• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.60 no.3
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• pp.217-227
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• 2024

To analyse and review the fishing performance and species composition according to the size of the entrance and mesh of the pot in the southern coastal waters (Tongyeong, Gyeongsangnam-do and Yeosu, Jeollanam-do), the experiment in this study caught one class, eight orders, 17 families, 23 species, 662 fishes, and 99,833 g. The largest number of fish species was Conger myriaster (301 fishes caught) accounting for 45.5%, followed by Octopus vulgaris (152) accounting for 23.0%, Charybdis japonica (45) accounting for 6.8%, Sebastiscus marmoratus (43) accounting for 6.5%, and Parapercis sexfasciata (42) accounting for 6.3%. Conger myriaster, Octopus vulgaris, Charybdis japonica, Sebastiscus marmoratus, and Parapercis sexfasciata accounted for 88.1% of the total catch. For other fish species, 68 fishes of 18 species were caught, accounting for 12.5% of the total. As a result of the total catch survey, the catch rate of Conger myriaster was the highest at 50.9% in B. 22 mm/280 mm. In addition, the average total length per fish increased as the entrance size increased. The weight ratios of Conger myriaster, Octopus vulgaris, and other fish species based on the total weight caught in each pots of the six species of test fishing gear are as follows. A pots 66.6%, 26.5%, 6.9%, B pots 57.2%, 24.5 %, 18.3%, C pots 43.2%, 31.5%, 25.3%, D pots 7.4%, 56.7%, 35.9%, E pots 43.6%, 0%, 56.4%, and F pots 5.0%, 79.6%, 15.4%.

• Journal of the Korean Institute of Rural Architecture
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• v.26 no.3
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• pp.1-9
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• 2024

This study aims to estimate the cover classification and carbon respiration of halophytes based on the issues of utilising blue carbon in recent context of climate change. To address the aims, the study classified halophytes(Triglochin maritimum L and Phragmites australis), Intertidal(non-vegetated tidal flats) and Supratidal(sandy tidal flats) to measure carbon respiration and classify cover. The results are revealed that first, the carbon respiration in vegetated areas was less than that in non-vegetated areas. Second, the cover classification could be divided into halophyte communities(Triglochin maritimum L, Phragmites australis), Intertidal and Supratidal by NDWI(Moisture Index, Normalized Difference Water Index) Third, the total carbon respiration of blue carbon was calculated to be -0.0121 Ton km² hr^-1 with halophyte communities at -0.0011 Ton km² hr^-1, Intertidal respiration at -0.0113 Ton km² hr^-1 and Supratidal respiration at 0.0003 Ton km² hr^-1. As this challenge is a fundamental study that calculates the quantitative net carbon storage based on the blue carbon-based marine ecosystem, contributing to firstly, measuring the carbon respiration of cordgrass communities, reed communities, and non-vegetated tidal flats, which are potential blue carbon candidates in the study area, to establish representative values for carbon respiration, secondly, verifying the reliability of cover classification of native halophytes extracted through image classification technology, and thirdly, challenging to create a thematic map of carbon respiration, calculating the area and carbon respiration for each classification category.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.137-147
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• 2006

This is an experimental study on the properties and the strength development of concrete using of the oyster shells as a substitute fine aggregate of concrete. For this purpose, the fundamental experiments of the materials and the main factors on it were considered and then the workability and many kinds of strength about the specimens were also studied. As the experimental results, there were strength differences of less than 10% between concrete with oyster shells and normal and the most excellent grain size of oyster shells is 5.0mm and less with taking uniformly and the percentage of practicable substitution of them to fine aggregate about 30%. This paper also represents the relationship equations among many kinds of strength and elastic modulus of concrete with the oyster shells decreased with increase in proportion of oyster shells and curve of it is similar about the percentage of substitution of 10%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.397-409
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• 2024

To evaluate the recent trophic state of Jinhae Bay, field campaigns were conducted in June and August during 2020-2023, measuring environmental factors in both the surface and bottom layers. Temperature differences between layers were greater in August than in June. Surface salinity was decreased in August, probably due to runoff, while bottom salinity remained stable. Dissolved oxygen levels showed a more pronounced stratification in August, leading to hypoxic conditions in the bottom layer. Chemical oxygen demand (COD) was higher at the surface, with rainfall contributing to elevated levels. The eutrophication index (EI) was consistently higher at the bottom across all stations, driven by dissolved inorganic nitrogen (DIN) and phosphate (DIP), with a notable increase in August due to organic matter decomposition. The trophic index (TRIX) was also higher in the bottom layer, with surface TRIX influenced by DIN and salinity, and bottom TRIX by salinity, rainfall, COD, and DIN. The average TRIX for Jinhae Bay was 4.21±1.30, classified as "poor", but comparable to values from other regions. Continuous monitoring of the trophic state is essential for the sustainable management of Jinhae Bay's fisheries.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.467-478
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• 2024

The fish assemblage characteristics in the coastal waters of Sinchang-ri in the Western region of Jeju Island were determined using trammel net samples collected from 2012 to 2022. During the survey period, 81 fish species (43 families, 12 orders) were identified. Tetraodontiformes (4 families, 9 species) and Perciformes (26 families, 57 species) accounted for 84% of the total number. Annual species variation was highest in 2017 and 2019 (36 species) and lowest in 2015 (26 species). Seasonal species variation was higher in summer (peak, 58 species) than winter (peak, 41 species). The number of individuals (1,509) and biomass (446.5 kg) peaked in August (summer) and were lowest in February (winter; 415 individuals, and 150.7 kg). 41 (50.6%) subtropical fish species were identified, and the number of species was highest in 2020 {21 (61.8%) and lowest in 2014, 2017 [16-18 (47.1-47.4%)]}. Subtropical fish species, individuals and biomass were significantly correlated with environmental factors (summer temperatures) at the sampling sites. Scarbreast tuskfish Choerodon azurio, balloon fish Diodon holocanthus, flag fish Goniistius zonatus, bluestriped angelfish Chaetodontoplus septentrionalis, hairy stingfish Scorpaenopsis cirrhosa, threeline grunt Parapristipoma trilineatum, and blackfin sweeper Pempheris japonica were the dominant species of subtropical fish in the study sites.

• Korean Journal of Ichthyology
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• v.36 no.3
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• pp.253-262
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• 2024

This study revealed the reproductive biology of the Olive Flounder, Paralichthys olivaceus, in the middle of the West Sea of Korea. We collected samples using stow net and drag net fisheries in coastal waters from January to December 2023. Monthly gonodosomatic index and maturity stage results showed that the spawning period was April to June for females and March to June for males. Females grew faster than the males. The fecundity ranged from 90,387 to 994,658 number of eggs, and the relationship between TL and fecundity (F) was 0.01TL^2.4896 (R²=0.2862). The gonadosomatic index (GSI) exhibited its highest values in May for females and in March for males, coinciding with the primary spawning period. The total length required for 50% sexual maturity was determined through a logistic regression model and the females was estimated to be 49.4 cm and the males was estimated to be 36.5 cm.

• Journal of the Health Care and Life Science
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• v.11 no.2
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• pp.465-470
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• 2023

This study aims to understand marine therapy through an overall review of the marine therapy industry and provide basic data for policy establishment on marine therapy based on this. Talasotherapy refers to the medical use of marine climate, seawater, marine mud, algae, sand and other marine extracts, which are beneficial components of the ocean for preventive and therapeutic purposes. Centers in Taean, Goseong, Uljin, and other marine healing pilot projects should be well combined with programs within rehabilitation clinics so that local tourism and marine healing programs can be combined, and how well the existing marine infrastructure is established is a very important factor. Establish legal and institutional foundations, inter-ministerial and central-local cooperative governance by reorganizing laws and regulations related to marine healing and establishing a cooperative system between ministries and regions. It is necessary to expand the function of the marine therapy R&D project to play a role as a marine therapy center for each coastal region.

• Ocean and Polar Research
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• v.45 no.4
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• pp.201-209
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• 2023

Melosira nummuloides (KNU-HAPCC-101), which is a biological resource for fucoxanthin extraction, was separated from single cells, and optimal growth conditions were derived according to temperature, salinity, light intensity, light emitting diode, N:P ratio of culture medium, and dilution ratio of culture medium. These parameters were assessed to ascertain the best culture conditions for the most economical and efficient indoor mass production. The specific growth rate was the highest at 25℃ in temperature, but there was no significant difference between 15℃ and 20℃. M. nummuloides died at 0 psu in salinity, and the specific growth rate was the highest at 30 psu in respect to salinity. The light intensity was similar in all experimental groups except for 5 µmol photons m^-2 s^-2. The maximum biomass and specific growth rate in the light-emitting diode experiment were revealed at the red wavelength, but the concentration of chlorophyll-a was the lowest at the red wavelength whereas the white wavelength produced the highest chlorophyll-a concentration. In the experiment according to the ratio of nitrogen and phosphorus (N:P) based on the f/2 culture medium, the growth rate was significantly higher in the 15:1 to 50:1 ratio range. The growth rate according to the dilution concentration of the f/2 culture medium was the highest in the f/2 culture medium, but did not show a significant difference from the f/4 culture medium. M. nummuloides can be mass-cultured under conditions of a temperature of 15-25℃, a salinity of 15-35 psu, light intensity of 25-150 µmol photons m^-2 s^-2, and f/4 media concentration level with an N:P ratio 15:1 or more. Based on the data of this study, it is expected that fucoxanthin can be produced in a highly efficient manner through the development of a mass culture system.

• Korean Journal of Ichthyology
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• v.24 no.3
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• pp.201-219
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• 2012

The estuaries bank of Nakdong River, Korea, was constructed in 1987 and many arguments have been under discussion on the subject of ecological impact on ecosystem during 20 years. In this context, however, it was not focused on the role of fish-way and the way of improvement to promote fish movement to complete its life history. This paper was the result of investigation on fish fauna of upper and lower part of the bank and the analysis of comparison of the fishes with those using fish-way which were installed in each side of bank as ladder type and fish gate. The authors discussed the importance of fish gate and its management base on the result. The number of fishes collected in this study for upper part of estuaries bank was 31 species, among them 71% was the pure freshwater residents indicating the characteristics of the area as a freshwater ecosystem. It was observed that 9 species of coastal fishes were found in this region including Coilia ectens and Neosalanx sp. which is anadromous to spawn. Excluding 6 freshwater fishes, 30 fish species collected in lower part of estuaries bank were coastal fishes indicating that former brackish ecosystem was changed into marine one. The freshwater fishes found in this region were restricted the appearance only in the season of discharging freshwater into the sea. The number of fishes found in fish-way was 39 species, more than that of river and coast. But only 19 species founded in fish ladder was comparable with the result of investigation on fish gate including 32 species. It was considered that the fish gate has more important role as a fish passage from the fact that only it allowed to movement of numerous number of fry of Neosalanx sp. and Engraulis japonicus. These results indicates that two-way movement system is more efficient than downward only one in estuaries bank for fish migration.

• Journal of the Korean earth science society
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• v.32 no.7
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• pp.832-859
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• 2011

The importance of scientific education on accurate oceanic currents and circulation has been increasingly addressed because the currents have played a significant role in climate change and global energy balance. The objectives of this study are to analyze errors of the oceanic current maps in the textbooks, to discuss a variety of error sources, to suggest how to produce a unified oceanic current map of the East Sea for the students. Twenty-seven textbooks based on the 7th National Curriculum were analyzed and quantitatively investigated on the characteristics of the current maps by comparing with both the previous literature and up-to-date scientific knowledge. All the maps in the textbooks with different mappings were converted to digitalized image data with Mercator mapping using geolocation information. Detailed analysis were performed to investigate the patterns of the Tsushima Warm Current (TWC) in the Korea Strait, to examine how closely the nearshore branch of the TWC flows along the Japanese coast, to scrutinize the features of the offshore branch of the TWC south of the subpolar front in the East Sea, to quantitatively investigate the northern range of the northward-propagating East Korea Warm Current and its latitude turning to the east, and lastly to examine the outflow of the TWC near the Tsugaru Strait and the Soya Strait. In addition, the origins, southern limits, and distances from the coast of the Liman Current and the North Korea Cold Current were analyzed. Other erroneous expressions of the currents in the textbooks were presented. These analyses revealed the problems in the present current maps of the textbooks, which might lead the students to misconception. This study also addressed a necessity in a bridge between scientists with up-to-date scientific results and educators who needed educational materials.