• Journal of Marine Bioscience and Biotechnology
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• v.10 no.2
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• pp.53-61
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• 2018

Sargassum fulvellum (gulfweed) is a widespread seaweed in the coastal areas of northeast Asia. In the present study, we identified the phenolic compounds present in aqueous and ethanolic extracts of S. fulvellum and evaluated their antioxidative properties and their abilities to block cell proliferation using in vitro assays: antioxidant activity was assessed by using a DPPH assay and superoxide anion scavenging activity, anti-tyrosinase activity, and anti-proliferative activity were assessed using MTT and lactate dehydrogenase [LDH] assays in vascular smooth muscle cells. The hot-water ($65^{\circ}C$) extract had a higher phenol content than the ethanolic extract. The hot-water extract showed a statistically significant increase in free radical scavenging activity and a greater ability to reduce proliferation of vascular smooth muscle cells stimulated with platelet-derived growth factor-BB. Taken together, hot-water extracts of S. fulvellum may be an important source of antioxidative and antiproliferative agents.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.435-441
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• 2011

The feeding habits of yellow goosefish Lophius litulon and John Dory Zeus faber were studied by analyzing the stomach contents of specimens collected in the South Sea of Korea. In total, 132 hauls were taken during six experimental trawl survey (Tamgu 1) cruises conducted on a seasonal basis (March 2005-October 2007). The main prey items of the two species were similar. Fishes and crustaceans were the most important prey, with neither species showing ontogenetic changes in preferred species. Specifically, Pennahia argentata was the preferred prey item of L. litulon, whereas Trichiurus lepturus and Engraulis japonicus were preferred by Z. faber. Larger Z. faber (>24 cm) preferred bigger prey such as T. lepturus and Larimichthys polyactis, while smaller Z. faber preferred E. japonicus and Acropoma japonicum.

• The Korean Journal of Malacology
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• v.27 no.1
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• pp.29-33
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• 2011

This study was conducted to investigate the recruitment pattern of sessile organisms on the artificial substrates of PVC in Jangmok Bay, Geoje Island, southern coast of Korea. Five PVC plates were submerged from March to October, 2007 at one month interval, and two plates were retrieved after one month. The dominant recruiters were a green algae, Entermorpha prolifera in March, Mytilus galloprovincialis in April, M. galloprovincialis and Styela plicata in May, S. plicata and Bugula sp. in June. During August, Balanus amphtrite and anthozoans were dominant recruiters, and a serpulid worm, Hydroides ezoensis in October. There was a clear specific recruiting period of sessile faunas depending on their reproduction cycles in a sheltered embayment like Jangmok Bay.

• Journal of Aquaculture
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• v.13 no.1
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• pp.9-12
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• 2000

A species of the parasitic copepods Phrixcephalus unbellatus (Lernaeide ; Cyclopoidea) from Branchiostegus japonicus is described and reported for the first time in Korea. The parasite was recovered from the eye of host. P. umbellatus was easily identified by the body shape extensive ramification of the antennal processes and numerous branches on the thoracic horns, The parasite inserted its head and the anterior portion of thorax up to the 4th segment in the eye ball of the host through a narrow hole which it usually burrowed near the upper margin of the cornea above the crystalline lens. Prevaklence of the parasite increased from 3.3% January to 11.9% in June.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.54-65
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• 2023

Effect of environmental factors on the seasonal variations of zooplankton communities was investigated in the semi-closed Yeoja Bay, Korea from February, April to August, and November 2021. Out of a total 49 species of zooplankton were collected with a predominant of neritic copepods (mainly Paracalanus orientalis, Acartia omorii, Acartia ohtsukai, Centropages abdominalis, Ditrichocorycaeus affinis, and Oithona sp.), accounting for 58.9% of the total abundance of zooplankton. The diversity indices indicated a relatively highest in July, suggesting that diversity is influenced by seasonal temperature, N. scintillans, and neritic copepods species. A cluster analysis with non-metric multidimensional scaling revealed four groups of zooplankton communities. The February sample clustered into Group A, having the lowest mean total abundance and species diversity of zooplankton, consisting mainly of N. scintillans located the whole region. Cluster Group B from the spring season (April to May) and contained the species diversity with some neritic copepods. Cluster Group C from the summer season (June to August) mainly comprised P. orientalis, A. ohtsukai, Oithona sp., and hydromedusae. Cluster Group D from the autumn season (November) mainly comprised P. orientalis, Temora discaudata. Redundancy analysis indicated that abundance is positively correlated with temperature, salinity, and pico chlorophyll-a concentrations. This study showed that planktonic larvae (such as branchyura larvae) and some copepods (including A. omorii, A. ohtsukai, C. sinicus, and C. abdominalis) were significantly vulnerable to zooplankton community of temperature, salinity, and pico chlorophyll-a concentrations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.4
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• pp.378-388
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• 2003

Seasonal variations in abundance and species composition of fish assemblage around Narodo were examined. Fish samples were monthly collected by a beam trawl from December 2000 to November 2001. A total of 62 fish species representing 37 families were collected. Of these, Thryssa kammalensis, T. hamiltoni, Chaeturichthys hexanema, Johnius grypotus, Leiognathus nuchalis, Cynoglossus robustus and Setipinna taty were dominant species comprising $82\%$ of the total number of individuals. Species diversity indices ranged from 1.2 to 2.2 showing the highest values from September to November 2001. The fish assemblage was divided into three different groups by cluster analysis of the fourteen dominant species. The main residence species were J. grypotus, L. nuchalis, C. hexanema, C. robustus, Setipinna tenuifilis, T. kammalensis and Ctenotrypauchen microcephalus. Of the temporal species T. hamiltoni, Liparis tanakai and Erisphex pottii were collected In spring, and Muraenesox cinereus and Trichiurus lepturus were in summer and autumn. Principal component analysis revealed that seasonal variation in the fish assemblage was attributed to the abundance of temporal species due to seasonal variation of environmental factors such as water temperature and ecological pattern (polagic/demersal) of fish species.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.72-77
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• 2016

We examined monthly changes in the rate of fishes by-caught by gape net with wings and their immature ratio in the coast of Yeosu and Jindo Island, Korea. A minus correlation between bycatch rate, the ratio of fishes except for anchovy, Engraulis japonicus, to all fishes collected by gape net with wings, and individuals of the collected anchovy was significantly observed, implying that as the anchovy catch decreased and the bycatch rate increased. Immature ratios by the dominant bycatch species during the study is the following; Leiognathus nuchalis was 72.7~99.0%, Sphyraena pinguis was 84.0%, Sardinella zunasi was 90.0%, others (Leptocephalus, Trichiurus lepturus, Ammodytes personatus, Sphyraena pinguis, Trachurus japonicas, Mugil cephalus and Erisphex pottii) were 100.0%. In order to decrease the high bycatch rates of immature fishes in spring and autumn, our study suggested increasing of codend mesh size and developing suitable bycatch reduction devices in a gape net with wings.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.4
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• pp.367-373
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• 2022

We analyzed work safety risk factors, which are likely to occur during fishing in gillnet fishing vessels using the written verdict of the Korea Maritime Safety Tribunal from 2016 to 2020, and considered work safety management. Of the total of 37 fatal accidents, three cases in the East Sea, six cases in the South Sea, and 28 cases in the West Sea were very frequent. The accident rate per vessel by sea area (%) was 0.08% in East Sea, 0.12% in South Sea, and 0.40% in the West Sea. Based on the East Sea, the number of fatal accidents was 1.6 times higher in the South Sea and 5.4 times higher in the West Sea. Six cases (16.2%) occurred during departure and preparation for fishing in the fishing process, and all other 31 cases (83.8%) occurred during fishing operation. In the order of accident types, 21 cases (56.8%) of being struck by object, eight cases (21.6%) of contact with machinery and six cases (16.2%) of falls from height were found to be fatal accidents in gillnet fishery. Human factors, such as fishers' carelessness and negligent safety management by captain accounted for 27 cases (73.0%) of the main cause, and 35 cases (94.6%) of the secondary cause. In addition to human factors such as fisher's carelessness and negligent safety management by captain, mechanical factors, environmental factors and management factors must be improved together to reduce human casualties. These results are expected to be utilized as basic data for reducing safety accidents during the work of fishers.

• The Korean Journal of Malacology
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• v.24 no.1
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• pp.59-66
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• 2008

The ark shell, Scapharca broughtonii were collected from the Jinhae bay in Kyungnam, Korea from April 2006 to October 2007. To assess how much they have tolerance against hypoxia under the compound condition of temperature and salinity, survivorship, oxygen consumption rate and external features of Scapharca broughtonii were measured, The 7 days-$LC_{50}$ of dissolved oxygen (DO) for Scapharca broughtonii at $15^{\circ}C$-ordinary sea water and $26{\pm}1$ psu was 1.98mg/L (confidence limit: 1,45-2.39 mg/L) and 2.63mg/L (confidence limit: 1.76-3.37mg/L) respectively. Whereas 3 days-$LC_{50}$ at $25^{\circ}C$-ordinary sea water was 3.89mg/L (confidence limit: 3.36-4.55 mg/L) and 4 days-$LC_{50}$ at $25^{\circ}C-26{\pm}1$ psu was 3.74mg/L (confidence limit: 3.19-4,43 mg/L). Oxygen consumption rate with each experimental group was decreased during the period exposed to hypoxia. To recovery, they were replaced to ordinary and oxygen consumption rate was increased a little, but all died, The color of the umbo of shell in Scapharca broughtonii was changed dark during hypoxia. These data will provide important fundamental information for examining the causes of mass mortality of shellfish in the summer.

• Journal of the Korean Society for Marine Environment & Energy
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• v.1 no.1
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• pp.56-65
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• 1998

An oil spill model, Green Sea Ranger(GSR) based on trajectory and fate modeling of spilt oil behavior is introduced. The various physical models on weathering processes are reviewed and those adopted by GSR are described. A database for currents, which is necessary for the real-time simulation of oil spill, is generated on the south sea of Korea. The real-time prediction of tidal currents in the South Sea of Korea is carried out. Four major constituents (M₂, S₂, K₁, O₁ tide) are employed in the prediction, and those angular speeds and phases are determined from the astronomical arguments. The harmonic constants of the constituents are computed by solving shallow-water tide equations. The GSR has user-freiendly GUI and flexible framework which makes it easy to expand the database for sea environments in Korean coastal waters. The GSR is validated by the simulation of O-Sung oil spill caused by a grounded oil tanker in coastal sea near Maemol-do. The simulated trajectory is compared with observed one and it is shown that the GSR gives reasonable estimation on spilt oil bahavior.