• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.689-693
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• 2016

Sargassum golden tides occurred in Shinan-gun and Jeju Island, Korea, between January and May 2015. In Shinangun, 5,180 tons of Sargassum were removed from 3,339 ha of coastline, while 20,000 tons were removed from Jeju Island. The huge floating masses of seaweed caused damage to fisheries in Shinan-gun including abalone sea cage, Pyropia and Saccharina farms off the southwest coast of Korea. Drifting Sargassum also washed ashore on Jeju Island. The species of Sargassum in these golden tides was identified as S. horneri (Turner) C. Agardh, based on morphology and molecular data, and it appears to have originated from the East China Sea. This is the first report on Sargassum golden tides causing damage to fisheries in Korea.

• Korean Journal of Plant Resources
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• v.35 no.6
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• pp.805-819
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• 2022

The taxonomic status and phylogenetic relationship of Opuntia monacantha Haw. f. jejuensis J. K. Kim ex Y. S. Yang (Jejubaiknyuncho), which is native to southern coast of Jeju Island, Korea was analyzed using DNA markers obtained from Korean Opuntia. Opuntia stricta Haw., O. humifusa Raf., and O. humifusa Raf. f. jeollaensis E. J. Kim and S. S. Whang, native or cultivated in Korea, have no stripes on the back of tepals and have a purple pulp, whereas O. monacantha f. jejuensis has purple stripes on the back of tepals and a greenish-yellow pulp color. Opuntia monacantha has purple stripes on both the front and back of its tepals, whereas stripes appear only on the back of tepals of O. monacantha f. jejuensis. Opuntia monacantha f. jejuensis was assigned to Elatae series in phylogenetic analysis and was found to be more closely related to O. monacantha subsp. arechavaletae (Speg.) Guiggi, compared with O. monacantha at a molecular level. Based on its phylogenetic and morphological differences from O. monacantha and O. monacantha subsp. arechavaletae, which are native or have been cultivated in Jeju areas, O. monacantha f. jejuensis was named as a new forma in this study.

• Korean Journal of Ichthyology
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• v.17 no.3
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• pp.217-220
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• 2005

Three specimens of leptocephalus larvae (33.4~35.2 mm in SL) were collected from the southern coast of Jeju Island, Korea, by an aquatic lamp on August 14, 2004. These larvae were identified as Elops hawaiensis because of their having a forked caudal fin, a smaller anal fin than dorsal fin, and anal-fin position posterior to dorsal fin.

• Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.2.1-2.5
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• 2017

This is the first report of Fowlerichthys scriptissimus (Lophiiformes, Antennariidae) from Korea. A single specimen (291.0 mm SL) was collected off the coast of Jejudo Island by gill net on 28 March 2012 and identified with morphological and molecular approaches. The specimen is characterized by having all five pelvic fin rays bifurcate and possessing 20 vertebrae, 13 pectoral-fin rays, and a basidorsal ocellus on the side of the body. This species is distinguishable from other Korean taxa by the number of pectoral fin rays, the bifurcate form of the pelvic rays, and the vertebral count. We add this species to the Korean fish fauna and suggest new Korean names, "Byeol-ssin-beng-i-sok" and "Byeol-ssin-beng-i" for the genus and species, respectively.

• Fisheries and Aquatic Sciences
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• v.10 no.2
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• pp.68-73
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• 2007

Based on four juvenile specimens of Lutjanus collected from the southern coast of Jeju Island, three species, L. argentimaculatus, L. fulviflamma, and L. quinquelineatus, are described as the first record from Korea. The first species is easily differentiated from other lutjanid juveniles by distinct coloring of the dorsal, pelvic, and anal fins as well as two blue lines below the eye; the second species is characterized by having six yellowish brown stripes below the lateral line and a black spot on the side; the third species is identified by five longitudinal blue stripes and a black spot on the side when fresh. The new Korean names "Bul-geun-tung-dom," "Yuk-seon-jeomtung-dom," and "O-seon-tung-dom" are proposed for L. argentimaculatus, L. fulviflamma, and L. quinquelineatus, respectively.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.117-123
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• 2021

Post-disturbance recovery pattern of subtidal soft corals-macroalgae mixed community and the role of water depth were investigated. The experiment was conducted in a subtidal rock wall of Munseom, Jeju Island, Korea for 2.5 years. Artificial disturbance was done at established treatment plots at depths of 10, 15 and 20 m and were then compared with undisturbed control plots. After disturbance, recovery of soft corals was very slow, whereas macroalgae quickly occupied the plots and reached a similar level as the control in 6 months, and this pattern was consistent at all water depths. This unbalanced speed of recovery caused higher macroalgae establishment than soft corals in treatment compared to control plots, indicating a possible phase shift in the community structure. This study provides an important implication for the necessity of monitoring the influence of disturbance at a larger scale, from a conservation perspective of soft corals in Jeju coast.

• Journal of Life Science
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• v.24 no.8
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• pp.880-886
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• 2014

In this study, we isolate and identify bacteria from seawater collected from Jeju coast, to evaluate the antimicrobial activity against the fish pathogenic bacteria. 14 bacterial strains were isolated and identified using physiological, biochemical and molecular tools. Antibacterial activity of all the 14 isolates were screened against four major fish pathogens namely, two Gram-positive: Streptococcus iniae, Streptococcus parauberis and two Gram-negative: Vibrio anguillarum, Edwardsiella tarda. Results revealed that among the 14 isolates, MK-11 was found to have antibacterial activity against S. iniae, S. parauberis, V. anguillarum Particularly, S. iniae was susceptibility with the MIC value of $250{\mu}g/ml$. The biochemical and physio-chemical results reveal that MK-11 had the sugar-alcohol disassemble ability of the D-sorbitol and D-mannitol. Also the utilization of the yeast extract, sorbitol and di-potassium phosphate were noted to be high. The optimum culture condition such as pH and temperature was recorded as pH 6.0, $25^{\circ}C$ and along with 1% NaCl which differs from the previous reports particularly in nutrient resolutions. As results of the analysis of 16S rDNA sequences, MK-11 show the high similarity with Paenibacillus polymyxa, P. jamilae, P. brasilensis 99.78%, 99.43%, 99.39%, repectively. Hence, in the present study, the isolated Paemibacillus sp. MK-11 from Jeju seawater possesses the antibacterial activity against fish pathogens and it could be used as a new antibiotic agents against the gram positive fish pathogens.

• Journal of Life Science
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• v.32 no.9
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• pp.721-728
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• 2022

This study investigated the diversity of intestinal microbial communities isolated from the intestine of topshell (Turbo cornutus) from the coast of Jeju Island (Beobhwan, Seogwipo city). Pure cultivation using the standard marine agar (MA) medium showed the most significant number of clusters. Aerobic and anaerobic culture allowed isolation of strains of 1.8×10⁵ CFU·g^-1 and 0.4×10 CFU·g^-1 on average, respectively. The microbial population in the topshell intestine was classified into 4 phyla, 12 families, 26 genera, and 67 species. The microbes in the topshell intestine were detected by homology with 93~100% with standard strains. The microbes in the topshell intestine consisted of Proteobacteria 39%, Firmicutes 34%, Actinobacteria 21%, and Bacteroidets 6%. The identified families were Alteromonadaceae (1), Shewanellaceae (4), Vibrionaceae (12), Phyllobacteriaeceae (1), Rhodobacteraceae (8), Bacillaceae (21), Paenibacillaceae (2), Cellulomonadaceae (1), Mycobacteriaceae (6), Nocardiaceae (4), Streptomycetaceae (3) and Flavobacteriaceae (4). Bacillus sp. and Vibrio sp. accounted for the greatest portion of the separated strains. Among the isolated microorganisms, some strains had probiotic functions.

• Journal of Life Science
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• v.18 no.3
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• pp.395-402
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• 2008

Level of microbial contamination was examined in four fish farms of Jeju east coast for sanitary indication of bacterial contamination such as heterotrophic bacteria, Escherichia coli O157:H7, Salmonella spp., Vibrio parahaemolyticus, Staphylococcus aureus, Bacillus cereus and total coliforms. The samples were collected and investigated from June to October in 2007. Bacterial species of S. aureus, B. cereus and Salmonella spp. were frequently detected from the seawater of above fish farms. Salmonella spp., S. aureus, B. cereus were detected in the range of $0{\sim}4.3{\times}l0^3,\;0{\sim}2.7{\times}l0^4,\;0{\sim}7.6{\times}l0^3$ CFU/ml, respectively, from the fish feed used in all four selected farms. Additionally, Salmonella spp., S. aureus, B. cereus were detected in oliver flounder (Paralichthys olivaceus) of these farms, however total coliforms and E. coli O157:H7 were not detected during our experimental period. For the production of microbiologically safe and healthy oliver flounder, proper quality control of feed, sanitation programs, and continuous monitoring of microorganism are essential practices, which required to include in the farm management system.

• Journal of Navigation and Port Research
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• v.29 no.4
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• pp.327-333
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• 2005

Sea level (MSL, MHWL, or MLWL) change has been main concern to scientists and engineers and it can be primarily due to both change of climate and vertical movement of land. This paper reports the intensive analysis of the sea level changes and broad discussion of the future at the southwestern coast of Korean peninsula. Regression analysis was conducted to investigate general tendency and periodicity of the sea levels at the six different study sites such as Gunsan-I(inner port), Gunsan-O(outer port), Mokpo, Yeosu, Heuksan and Jeju and the results were compared with global values. Besides the changes of sea levels due to global warming, the influence of the man-made structure such as seadike and seawall was attempted to quantify using the minimization of the Root Mean Square(RMS) error. The results show that it is a general tendency that the values of mean sea level rise at the southwestern coast of Korean Peninsula, especially at Gunsan-I and Jeju, are somewhat larger compared to global average values. There is also some evidence that tidal amplifications are found just after construction of man-made structure at Gunsan-I and Mokpo. However, both sites show different mechanism in relation to tidal choking, tidal flat and river discharge. The impact due to construction of man-made structure is considerably larger at Mokpo site, while the impacts due to man-made structure and the effect of sea level rise are relatively identical at Gunsan-I site. This study is expected to provide some intuition to future design.