• ALGAE
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• v.32 no.4
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• pp.309-324
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• 2017

Recently, the heterotrophic nanoflagellate Katablepharis japonica has been reported to feed on diverse red-tide species and contribute to the decline of red tides. However, if there are effective predators feeding on K. japonica, its effect on red tide dynamics may be reduced. To investigate potential effective protist predators of K. japonica, feeding by the engulfment-feeding heterotrophic dinoflagellates (HTDs) Oxyrrhis marina, Gyrodinium dominans, Gyrodinium moestrupii, Polykrikos kofoidii, and Noctiluca scintillans, the peduncle-feeding HTDs Luciella masanensis and Pfiesteria piscicida, the pallium-feeding HTD Oblea rotunda, and the naked ciliates Strombidium sp. (approximately $20{\mu}m$ in cell length), Pelagostrobilidium sp., and Miamiensis sp. on K. japonica was explored. We found that none of these heterotrophic protists fed on actively swimming cells of K. japonica. However, O. marina, G. dominans, L. masanensis, and P. piscicida were able to feed on heat-killed K. japonica. Thus, actively swimming behavior of K. japonica may affect feeding by these heterotrophic protists on K. japonica. To the contrary, K. japonica was able to feed on O. marina, P. kofoidii, O. rotunda, Miamiensis sp., Pelagostrobilidium sp., and Strombidium sp. However, the specific growth rates of O. marina did not differ significantly among nine different K. japonica concentrations. Thus, K. japonica may not affect growth of O. marina. Our findings suggest that the effect of predation by heterotrophic protists on K. japonica might be negligible, and thus, the effect of grazing by K. japonica on populations of red-tide species may not be reduced by mortality due to predation by protists.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.2
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• pp.173-184
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• 2021

In this study, internationally widely utilized bioeconomic models were used to make a comparison and analyze the effectiveness of red snow crab fisheries management measures. As a specific effect analysis, biological and economic effects of both total allowable catch (TAC) and effort reduction management measures were analyzed simultaneously. Model results showed that the red snow crab biomass would be decreased from 106,000 tons to 73,076 tons after ten years when the TAC is set to and maintained at the current level of 26,000 tons. The amount of biomass would be increased to 125,316 tons when the level of TAC is set to 22,000 tons. In cases of reduced fishing efforts, a 30% decrease from the current level would result in greater biomass and NPV would be also estimated at the highest level. In addition, a sensitivity analysis by market price was conducted to analyze the minimum TAC level of the red snow crab offshore pot fishery. Results showed that the minimum TAC level would be 8,210 tons when the market price increased by 30% and it would be also 15,247 tons when the market price decreased by 30%. Furthermore, results of the sensitivity analysis by fishing cost showed that the minimum TAC level was analyzed to be 13,857 tons when the fishing cost increased by 30% from the current level.

• Natural Product Sciences
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• v.6 no.2
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• pp.61-65
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• 2000

The ethanolic extracts of marine green, brown and red algae collected from Karachi coasts of Arabian Sea afforded a new enol-derivative of N-acylsphingosine named as coelarthenol (1) from Coelarthrum muelleri, two new glucose-derivatives named: botryenal (2) and botryenol (3) from Botryocladia leptopoda, ${\alpha}-tocopherol$ quinone (4) from Codium iyengarii, ${\beta}-sitosterol$ and hexadecanoic acid from Stokeyia indica. The known constituents (4, ${\beta}-sitosterol$ & hexadecanoic acid) have not been reported so far from their corresponding sources and the structures were determined through spectroscopic methods, whereas, the structures of new constituents (1-3) were elucidated with the aid of selective HMBC experiments. The phytotoxicity of 4 was also monitored.

• Korean Journal of Environmental Biology
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• v.28 no.1
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• pp.20-29
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• 2010

Cochlodinium polykrikoides has occurs regularly during the summer in the South Sea of Korea. To investigate photosynthetic pigments concerned with phytoplankton community structure as bloom of Cochlodinium polykrikoides, the experiment was sampled at 20 stations three times between July and September 2002 in the Southern Sea of Korea. The distribution of peridinin, the biomarker of dinoflagellate, was higher at the blooming time than it was before and it disappeared after bloom. The correlative coefficients between Chl. a and peridinin at the blooming time and out of bloom were 0.9253 and 0.1613, respectively. This result indicated that the bloom was caused by dinoflagellate. The correlative coefficients between Chl. a and fucoxanthin were 0.3282 and 0.9759, respectively, and the correlative coefficients showed the succession from dinoflagellate to diatom. This result means that the bloom of Cochlodinium polykrikoides can be detected by Chl. a information from satellite remote sensing. Therefore, if the algorithm to detect peridinin in addition to Chl. a were to be developed, dinoflagellate red tide could be monitored more effectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.973-977
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• 2014

We studied distribution of seabirds using strip transect counts from May $2^{nd}$ to $30^{th}$, 2011. we observed 322 individuals from nine seabird species. Black-tailed gulls (Larus crassirostris, 48.4%) were numerically dominant. Ancient murrelets (Synthliboramphus antiques, 18.6%), Vega gulls (Larus vegae, 17.7%), red-throated divers (Gavia stellata, 4.7%), Pacific divers (Gavia pacifica, 4.3%), streaked shearwaters (Calonectris leucomelas, 1.9%), and common terns (Sterna hirundo, 1.6%), were also frequently observed. The overall seabird density was 0.55 birds $km^{-2}$, lower that of the East Sea.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.1
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• pp.15-22
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• 2008

For the improvement of letterpress printing paper quality, special fibers obtained from the sea were used by mixing with wood fibers. The sizes of the special fibers, which were from red algae in the sea, were 0.5-1 mm in length, and 3-7 ${\mu}m$ in width, respectively, and the fibers were supplied by Pegasus Research Inc. for the study. From the study, it was found that 10% addition of algae fibers greatly improved paper surface strength and internal bonding strength. The compressibility was estimated by utilizing 'Print-surf method' at high clamping pressure and with hard backing. Again, 10% addition of algae fibers greatly improved the compressibility of the paper. These results were expected that algae and wood fibers were distributed evenly through the sheet, and integrated one another to leave no empty space inside the paper.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.637-644
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• 2014

Two Chionoecetes crabs, C. opilio and C. japonicus are primary targets of trap fisheries in the East Sea. To promote the sustainable management of these species, we investigated their reproductive biology and spatial distribution based on samples collected in standardized traps in the coastal waters of eastern Korea from September 2007 to August 2008. The estimated spawning season of C. opilio was March-April, whereas that of C. japonicus continued year-round. The estimated molting period of both species was September-October. Fecundity of C. opilio was proportional to female, size, ranging from 44,791 to 151,538 eggs, and the estimated body size at 50% sexual maturity was 63.9 mm carapace width. Egg bearing female C. opilio were mostly collected depths of 200-300 m, particularly off Hupo and Chuksan, suggesting that these areas are their major spawning grounds. In contrast, female C. japonicus were mostly collected at depths of 400-600 m, peaking at 600 m. The species-specific catch rate was higher for C. opilio above 400 m, similar at ca. 450 m, and higher for C. japonicus below 500 m. These vertical differences indicate apparent spatial segregation of the species, suggesting that spatially-explicit fisheries management plans may be necessary for mitigating conflicts between the respective crab fisheries and maintaining these crabs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.322-328
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• 2009

Three-hundred and sixteen Escherichia coli strains from seawater, and a variety of farmed fishes, including oliver flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagrus major) and sea bass (Lateolabrax japonicus) between May to October in 2004, were tested by agar dilution method to determine their susceptibility patterns to 17 antimicrobial agents. Overall, 92.1% of Escherichia coli isolates from samples showed antimicrobial resistance to at least one antimicrobial agent and the multiple resistance was seen in 173 isolates (54.7%). The resistance of E. coli isolates to tetracycline (74.1%) was highest, followed by cephalothin (69.9%), doxycycline (66.5%), streptomycin (47.2%), ampicillin (46.2%), cefazolin (31.6%), enrofloxacin (31.0%). norfloxacin (28.2%). The most frequent resistance pattern was TE-D-CF-CIP-ENO-NOR-AM-S-C-SXT-AmC-CZ (14.7%), followed by CF (6.2%), TE (5.1%), TE-CF (4.5%) in 177 isolates from fishes and TE-D-CF (7.2%) followed by TE-D-CF-S (5.8%), CF and TE-D-S (3.6%) in 139 isolates from seawater.

• Ocean and Polar Research
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• v.29 no.4
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• pp.327-337
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• 2007

Plankton communities have close relationships with environmental changes in water columns. Thus, the use of plankton as a biological tool for assessing the marine ecosystem health may be effective. Major issue regarding coastal pollution has been usually recognized as phytoplankton blooms or red tides caused by the eutrophication, an increase in concentration of inorganic nutrients such as nitrogen and phosphorus. However, in order to understand the effects of the overall pollution on marine ecosystem, the organic pollutants as well as the inorganic nutrients should be also considered. For understanding the effects of the organic pollution, among the planktonic organisms, heterotrophic bacteria, heterotrophic flagellates and ciliates should be investigated. Generally, there are three approaches for assessing the marine ecosystem health using the plankton taxa or plankton communities. The first one is a community-based approach such as diversity index and chlorophyll a concentration which are common in analysis of the plankton communities. The second is an indiviual-based approach which is to monitor the pollution indicative species. This approach needs one's ability to identify the plankton to species level. The last approach is a bioassay of toxicity, which can be applied to the plankton. A pilot study in Masan Bay was conducted to assess the effects of the inorganic and organic pollution. In this article, a new approach using plankton communities was tentatively presented as a biological tool for assessing the ecosystem health of Masan Bay.

• Textile Coloration and Finishing
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• v.34 no.3
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• pp.135-145
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• 2022

In this study, the dyeability of 0.06-denier-per-filament (dpf) ultrafine sea-island-type nylon knitted fabric was investigated and compared with that of 1.0-dpf general nylon with respect to four types of dyes. In particular, leveling, milling, half-milling, and metal-complex dyes were compared at concentrations of 0.5%, 1.0%, 2.0%, 4.0%, and 8.0% on-weight-fabric (o.w.f). In each case, staining was performed at 100 ℃. The dyeabilities of the materials were compared in terms of the depth of color as defined by the ratio of the absorption coefficient (K) to the scattering coefficient (S). Results indicated generally low K/S values for both the 0.06-dpf ultrafine sea-island-type nylon and 1.0-dpf general nylon. In terms of the dye type, the milling and half-milling dyes exhibited K/S values of ≥20 for all colors of yellow, red, and blue for the 0.06-dpf ultrafine yarn sea-island-type nylon, which were superior to those of the other dye types. Hence, the milling and half-milling dyes are considered more suitable than the other dyes. Further, a comparison of dye fastness and compatibility revealed that the half-milling dye was the most suitable dye for the 0.06-dpf ultrafine sea-island-type nylon.