial branching system which is composed of 14-23 scales and 2.8-5.2 leaves per each bulb at flowering time. The flower shape of L. squamigera, L. Koreana, L, aurea, L. incanata, L. sprengeri, L. sanguinea and L. flavescens was trumpet. The flower of L. radiata. L. radiata var pumila, L. albiflora, L. houdchelli and L. traubii. was spider.

• 지역과문화
• /
• v.6 no.2
• /
• pp.77-104
• /
• 2019

This study examines the efficiency of using local cultural resources in local governments. The study does so by DEA(Data Envelope Analysis) using data from the year 2017 for 17 local governments in Korea. In addition, this study tries to estimate environmental efficiency of local cultural resources. For this, the 'Total Efficiency' including the output variables related to the local cultural resource environment was analyzed. After than It compared the 'Total Efficiency' with the 'Utilization Efficiency', to estimate the 'Environmental Efficiency' of local cultural resources. The followings are results which are significant statistically. Firstly, it was evaluated that five of the 17 local governments utilized the local cultural resources efficiently. Secondly, it was result that the inefficiency of the other local governments was relatively influenced by the economies of scale than PTE(Pure Technical Efficiency). Thirdly, It has been confirmed that environmental aspects such as cultural properties and cultural infrastructure have a considerable impact on the increase or decrease of efficiency in local governments. The difference in the efficiency of local governments are influenced by the population density. In order to improve the efficiency in the future, it is necessary to adjust the appropriate level of input according to the local population estimate, which is a major consumer of the local cultural resource utilization. In addition, the local festivals and village festivals held by local governments should be checked to improve in quality by eliminating inefficiencies. Also, it should be considered of environmental factors together, when analyzing the efficiency of the local cultural resource in local governments.

• Korean Journal of Ichthyology
• /
• v.35 no.4
• /
• pp.325-332
• /
• 2023

The feeding habits of the Fat Greenling Hexagrammos otakii were studied using 376 specimens (17.4~41.4 cm in total length) collected off the Incheon coast, Korea between March 2020 and February 2021. H. otakii ate mainly gastropoda and teleostei, incuding caridea, brachyura, polychaeta, cephalopoda and amphipoda. The diet composition of H. otakii showed changes in season. H. otakii ate mainly cephalopoda in spring and ate mainly polychaeta in summer. The teleostei feeding rate was highest in autumn, whereas the proportion of gastropoda was higher in winter than in other seasons. The mean number of preys per stomach (mN/ST, One-way ANOVA, F=2.026, P>0.05) and mean weight of preys per stomach (mW/ST, One-way ANOVA, F=1.075, P>0.05) didn't show a statistically significant difference among size classes.

• Korean Journal of Ichthyology
• /
• v.35 no.4
• /
• pp.305-312
• /
• 2023

Diet composition and feeding strategy of the largehead hairtail, Trichiurus japonicas were studied using 375 specimens collected by purse seine, set net fisheries and lure fishing from February 2021 to January 2022 in the southern sea of Korea. The anal length (AL) of these specimens was from 3.4~49.0 cm. T. japonicus fed majorly on Fishes (especially Engraulis japonicus) based on ranking index (%RI=99.3). Fishes were the main prey items for all size classes. T. japonicas also showed size-related dietary shift from E. japonicus to T. japonicus, Larimichthys polyactis and Engraulidae. Fishes were the main prey items for all seasons. The main fish prey during spring and summer was E. japonicus, but in the autumn and winter, the E. japonicus portion decreased, and T. japonicus, L. polyactis, and Engraulidae portion increased. T. japonicus were specialized feeders with E. japonicus as their dominant prey.

• Korean Journal of Environmental Biology
• /
• v.27 no.4
• /
• pp.341-352
• /
• 2009

This study was carried out to investigated community structure of macrobenthic assemblages around the Wolseong Nuclear Power Plant, East Sea of Korea and seasonal sampling was performed from October 2007 to July 2008. A total of 163 macrobenthic fauna were collected. The overall average macrobenthos density and biomass were 1,005 individuals $m^{-2}$ and $21.81\;gWWt\;m^{-2}$, respectively. Based on the LeBris (1988) index, there were 10 dominant species accounting for approximately 69.00% of total individuals. The major dominant species were the polychaetes Spiophanes bombyx (349 inds. $m^{-2}$), Mediomastus californiensis (82 inds. $m^{-2}$), Sigambra tentaculata (55 inds. $m^{-2}$), Magelona japonica (50 inds. $m^{-2}$), Scoletoma longifolia (33 inds. $m^{-2}$) and the Unidentified amphipod (Amphipoda spp., 72 inds. $m^{-2}$). The conventional multi-variate statistics (cluster analysis and non-metric multi-dimensional scaling) applied to assess spatial variation in macrobenthic assemblages. Cluster analysis and nMDS ordination analysis based on the Bray-Curtis similarity identified 2 major station groups. The major group 1 was associated with sand dominated stations and was characterized by high abundance of the bivalves Mactra chinensis, Siliqua pulchella and the polychaete Protodorvillea egena. On the other hand, major group 2 was connected with mud dominated stations and was numerically dominated by the polychaetes M. californiensis, M. japonica, Sternaspis scutata, S. longifolia and the bivalves Thyasira tokunagai and Theora fragilis. However, macrobenthic community structure were no significant differences between the environmental variables (sediment type and depth) and heated discharge.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.16 no.4
• /
• pp.305-315
• /
• 1983

A survey was carried out from July to December in 1979 and 1982 for the investigation of oceanographic conditions and phytoplankton in Seogwipo coastal area. Although a peculiar coastal sea water is formed by in flowing of fresh water, this is developed mainly in summer and disappeared or weakened in its strength after November. However, this coastal sea water covers only the surface while in mid and bottom layer open sea water is approached to the coast. Therefore, coastal and open sea water appears simultaneously in narrow sea area. Mean values of nutrient concentrates on surface layer during investigating period were $3.72{\sim}16.34{\mu}g-at/l$ in silicate, $1.98{\sim}5.53{\mu}g-at/l$ in nitrate and $0.34{\sim}0.90{\mu}g-at/l$ in phosphate. These showed slight differences among places but in general coastal side were lower than open sea side. Phosphates which is the lowest in concentrates among nutrients in Seogwipo coastal area shows almost similar value with Jinhae Bay but higher than open sea water around 10 mile south of Seogwipo. In general, seasonal changes of nutrients in investigating period shows a tendency of the lowest in October, increasing in November, and again slight decrease in December. As a phytoplankton fauna, 48 species, 1 variety and 2 breeds of Diatoms, 29 species, 3 varieties and 1 breed fo Dinoflagellates, and 1 species each of Chroococcus and Trichoceratium were found. Monthly predominant species are all neritic: Rhizosolenia sp. and Ceratium sp. in August, Chaetoceros sp., Ceratium sp. and Peridinium sp. in September, Astrionella sp. and Peridinium sp. in October, Astrionella sp., Navicula sp. and Chaetoceros sp. in November Among these, Rhizosolenia alata f. gracillima in August and Astrionella gracillima in November are remarkable predominant.