• Title/Summary/Keyword: Marine science

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Diet Composition of Tanaka's snailfish, Liparis tanakae in the Yellow Sea, Korea (한국 서해에 출현하는 꼼치(Liparis tanakae)의 위내용물 조성)

  • Suyeon Jin;Da Yeon Kang;Gi Chang Seong;Do-Gyun Kim;Ho Seung Kim;Hyeon Ji Kim;Jeong Hoon Lee;Gun Wook Baeck
    • Korean Journal of Ichthyology
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    • v.35 no.4
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    • pp.354-360
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    • 2023
  • The diet composition of Tanaka's snailfish, Liparis tanakae were collected by bottom trawl net in the Yellow Sea of Korea during 2022 (April, August, October, and November). The size of the specimens ranged from 3.8 to 52.2 cm in total length. L. tanakae were primary consumed caridea shrimps (Crangon hakodatei, Eualus spathulirostris, etc.) and specialist feeder mainly consumed caridea shirmps (C. hakodatei). The L. tanakae's trophic level is 3.63. Caridea shrimps were the primary prey items for all size groups (<20 cm, 20~30 cm, 30~40 cm, ≥40 cm). The proportion of E. spathulirostris has increased as the body size of L. tanakae increased, whereas the proportion of C. hakodatei decreased gradually. As the body size of L. tanakae increased the mean weight of prey per stomach (mW/ST) tended to increase significantly (One-way ANOVA, P<0.05). The caridea shrimps were the primary prey items throught all seasons. In summer, the main prey items were the C. hakodatei, however, in autumn, the proportion of C. hakodatei decreased while the proportion of E. spathulirostris increased.

Antioxidant Activity of a Chitin-degrading Bacterium Bacillus idriensis (CGH18) (키틴분해 박테리아 Bacillus idriensis (CGH18)의 항산화 활성)

  • Jung, Myoung Eun;Hong, Joo Wan;Lee, Jeong-Im;Kwak, Myoung Kuk;Kim, Hojun;Sohn, Jae Hak;Song, Young-Sun;Oh, Kwang-Suk;Seo, Youngwan
    • KSBB Journal
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    • v.28 no.4
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    • pp.217-224
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    • 2013
  • A bacterium CGH18 exhibiting antioxidizing and chitin-degrading activities in the colloidal chitin culture medium was isolated from salt-fermented crab. This strain was identified as Bacillus idriensis based on 16S rDNA sequence homology search. Its crude extract was partitioned between n-BuOH and $H_2O$. The organic layer was further partitioned between $CH_2$ $Cl_2$ and $H_2O$. Antioxidant activities of crude extract and its solvent fractions were evaluated using five different bioassay methods, including the degree of occurrence of intracellular reactive oxygen species (ROS), peroxynitrite scavenging (ONOO), and oxidative damage of genomic DNA. All fractions exhibited significant antioxidant activity in bioassay systems used.

Diet composition and trophic level of jack mackerel, Trachurus japonicus in the South Sea of Korea (한국 남해에 출현하는 전갱이(Trachurus japonicus)의 위내용물 조성과 영양단계)

  • KIM, Do-Gyun;SEONG, Gi Chang;JIN, Suyeon;SOH, Ho Young;BAECK, Gun Wook
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.57 no.2
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    • pp.117-126
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    • 2021
  • Diet composition and trophic level of Trachurus japonicus were studied using 417 specimens collected by trawls, set nets and purse seine fisheries from March 2019 to February 2020 in the South Sea of Korea. The size of T. Japonicus ranged from 7.0 to 49.8 cm in total length. T. japonicus were a carnivore that fed mainly on euphausiids and pisces. In eddition, T. japonicus fed on small quantities of cephalopods, crabs etc. T. japonicus showed ontogenetic changes in feeding habits. The proportion of euphausiids decreased inversely proportional to body size whereas the consumption of pisces gradually increased. As body size of T. japonicus increased the mean number of prey per stomach and the mean weight of prey per stomach tended to increase, but the mean number of prey per stomach was not significantly different. As a result of the feeding strategy analysis, T. japonicus were specialized feeders with pisces and euphausiids as their dominant prey. The trophic level ranged between 3.57 ± 0.54 and 3.91 ± 0.65, and increased asymptotically with size of specimens. The average trophic level of the T. japonicus was 3.79 ± 0.61.

Physiological Characteristics of Olive Flounder (Paralichthys olivaceus) and Korean Rockfish (Sebastes schlegelii) According to the Concentration of Suspended Load (부유사 농도에 따른 넙치와 조피볼락의 생리학적 특성)

  • Ha-Jeong Son;Kwang-Min Choi;Gyoungsik Kang;Won-Sik Woo;Kyung-Ho Kim;Min Yong Sohn;Min-Soo Joo;Chan-Il Park
    • Korean Journal of Ichthyology
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    • v.34 no.4
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    • pp.253-261
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    • 2022
  • After exposing Olive flounder and Korean rockfish to the concentration ranges of control (0 mg/L), 100 mg/L, 250 mg/L, 500 mg/L, and 1,000 mg/L, to investigate the physiological properties of suspended load on fish AST/GOT, ALT/GPT, ALP and cortisol were analyzed. As a result of the analysis, the AST/GOT, ALT/GPT, ALP and cortisol values were higher in the suspended load concentration section than in the control group. After artificial infection with S. parauberis for Olive flounder and V. harveyi for Korean rockfish exposed to suspended load, the survival rate was higher in the control group than in the suspended load concentration section. These results are related to the previously study results of suspended load that adversely affect fish, suggesting that suspended load affects the health of fish.

Comparison of Stomach Contents of Yellow Goosefish Lophius litulon, in the South Sea and Yellow Sea, Korea (한국 남해와 서해에서 출현하는 황아귀(Lophius litulon)의 위내용물 조성 비교)

  • Kim, Do-Gyun;Jeong, Jae Mook;Lee, Seung-Jong;Kang, Sukyung;Seong, Gi Chang;Kang, Da Yeon;Jin, Suyeon;Baeck, Gun Wook
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.55 no.5
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    • pp.714-720
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    • 2022
  • A dietary comparison of yellow goosefish Lophius litulon in the South Sea and Yellow Sea was performed by analyzing stomach contents. Using a bottom trawl net from fisheries resources survey vessels of the National Institute of Fisheries Science, 326 individuals were collected from the South Sea and 166 individuals were collected from the Yellow Sea. The total length range of L. litulon was 5.3-68.4 cm for individuals collected from the South Sea and 7.5-55.1 cm for individuals collected from the Yellow Sea. Based on the index of relative importance and the variation in stomach contents by fish size, L. litulon was found to be a piscevore and a spatiotemporally opportunistic feeder fish that fed mainly on pisces. There were differences in the composition of the stomach contents by season, location, and the interaction between the season and the location. Thus, the diet of L. litulon is affected by the prey abundance and prey spectrum of the habitat.

Antimicrobial effect of chitosan oligosaccharides, prepared under ultrafiltration membrane bioreactor, against pathogenic bacteria causing flounder fish diseases in aquacultural farm

  • Heo, Moon-Soo;Jeon, You-Jin;Lee, Ki-Wan;Song, Choon-Bok;Lee, Jehee;Yeo, In-Kyo;Yang, Byung-Gyoo;Kim, Se-Kwon
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • 2001.10a
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    • pp.145-146
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    • 2001
  • Despite a variety of development in fish farming during the last decades, fish diseases by bacteria, virus, and parasites are still major problems in aquaculture. Aquaculture of Hounder fish is widely performed around Korea as well as Jeju island, due to relatively stable seed production, short farming period, and a higher value in market. However, intensive feeding and environmental pollution in aquacutural farm act as a great limiting factor in economic aspect. (omitted)

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Antimicrobial effect of chitosan oligosaccharides, prepared under ultrafiltration membrane bioreactor, against Vibrio spp. causing fish diseases

  • Lee, Jehee;Jeon, You-Jin;Heo, Moon-Soo;Lee, Ki-Wan;Song, Choon-Bok;Yeo, In-Kyo;Yang, Byung-Gyoo;Kim, Se-Kwon
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • 2001.10a
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    • pp.151-152
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    • 2001
  • Chitin, a polymer of N-acetylglucosamine ($\beta$-1,4 linked 2-acetamido-D-glucose), is a cellulose-like biopolymer present richly in the exoskeleton of crustaceans and in cell walls of fungi, insects and yeast. Chitosan is derived from chitin by deacetylation, to different degrees, in the presence of alkali. [l]. Recent studies for chitin and chitosan have been concentrated in bioactivities such as antitumor activity, immuno-enhancing effects, enhancing protective effects against infection with some pathogens in mice, and antimicrobial activeity [2]. (omitted)

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