Coastal Waters Of Korea Research Articles

Sex-specific differences in the growth and population characteristics of Sand crab Ovalipes punctatus (De Haan, 1833) in coastal waters of Korea

The sex-specific differences in the growth and population characteristics of the high-commercial-value sand crab Ovalipes punctatus were investigated in Korea. The estimated allometric growth between the sexes showed significant differences in all morphometric measurements. In the classification of growth types, carapace width-chela length exhibited positive and negative allometric growth in males and females, respectively. Carapace width-abdominal width showed positive relative growth in both sexes, and orbital spine width exhibited negative relative growth in both sexes. Consequently, sexual dimorphism was evident in all measured traits. Growth parameters estimated using the ELEFAN function of the FiSAT II program indicated higher values in males compared to females. Asymptotic length (CW∞) for males was estimated at 139.2 mm, whereas for females it was 116.6 mm. Additionally, the growth coefficient (K) was higher in males (0.65) than in females (0.54), suggesting faster growth in males. The winter point (WP) was 1 for males and 0.7 for females, indicating slower growth in males during the colder December and slower growth in females during the spawning period in August. The modified von Bertalanffy growth curves indicated asymptotic growth in all sexes, and the growth performance index (φ') showed higher values in males (4.10) compared to females (3.87), reflecting differences in growth curves. The steady increase in recruitment rates from July to September was associated with the appearance of larvae and their subsequent growth into juveniles, leading to their recruitment into the population during this period. Therefore, O. punctatus exhibited sex-specific differences in growth parameters, suggesting distinct growth strategies between the sexes.

엘니뇨/라니냐와 한국 연안의 적조 발생 관계

엘니뇨/라니냐와 한국 연안의 적조 발생 관계

Maritime Traffic Evaluation Using Spatial-Temporal Density Analysis Based on Big AIS Data

For developing national maritime traffic routes through the coastal waters of Korea, the customary maritime traffic flow must be accurately identified and quantitatively evaluated. In this study, the occupancy time of ships in cells was calculated through a density analysis based on automatic identification system data. The density map was statistically created by logarithmically transforming the density values and adopting standard deviation-based stretch visualization to increase the normality of the distribution. Many types of traffic routes such as open-sea, coastal, inland, and coastal access routes were successfully identified; moreover, the stretch color ramp ratio was reduced to identify routes having relatively high density. Adopting a single standard deviation and demonstrating the top 25% of color ramps, the analysis afforded the main routes through which customary traffic flows. This novel density analysis method and statistical visualization method is expected to be used for developing national maritime traffic routes and should ultimately contribute to maritime safety. Moreover, it provides a scientific means and simulator for determining the navigation area and analyzing conflicts with other activities in marine spatial planning.

Spatio-Temporal Distribution of Giant Jellyfish (Nemopilema nomurai)

In this study, the distribution of giant N. jellyfish by the echo counting method was investigated in the East China Sea, where giant N. jellyfish are known to breed and migrate to the coastal waters of Korea mainly in summer. In addition, the distribution densities by the survey method were compared with the sighting and trawl surveys. In the case of the East China Sea area and the Gijang coastal area, a split beam type scientific echosounder (EK60, Simrad, Norway) and Acoustic data at 38 and 120 kHz were collected while moving at 6–7 kts. In the coastal waters of Korea, acoustics data at 38 and 120 kHz were collected with a split beam type scientific echosounder (EK80, Simrad, Norway) attached to the bottom of the R/V Tamgu No. 21. In the East China Sea, the average distribution densities of acoustic, sighting, and trawl surveys were 8355.7 (10−6 ind/m3), 162.2 (10−6 ind/m3), and 792.5 (10−6 ind/m3), respectively. The average densities in the coastal waters of Korea of acoustic, sighting, and trawl surveys were 2238.7 (10−6 ind/m3), 664.9 (10−6 ind/m3), and 432.9 (10−6 ind/m3), respectively. The average distribution density of the acoustic survey conducted on 21 July 2020 in the coastal waters of Gijang was 1024.5 (10−6 ind/m3), and the sighting survey showed 48.8 (10−6 ind/m3). The sighting surveys conducted on 22 July 2020 were 393.3 (10−6 ind/m3) and 19.6 (10−6 ind/m3). The average distribution density for the acoustic survey performed on 23 July 2020 was 99.0 (10−6 ind/m3), and for the sighting survey was 197.2 (10−6 ind/m3). When comparing the results of the acoustic survey with the results of the sighting and the trawl surveys, all surveys except for the survey conducted on 23 July 2020 showed that the acoustic survey was higher than other survey methods.

어구부표의 표시 방법 개선에 대한 입법론적 고찰 - 어구 손상사고 사례를 중심으로 -

Accidents between small ships and small fishing vessels sailing in the coastal waters of Korea and facilities installed for fishing on the coast occur frequently every year. These accidents are mainly caused by aquaculture farms, fishing nets, and gill nets installed in coastal waters. Common causes of ship accidents include the negligence of the officers of the crew on a sailing vessel, non-compliance with course maintenance, confirmation of ship position, and general navigation. It can be in various ways, such as non-compliance with the principles and regulations on the prevention of collisions at sea. In particular, to examine the cause of the accident related to the fishing net damage accident, it was analyzed through the decision of the Maritime Safety Tribunal, and as a result, the cause of the accident was neglect of the boundary, not securing an appropriate distance from the installed fishing gear, and insufficient establishment of the voyage plan. In order to reduce accidents caused by these human factors, it takes a long time and a lot of money, such as constant safety education for seafarers or changes to systems such as ship safety management system. In this paper, measures to reduce the occurrence of accidents by removing other risk factors other than human factors by intuitively discovering fishing gear a little faster are presented in 「Fisheries Act」, 「Rules on the Management of Fishing Licenses, etc.」, 「Aquaculture and fishing grounds」 We will try to find a way to reduce the damage to fishing nets by identifying and improving problems in the “Installation Standards for Marking Facilities” and “Aquaculture Industry Development Act”.

New records of five taxa of unarmored and thin-walled dinoflagellates from brackish and coastal waters of Korea

New records of five taxa of unarmored and thin-walled dinoflagellates from brackish and coastal waters of Korea

Relationship between Migratory Timing of Salmon (<i>Oncorhynchus keta</i>) into the Wangpi River and Coastal Environment of the Mid-eastern Coastal Water of Korea

Relationship between Migratory Timing of Salmon (<i>Oncorhynchus keta</i>) into the Wangpi River and Coastal Environment of the Mid-eastern Coastal Water of Korea

Vertical distribution of giant jellyfish (<i>Nemopilema nomurai</i>) in the coastal waters of Korea and its correlation a nalysis by survey method

Vertical distribution of giant jellyfish (<i>Nemopilema nomurai</i>) in the coastal waters of Korea and its correlation a nalysis by survey method

Population Variation of Spanish Mackerel (<i>Scomberomorus niphonius</i>) according to Its Major Prey Abundance in Southern and Eastern Coastal Waters of Korea

Population Variation of Spanish Mackerel (<i>Scomberomorus niphonius</i>) according to Its Major Prey Abundance in Southern and Eastern Coastal Waters of Korea

Strategic Improvement Plan to Increase the Usability of Coastal Base Maps Throughout Korea

Lee, J.-C.; Koh, Y.-C., and Lee, D.-H., 2021. Strategic improvement plan to increase the usability of coastal base maps throughout Korea. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 395–399. Coconut Creek (Florida), ISSN 0749–0208. The National Geographic Information Institute constructs and supplies coastal base maps containing spatial and geographic information. The main purpose is securing basic data for designing and developing coastal waters. However, there has been no continuous construction of information for all coastal waters in Korea; therefore, detailed and precise coastal water information for each coastal situation cannot be provided. This study introduces a continuous and unified coastal base map for all coastal waters in Korea. The introduced map can be employed to provide coastal water information with high utility, and widely used not only in coastal construction projects but also in various industries related to the spatial development of coastal waters.

Newly recorded unarmored dinoflagellates in the family Kareniaceae (Gymnodiniales, Dinophyceae) in brackish and coastal waters of Korea

Unarmored dinoflagellates, in the family Kareniaceae, include harmful or toxic bloom-forming species, which are associated with massive fish kills and mortalities of marine organisms worldwide. The occurrence and distribution of the toxigenic species in the family Kareniaceae were investigated in the brackish and coastal waters of Korea between July 2018 and October 2020. During the survey, we collected seven newly recorded species; Karenia papilionacea, Karlodinium digitatum, Karl. veneficum, Karl. zhouanum, Takayama acrotrocha, T. helix, and T. tasmanica. A total of fifteen strains of the seven taxa were successfully established as clonal cultures and examined using LM, SEM, and molecular phylogeny inferred from LSU rDNA sequences. Herein, we present the taxonomic information, morphological features, and molecular phylogenetic positions of the unrecorded dinoflagellate species collected from Korean coastal waters.

음향산란이론모델을 이용한 살오징어(Todarodes pacifica)의 음향후방산란강도 측정

Recently, Japenese common squid, an important fisheries resource, has been decreased in the coastal waters of Korea. The purpose of this study is to estimate the TS of Japanese common squid and to use it as basic data to figure out the exact amount of resources of Japanese common squid. In order to estimate the TS, the total length and mantle length of 26 common squids were measured and photographed. The samples photographed were digitized and applied to the DWBA theoretical model. In the shortest mantle length No. 10 sample, the range of acoustic backscattering target strength for each frequency was measured –101.4 dB∼–55.9 dB at 38 kHz, –91.9 dB∼–57.1 dB at 70 kHz, –99.8 dB∼–56.2 dB at 120 kHz. The acoustic scattering strength range of No. 21 sample with the longest mantle length was measured –98.44 dB∼–55.3 dB at 38 kHz, –84.9 dB∼–53.8 dB at 70 kHz, and –89.5 dB ∼–51.5 dB at 120 kHz. The TS regression equations for common squid at each frequency was as follows; 38kHzSUBMax/SUB = 20logSUB10/SUB(ML) - 71.5, 38 kHzSUBAvg/SUB = 20logSUB10/SUB(ML) – 81.5, 70kHzSUBMax/SUB = 210logSUB10/SUB(ML) – 76.9, 70kHzSUBAvg/SUB. 20logSUB10/SUB(ML) - 82.8, 120kHzSUBMax/SUB = 20logSUB10/SUB(ML) – 75.6, 120kHzSUBAvg/SUB = 20logSUB10/SUB(ML) – 83.0

Above water remote sensing reflectance dataset on the coastal waters of California and Korea

Remote sensing reflectance (R<sub>rs</sub>) is a fundamental data of ocean color remote sensing that is used as an input data for algorithm development. In this study, the Rrs spectra acquired from the coast of Korea and California, on the opposite side of the Pacific Ocean, were analyzed and compared. The waters of Gyeonggi Bay and Mokpo had a similar spectrum to those of the waters inside of the San Francisco Bay, although the waters of each region had different characteristics. The South Sea in Korea showed similar spectral characteristics on the waters of Monterey Bay and outside of the San Francisco Bay in California. The upward slope of the Rrs spectra in the range of 400 to 600 nm obtained from the inside of the San Francisco Bay was higher than the coastal waters on the Gyeonggi Bay and Mokpo in Korea. The Rrs spectra showing peaks on 580 nm and 680 ~ 700 nm due to chlorophyll were similarly observed in the South and East Seas of Korea, and the coastal waters of Monterey Bay and the outside of the San Francisco Bay in California.

Estimating Age-Specific Natural Mortality for Sandfish in the Eastern Coastal Waters of Korea

To estimate age-specific natural mortality, we proposed an age-structured biomass model with an impulsive dynamical system. In the estimation of natural mortality, we considered growth rate and also reproduction rate, growth, and catch of sandfish, Arctoscopus japonicus. Assuming a linear relationship between observed values of the catch per unit effort (CPUE) and total biomass estimated by the age-structured biomass model, we estimated the age-specific natural mortality using the CPUE and catch data, from 1994 to 2009, for varying values of the assumed initial total biomass in 1994, by selecting the largest coefficient of determination (R2). We suggested the following empirical formula: Mi=qKL∞ln(eK(i+1−t0) − 1eK(i−t0) − 1), which estimated natural mortality of sandfish, and the derived age-specific natural mortality was significantly related to fecundity and growth. The parameters of von Bertalanffy growth equation and a logistic equation of maturity with total length were derived from the data of otolith and gonad analysis of female sandfish collected from 2005 to 2008 and from 2005 to 2006, respectively. We also conducted sensitivity analysis by varying the exponent in the inverse function of total length.

Study on the mesh selectivity of a drum shaped pot for finely-striate buccinum (<i>Buccinum striatissimum</i>) in the eastern coastal waters of Korea

Study on the mesh selectivity of a drum shaped pot for finely-striate buccinum (<i>Buccinum striatissimum</i>) in the eastern coastal waters of Korea

Maturation and Spawning of Yellowback Seabream Dentex tumifrons in the Coastal Waters of Korea

Maturation and Spawning of Yellowback Seabream Dentex tumifrons in the Coastal Waters of Korea

Maturation and Spawning of the Filefish Thamnaconus modestus in Coastal Waters of Korea

Maturation and Spawning of the Filefish Thamnaconus modestus in Coastal Waters of Korea

Life-history features and oceanography drive phylogeographic patterns of the chiton Acanthochitona cf. rubrolineata (Lischke, 1873) in the northwestern Pacific.

Chitons are a group of marine mollusks (class Polyplacophora) characterized by having eight articulating shell plates on their dorsal body surface. They represent suitable materials for studying the spatiotemporal processes that underlie population differentiation and speciation in ocean environments. Here we performed population genetic analyses on the northwestern Pacific chiton Acanthochitona cf. rubrolineata (Lischke, 1873) using two mitochondrial gene fragments (COI and 16S) from 180 individuals sampled from 11 populations among the coastal waters of Korea, Japan, and China. The phylogenetic network uncovered a reticulated relationship with several sub-haplogroups for all A. cf. rubrolineata haplotypes. SAMOVA analyses suggested the best grouping occurred at three groups (ΦCT = 0.151, P < 0.0001), which geographically corresponds to hydrographic discontinuity among the coastal regions of Korea, Japan, and China. The assumed limited dispersal ability of A. cf. rubrolineata, coupled with northeasterly flowing, trifurcate warm currents, might have contributed to the genetic differentiation among the three groups. Meanwhile, a high level of within-group genetic homogeneity was detected, indicating extensive coastal currents might facilitate gene flow among the populations within each group. Bayesian skyline plots demonstrated significant population expansion after the Last Glacial Period (110-25 thousand years ago) for all studied populations except the Japan group. Together these results suggest that the present-day phylogeographic patterns of A. cf. rubrolineata are strongly affected by the interplay of historical and/or contemporary oceanography and species-specific life-history features.

Major controlling factors for spatio-temporal variations in the macromolecular composition and primary production by phytoplankton in Garolim and Asan bays in the Yellow Sea

Little information on phytoplankton is currently available for Garolim and Asan bays, which are important spawning and nursery grounds for various commercial fish. The objectives of this study were to investigate the spatial and seasonal variations in the biochemical components (carbohydrates, proteins, and lipids) and primary production by phytoplankton and to determine the major environmental factors controlling the variations in Garolim and Asan bays. All major inorganic nutrients were seasonally available to phytoplankton although PO4 concentrations were relatively lower than those of other nutrients. The chlorophyll-a (chl-a) concentration measured in this study was within the range reported previously and the phytoplankton community was mostly dominated by micro- and nano-phytoplankton (approximately 80 %). Among the different biochemical compositions, carbohydrates were the most dominant throughout our observation period. As a nitrogen source for phytoplankton growth, ammonium was more important compared to nitrate in Garolim and Asan bays because of a significantly high uptake rate of the ammonium observed in this study. The overall mean areal daily carbon uptake rate (238.8 ± 393.3 mg C m−2 d−1) measured in this study is within the range in various bays and coastal waters in Korea. The concentrations of SiO2, NO2+NO3 and micro-sized chl-a were found to be major factors for the variation in the biochemical compositions of phytoplankton. By comparison, the nano-sized chl-a concentration, NH4 concentration and temperature were observed to be major factors in the variation in the carbon uptake rate of phytoplankton in Garolim and Asan bays during our observation period. Further studies on macromolecular compositions and primary production from different cell-sized phytoplankton are warranted for a better understanding their potential effects on marine ecosystems.

Spatial distribution of microplastic in the surface waters along the coast of Korea

We examined the spatial distribution and local characteristics of microplastics (0.33–5 mm) in surface water from six semi-enclosed bays and two coastal waters in Korea. Surveys were conducted in July from 2015 to 2017 using a Manta trawl. The mean abundance of total microplastics ranged from 1.12–4.74 particles/m3 among sites; the microplastics were mostly expanded polystyrene (EPS), paint particles, fragments and fibers. The mean microplastic abundance (2.85 particles/m3) in urban areas was about 1.5 times higher than in rural areas (1.86 particles/m3) (p < 0.05). EPS dominated at rural sites, while fragments, paint particles, and fibers were relatively more dominant in urban areas. The different types and quantities of microplastic particles indicated that the region-specific occurrence of microplastics is likely to be related to differences in human activities between urban and rural areas, even though fibers were distributed throughout the study area.