• Ocean and Polar Research
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• 제26권1호
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• pp.11-22
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• 2004

Benthic pollution assessment based on macrobenthic community structure with environmental variables was carried out at twelve stations during two periods on a presumed pollution gradient in Gamak Bay. Univariate and multivariate methods were applied to investigate structural changes in the benthic communities. A clear gradient of pollution effects on the macrobenthic community was observed from the interior to the exterior of the bay. The community on the northwestern basin was severely disturbed due to a low level of hydrodynamics and a large amount of pollutant input from nearby cities. Exterior regions on the southern basin appeared to have the best benthic environmental characteristics among all stations according to most methods of analysis. Central ridge regions and two stations around the islets in the mouth of the bay exhibited intermediate levels of perturbation when compared to the more disturbed interior and undisturbed exterior regions. Pollution effects on the communities were attenuated at the southern area of the central ridge during spring compared to those of summer, where aquacultural farming was densely distributed. The environmental variables primarily correlated to the macrobenthic community structure were total organic carbon (C), organochlorine pesticides (OCPs), and tributyltins (TBTs), contents found on the surface sediment, as anthropogenic variables indicating organic materials.

• 수산해양교육연구
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• 제6권2호
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• pp.93-116
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• 1994

This paper aims to explain the direction of a long-range policy for the development of fisheries industry and fishing villages in Korea after the Conclusion of the Uruguay Round Negotiations. When the Uruguay Round Negotiations were concluded last year, the government soon set up the Committee of Farming and Fishing Village Development under the direct control of the President and launched on the development of agriculture and fisheries policy to provide for the post-Uruguay Round. The Committee drew up an all-round policy report, "The Problem and Direction of Agriculture Policy Reform" as a result of the six-month activity of this committee from February through July, 1994 in which the author participated, and presented it to the President. The author rearranged the problems of a long-range policy related to fisheries industry and fishing villages apart from this report, and drew up another report under the title, "Fisheries Policy in Korea after the Conclusion of the Uruguay Round Negotiations : Its Problem and Direction," which was reported at the year 1994 autumn symposium of the Korean Pedagogic Society of Fisheries and Marine Sciences.

• Fisheries and Aquatic Sciences
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• 제25권1호
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• pp.1-11
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• 2022

Catfish is one of the most important freshwater fish farming commodities in Indonesia. Higher catfish production can be achieved by cultivating transgenic catfish carrying the growth hormone (GH) gene of African catfish (Clarias gariepinus GH, CgGH). This research focuses on analysis of the presence of the CgGH gene in transgenic G₁, G₂, and G₃ mutiara catfish broodstock, as an indication of stable CgGH inheritance. CgGH gene was isolated using the RNeasy mini kit and RT-PCR. RT-PCR revealed amplicons measuring approximately 600 bp in transgenic G₀, G₁, G₂, and G₃ mutiara catfish. The CgGH consensus sequence similarities ranged from 93.76% to 97.06%, with four functional domain sites (somatotropin-1, somatotropin-2, four α-helix, N-glycosylation, four cysteine residues) of fish GH proteins. The functional domains of fish GH proteins are conserved in G₁, G₂, and G₃ and indicate stable exogenous GH inheritance to produce transgenic catfish strains in each generation.

• ALGAE
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• 제39권1호
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• pp.31-41
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• 2024

Acadian marine plant extract powder (AMPEP) and Kelpak are commercial biostimulants derived from brown algae Ascophyllum nodosum. This study was to determine if AMPEP and Kelpak can induce thermal resistance in Pyropia yezoensis. P. yezoensis blades were exposed to different concentrations (control: 0, low: 0.001, high: 1 ppm) of AMPEP and Kelpak at 10℃ for 6 and 7 days, respectively. Those blades were then cultivated in von Stosch enriched seawater medium at different temperatures (10, 15, 20, and 25℃) with 12 : 12 L : D photoperiod and 100 µmol m^-2 s^-1 of photosynthetically active radiation for additional 15 days. Results showed that P. yezoensisreproduced archeospores at 20 and 25℃ at all biostimulant conditions within 15 days. At lower temperatures (10 and 15℃), only AMPEP-treated P. yezoensis reproduced archeospores. P. yezoensis exposed to 1 ppm Kelpak exhibited higher phycoerythrin and phycocyanin contents than control and 0.001 ppm conditions at 15℃. AMPEP-treated conditions showed higher phycoerythrin and phycocyanin contents than control at 10℃. These results suggest that AMPEP and Kelpak may not enhance the thermal resistance of P. yezoensis. However, AMPEP stimulated archeospores release at lower temperatures. The treatment of AMPEP and Kelpak also increased the pigment contents in P. yezoensis. These results suggest that the use of seaweed-derived biostimulants can provide some economic benefits in P. yezoensis aquaculture. The enhancement of archeospores formation by AMPEP at lower temperature may also increase the productivity since Pyropia farming relies on the accumulation of secondary seedings via asexual reproduction.

• 수산해양기술연구
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• 제56권3호
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• pp.223-229
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• 2020

We analyzed the cutting mechanism of laver harvesting machine in the sea area near Gooam Port in Goheung, Jeollanam-do, and investigated the change and efficiency of laver collecting operation in the working ship. The laver working ship slides uniformly from the bow to the upper part of the laver collecting machine on the deck and cuts the wet laver attached to the bottom of the net at the blade of the havesting machine. The laver farming net, which was loaded with laver turrets on the deck by gravity and collected primitives, consisted of a ship structure that led to the stern side and into the sea. The working ship operation is in harvesting process while driving in a S-shape that is separated by one space to efficiently collect the laver net. During laver working ship operation, the speed was 0.51 m/s in the access stage, 0.56 m/s in the havesting stage, and 0.52 m/s in the exit stage. Considering the cutting edge life and production efficiency of the laver harvesting machine, it is appropriate to harvest 1.15 to 1.26 kg/rpm by operating at a rotational speed of about 700 to 800 rpm rather than forcibly harvesting the product at high speed. On the deck of the working ship, 959.7 kg of starboard and 1048.7 kg of center were 964.7 kg of port side. Based on the starboard, 9.3% of the central part and 0.5% of the port side appeared. The reason for this was due to the difference in harvest time according to the turning direction of the working ship.

• 한국수산과학회지
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• 제33권6호
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• pp.508-513
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• 2000

알카리 안정화방법에 의거하여 양식장 퇴적물을 농업용 유기질 비료로 사용하기 위한 기초연구로서 제조과정에 따른 비료의 유효성분 및 중금속농도를 분석하고, 비료의 유해성 여부를 평가하였다. 퇴적물과 축산분뇨 혼합율 및 첨가제의 양을 달리하여 비료를 제조한 결과 생석회 $30{\%}$ 첨가시 건중량비 1 : 4 이었을 때가 최적의 반응조건 이었다. 또한, 알카리 안정화제로서 수산화 마그네슘도 영양분의 보강제 측면에서 사용될 수 있음을 보여 주었다. 제조된 퇴적물 조비료는 질소 및 칼륨 함량을 기준으로 할 때 중급 내지 고급 비료로 평가되었으며, 칼슘과 마그네슘의 함량은 고급 비료에 속하였다. 이상의 결과들은 알카리 안정화 방법으로 양식장 퇴적물을 유기질 비료로 전환 생산할 수 있음을 제시한다. 또한 알카리 안정화에 의해 제조된 비료내의 중금속 및 병원성균에 의한 유해성은 없는 것으로 나타났다.

• 한국수산과학회지
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• 제24권1호
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• pp.39-51
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• 1991

굴 양식장 수역에 있어서 식물플랑크톤에 의한 기초생산력을 파악하기 위해 한산-거제만과 가막 양만을 대상으로 1년간 $^{14}C$ 법으로써 조사하였다. 한산-거제만의 경우, 일간기초생산력은 평균 $0.52gC/m^2/day(0.22{\~}1.02gC/m^2/day)$로 여름에 비교적 높고 겨울에 낮았다. 연간기초생산력은 $189gC/m^2/yr$로 추정되었다. 엽록소 a양은 평균 $1.70mg/m^3$로서 비교적 여름에 높았다. 가막양만의 경우, 일간기초생산력은 평균 $0.91gC/m^2/day\;(0.11{\~}3.61gC/m^2/day)$로 여름에 최고치 그리고 가을에 최저치를 보였다. 연간기초생산력은 $334gC/m^2/yr$로 추정되었다. 엽록소 a 양은 평균 $2.34mg/m^3$로서 여름에 최고치를 보였으며, 겨울에도 비 교적 높았다. 두 굴 양식장의 수면적을 고려하면, 식물플랑크톤에 의해 생산되는 탄소량은 한산-거제만이 9,450ton이고 가막양만이 37,000ton이었다. 본 조사수역의 기초생산력은 봄의 생산력 증가와 함께 여름에 높은 생산력을 보였다.

• 한국환경과학회지
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• 제23권10호
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• pp.1703-1718
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• 2014

An eco-friendly integrated multi-trophic aquaculture (IMTA) farming technique was developed with the goal of resolving eutrophication by excess feed and feces as fish-farming by-products. A variety of seaweed species were tried to remove inorganic nutrients produced by fish farming. However, there have been few trials to use Sargassum fulvellum in an IMTA system, a species with a relatively wide distribution across regions with various habitat conditions, great nutrient removal efficiency and importance for human food source and industrial purposes. In this regard, our study tried to examine feasibility of using S. fulvellum in an IMTA system by analyzing growth characteristics of the species in an IMTA system comprising of rockfish (Sebastes shlegeli), sea cucumber (Stichopus japonocus) and the tried S. fulvellum (October 2011 - November 2012). We also monitored environment conditions around the system including current speed, water temperature and inorganic nutrient level as they may affect growth of S. fulvellum. S. fulvellum in the IMTA system, which were $15.72{\pm}5.67mm$ long at the start of the experiment in October 2011, grew to a maximum of $1093{\pm}271.13mm$ by May 2012. In September, seaweed growth was reduced to a minimum of $280{\pm}70.43mm$ in length. Then, S. fulvellum began to grow again reaching $325{\pm}196.19mm$ by November 2012. Wet weight of the seaweed was $4.01{\pm}1.89g$ at the start of the experiment and reached a maximum of $109.26{\pm}34.23g$ in May. The weight gradually declined to a low of $15.12{\pm}8.40g$ in September 2012. Weight began to increase once more, rising to $39.27{\pm}21.69g$ by November. During the experiment, the average velocity at the surface and the bottom was 6.5 cm/s and 3.4 cm/s, respectively. The water temperature ranged $5.0-23.5^{\circ}C$, which was considered suitable for growing S. fulvellum. Results of the study indicated no significant differences in inorganic nutrients between pre- and post-IMTA installation. It was thus concluded that S. fulvellum can be a suitable seaweed species to be used in an IMTA system.

• 한국수산과학회지
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• 제48권5호
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• pp.789-797
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• 2015

The concentrations of trace metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn) were determined in 49 surface sediment samples collected in Yeoja and Gangjin Bays on the south coast of Korea, which contain many shellfish farms, in order to assess the contamination level and to understand the spatial distribution of trace metals. The average metal concentrations in the surface sediments of both bays decreased in the order Fe > Mn > Zn > Cr > Pb > Cu > As > Cd > Hg. There were no differences in metal concentrations between shellfish farms and reference sites. The metal concentrations were significantly higher in Gangjin Bay than in Yeoja Bay. Notably, the Cu, Cd, and Hg concentrations were nearly twice as high in Gangjin Bay as in Yeoja Bay. A multivariate analysis showed a strong correlation among Fe, Mn, Zn, Pb, and Cr in the sediments of both bays, implying that the metal concentrations in the sediments in the study area were mainly dependent on natural processes, such as crustal components and diagenesis. Based on the geoaccumulation index and marine sediment quality guidelines (SQGs), the surface sediments in Yeoja and Gangjin Bays are not polluted by trace metals.

• Fisheries and Aquatic Sciences
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• 제22권12호
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• pp.30.1-30.11
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• 2019

Marine natural products isolated from the sponge Fascaplysinopsis cf reticulata, in French Polynesia, were investigated as an alternative to antibiotics to control pathogens in aquaculture. The overuse of antibiotics in aquaculture is largely considered to be an environmental pollution, because it supports the transfer of antibiotic resistance genes within the aquatic environment. One environmentally friendly alternative to antibiotics is the use of quorum sensing inhibitors (QSIs). Quorum sensing (QS) is a regulatory mechanism in bacteria which control virulence factors through the secretion of autoinducers (AIs), such as acyl-homoserine lactone (AHL) in gram-negative bacteria. Vibrio harveyi QS is controlled through three parallel pathways: HAI-1, AI-2, and CAI-1. Bioassay-guided purification of F. cf reticulata extract was conducted on two bacterial species, i.e., Tenacibaculum maritimum and V. harveyi for antibiotic and QS inhibition bioactivities. Toxicity bioassay of fractions was also evaluated on the freshwater fish Poecilia reticulata and the marine fish Acanthurus triostegus. Cyclohexanic and dichloromethane fractions of F. cf reticulata exhibited QS inhibition on V. harveyi and antibiotic bioactivities on V. harveyi and T. maritimum, respectively. Palauolide (1) and fascaplysin (2) were purified as major molecules from the cyclohexanic and dichloromethane fractions, respectively. Palauolide inhibited QS of V. harveyi through HAI-1 QS pathway at 50 ㎍ ml^-1 (26 μM), while fascaplysin affected the bacterial growth of V. harveyi (50 ㎍ ml^-1) and T. maritimum (0.25 ㎍). The toxicity of fascaplysin-enriched fraction (FEF) was evaluated and exhibited a toxic effect against fish at 50 ㎍ ml^-1. This study demonstrated for the first time the QSI potential of palauolide (1). Future research may assess the toxicity of both the cyclohexanic fraction of the sponge and palauolide (1) on fish, to confirm their potential as alternative to antibiotics in fish farming.