• 한국수산과학회지
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• 제13권1호
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• pp.33-44
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• 1980

부착 생물에 관한 연구는 선박, 해수 이용시설, 수산 양식업 둥의 방제대책과 관련하여 부착 생물의 종류, 부착 량, 성장도 및 계절적 변화 둥의 연구가 중요한 문제하고 생각한다. 특히 양식시설이 밀집한 진해만 해역의 굴 양식 시설에 부착하는 대부분의 생물들이 Ascidicea, Crustacea, Cirripedia, Bivalvia, Bryozoa, Polychaeta, marine algae 등이며, 이들 가운데 피해가 심한 다모환충류에 관하여 분류학적인 연구를 시도하였던 바 수하연의 양식 굴 사이에서 많은 양의 갯지렁이류를 얻었기에 보고 한다. 수하연에 서식하는 갯지렁이류는 제2부착성(Kazihara, 1964)의 갯지렁이류로서 왕관 모양의 큰 아가미 혹은 몸앞 부분에 실모양의 감각 촉수를 가지고 굴에 피해를 입히는 짧은수술갯지렁이 Loimia medusa, 미끈꽃갯지렁이 Myxicola infundibulum와 제1부착성으로서 굴 패각, 양식 시설 등에 석회질의 집을 형성시켜 피해를 입히는 우산관덮개꽃갯지렁이 Hydroides ezoensis, 둥근구멍환덮개꽃갯지렁이 Dexiospira alveolatus 등의 7과 12속 13종을 보고한다. 이 가운데 새날개갯지렁이 Chaetopterus variopedatus와 둥근구멍관덮개꽃갯지렁이 Dexiospira alveolatus는 한국 미기록종이다.

• 한국수산과학회지
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• 제54권4호
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• pp.418-425
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• 2021

The effects of an aquaponic system based on biofloc technology (BFT-AP) were analyzed for eel Anguilla japonica as aquaculture species and caipira Lactuca sativa as the cultivated crops. The rate of weight gain rate by the eels was 178% (BFT-AP 200 head) > 136% (BFT-AP 100 head) > 100% (BFT). The eel body weight in the BFT-AP (200 head) significantly increased when compared to the BFT only eel group (P<0.05). The weight of the upper layer of caipira was 91±8.5 g (200 head) > 90±8.9 g (100 head) > 48±8.3 g (Hydroponic crop, HP). The crop growth in all BFT-AP groups was higher than the control, the hydroponic group. The total ammonia nitrogen (TAN) and NO₂^--N concentrations decreased in the BFT-AP group when compared to the BFT group. It was possible to remove nitric acid from the aquaponics system and reuse it as eel rearing water. Although some nutrient concentrations were low in BFT when compared to HP, the nutrient concentration was sufficient for plant growth. The results show that BFT has the potentially to provide a sustainable aquaponic system.

• 한국수산과학회지
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• 제54권5호
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• pp.660-667
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• 2021

In recent years, myxosporean infection from the cultured olive flounders Paralichthys olivaceus, have been frequently observed in Jeju island, South Korea. This study aimed to compare histopathological and molecular-biological methods of examining myxosporean infection from these flounders. Samples were obtained from affected individuals exhibiting emaciation or abdominal distention and a polymerase chain reaction (PCR) indicative of Parvicapsular anisocaudata, Enteromyxum leei and Kudoa septempunctata were initiated. Histopathological examination were conducted with H&E stained tissue sections, and then in-situ hybridization (ISH) reaction were processed with selected sections using P. anisocaudata, E. leei, K. septempunctata and Scuticociliate probes. Renal and intestinal tissue degeneration were common symptoms associated with all samples. Sever glomerular and renal tubular degeneration were evident, as were intestinal epithelial desquamation and spore formation in the epithelial cells. The results of conventional PCR analysis and ISH reactions revealed differences, and we suspect that various microparasites may have been associated with the symptoms manifested.

• 한국수산과학회지
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• 제55권5호
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• pp.541-548
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• 2022

Biofloc technology (BFT) systems provides an additional protein source for fish by converting waste in microbial flocs. Therefore, we aimed to determine the difference in the protein levels of the diet of Far Eastern catfish Silurus asotus reared in BFT and FW systems. We applied a two-way (six protein levels × two aquaculture systems) ANOVA design. We formulated six experimental diets to contain different protein levels (CPs)- 20%, 25%, 30%, 35%, 40% and 45%-referred to as the CP20, CP25, CP30, CP35, CP40 and CP45 diets, respectively. We randomly distributed 900 fish into 36 (18 each for BFT and FW), 300 L tanks (25 fish/tank) with three replications of each diet for 4 weeks. The weight gain (WG) and specific growth rate (SGR) considerably improved as the dietary protein level increased in the formulated diets. The BFT fish showed higher growth performance with any experimental diet than the FW fish. The growth performance of the fish fed the BFT-CP35 diet was higher than that of the fish fed the FW-CP45 diet. In conclusion, the cultivation of Far Eastern catfish (S. asotus) in BFTs can be carried out under reduced dietary protein levels.

• 한국양식
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• 제15권2호
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• pp.22-29
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• 2003

• 한국수산과학회지
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• 제56권1호
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• pp.99-108
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• 2023

In this study, changes in biofloc-related and pathogenic bacteria in both low and high concentration biofloc breeding water planted with the halophyte (Triglochin maritimum were investigated). In the low-concentration biofloc breeding water, the ratio of bacteria related to the nitrogen cycle was initially 59.57% and, it decreased to 26.57% at the end of the experiment while other bacteria (excluding nitrogen-cycling bacteria and vibrios) increased from 38.75% to 73.43%. However, the planted experimental group maintained a relatively high ratio of nitrogen cycling bacteria at 58%. In the high-concentration experimental group, bacteria related to the initial nitrogen cycle, non-pathogenic vibrios, and pathogenic vibrios were 11.60, 36.28, and 20.14%, respectively. Finally, nitrogen-cycling bacteria were 36.47% in the control group and 37.55% in the planted group. The total number of vibrios decreased by 46.54% in the planted group and 48.01% in the control group, indicating a significant decrease in both experimental groups. However, the residual rate of pathogenic vibrios was 4.48% in the control group and 0.54% in the planted group. Overall, the planted group showed decreasing harmful bacteria and increasing useful bacteria.

• 한국수산과학회지
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• 제56권4호
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• pp.401-410
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• 2023

This study examined the characteristics of eel Anguilla japonica sperm using the CASA (computer-assisted sperm analysis) system and attempted to provide the composition for artificial seminal plasma by regulating of inorganic elements. Sperm samples were first divided into four groups based on motility and progressive motility: (A) 0-10%, (B) 10-40%, (C) 40-70%, and (D) 70-100%. For observing sperm velocity variations, VCL, which is curve motion velocity, showed the highest values in all groups. The directional factor, beat cross frequency, was lower in higher activity groups, showing an opposite correlation with sperm activity. The head sizes of spermatozoa in higher activity groups were significantly larger than those in lower activity groups. The Na⁺ and K⁺ ions were important in the inorganic composition of seminal plasma in this species. Furthermore, regulating the composition in artificial seminal plasma improved the formula compared to the existing element, exhibiting 120 mM Na and 30 mM K when the sperm was conserved for a long time and 120 mM NA and 40 mM K when the sperm was conserved for a short time.

• 한국수산과학회지
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• 제56권6호
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• pp.930-935
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• 2023

This study aimed to analyze the structure of the value chain of the olive flounder aquaculture industry to increase the value of this industry. Based on the value chain theory, olive flounder aquaculture industry activities were classified as primary and support activities. The primary activities included seed production, fish production, producer distribution, consumer distribution, and consumption. The support activities were production infrastructure, organization and specialization, R&D, and government policy. A survey was conducted on the costs of seed and fish production in the primary activities to investigate the business structure, and the distribution structure was analyzed to examine distribution costs and margins. In the support activities, the recent trends in R&D and government policy were mainly examined, based on which, a measure to reduce costs and maximize profits was suggested. It is necessary to reduce costs across the production processes by improving seed quality and reducing labor, feed, and management costs, which are strongly associated with support activities. Therefore, lowering costs will be possible in the olive flounder aquaculture industry when R&D outcomes, such as species development, feed quality improvement, and aquaculture system development, are stably diffused and applied in tandem with government policy regarding the industry.

• 한국수산과학회지
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• 제55권5호
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• pp.612-624
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• 2022

A novel Gram-positive, motile, non-spore forming aerobic marine bacterium, designated 107-1^T was isolated from tidal mud collected in Gyehwa-do, South Korea. Cells of strain 107-1^T were short rod or coccoid, oxidase negative, catalase positive and grew at 10-40℃ (with optimum growth at 25-30℃). It utilized menaquinones MK-7 and 8 as its respiratory quinones and its major fatty acids were anteiso-C_15:0 (37.9%), iso-C_16:0 (14.9%), and iso-C_14:0 (10.8%). Phylogenetic analysis based on 16S rRNA gene sequences revealed a distinct clade containing strain 107-1^T and close species Planococcus ruber CW1^T(98.52% sequence similarity), P. faecalis KCTC 33580^T(97.67%), P. kocurii ATCC 43650T(97.48%), P. donghaensis DSM 22276T(97.47%), and P. halocryophilus DSM 24743T(97.37%). Strain 107-1^T contains one circular chromosome (3,513,248bp in length) with G+C content of 44.6 mol%. Estimated ranges for genome to genome distance, average nucleotide identity, and average amino acid identity comparing strain 107-1^T with close taxa were 20.3-34.8%, 77.9-86.9%, and 73.6-92.8%, respectively. Based on polyphasic analysis, strain 107-1^T represents a novel species belonging to the genus Planococcus.

• 한국해양생명과학회지
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• 제1권1호
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• pp.50-55
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• 2016

본 연구결과 glucose, NH3, AST, ALT는 4℃일 때 가장 높게 나타났으며, glucose와 AST는 4℃일 때 다른 염분구보다 26 psu에서 유의하게 높았다. 참전복에는 총 18가지 FAA가 존재하였으며, taurine, arginine, glutamic acid, alanine, glycine, lysine이 전체의 90% 가량을 차지하는 우점 FAA로 나타났다. Taurine은 30 psu 이상에서는 수온 간 유의한 차이가 없었으나, 26 psu에서는 6, 8℃일 때 유의하게 증가하였다. Glycine은 수온이 낮아질수록 유의하게 감소하여 6℃일 때 가장 높게 나타났다. 따라서 참전복은 30~34 psu, 8~10℃에서의 조건으로 수송 시 스트레스를 최소화할 수 있을 것으로 여겨진다.