• Title/Summary/Keyword: Fish monitoring

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Evaluation technique for efficiency of fishway based on hydraulic analysis (수리해석을 기반으로 어도 효율을 평가하는 기법)

  • Baek, Kyong Oh
    • Journal of Korea Water Resources Association
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    • v.52 no.spc2
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    • pp.855-863
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    • 2019
  • The efficiency of fishway installed in rivers can be directly evaluated by means of fish monitoring. On the other hand, when it is difficult to monitor the fish in certain conditions, or when planning a fishway, the efficiency can be evaluated indirectly through the hydraulic analysis. In this study, the hydraulic analysis technique for evaluating the efficiency of a fishway was presented. The River-2D model with the fish physical habitat module was used for the analysis of the attraction efficiency, and the weighted usable area was proposed as an index of the efficiency. In the analysis of passage efficiency, the three-dimensional model, Flow-3D, was used as an evaluation tool to describe the fluid behavior on a hydraulic structure with free surface. The ice-harbor type fishway at Baekgok weir in the Deokcheon River was selected as a test-site, and the efficiency was estimated using the hydraulic analysis. And then it was compared with fish monitoring data acquired from the river. As a result, it is difficult to replace the hydraulic analysis results with the efficiency quantitatively, but it can help to grasp the general tendency.

Monitoring of the mortalities in oliver flounder (Paralichthys olivaceus) farms of Korea (한국 양식 넙치 폐사피해 모니터링)

  • Shim, Jae-Dong;Hwang, Seong-Don;Jang, Soo-Young;Kim, Tae-Wan;Jeong, Ji-Min
    • Journal of fish pathology
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    • v.32 no.1
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    • pp.29-35
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    • 2019
  • A monitoring was performed to survey the mortalities that had occurred in the aquaculture farms of olive flounder (Paralichthys olivaceus) in South Korea from 2015 to 2017. The indirect inquiry for entire farms and the sample survey for selected farms were carried out. The aquatic organism disease inspectors, who have a national license for the diagnosis and prevention of aquatic organism diseases and a have close relationship with the farms, investigated the rates and causes of mortalities according to the standard manual. The mortality rate by sample survey of farms in 2015, 2016, and 2017 were 24.78% (Chunnam: 17.86%, Jeju: 28.69), 30.19% (Chunnam: 24.45%, Jeju: 32.65), and 21.59% (Chunnam: 10.57%, Jeju: 26.00%), respectively. The major cause of mortality was scuticociliatosis, and the mortality caused by viral hemorrhagic septicemia and emaciation disease (Jeju) were also high. Our results can contribute to effective establishment prevention of epidemics system and acquired status as a disease-cleansing country.

Study of Fish Monitoring for of Exotic Fishes Management of Ecological Park at Nakdong River 2 (Daejeo Ecological Park) (낙동강 생태공원 지역 외래어종 관리를 위한 어종 모니터링 연구 2 (대저생태공원))

  • Joon Gu Kang;Sung Jung Kim;Hong Koo Yeo
    • Ecology and Resilient Infrastructure
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    • v.10 no.4
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    • pp.193-200
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    • 2023
  • Influx of exotic fishes is the problem of fish management. The reason why interest on river environment was increased. Recently, River project was conducted to consider environmental function on the ecosystem and Eco-Diversity. Therefore, farmlands structure along the river was removed such as vinyl greenhouse. Daejeo ecological park was built in 4 River project. Daejeo ecological park have significance habitat for migratory birds and eco-diversity. In spite of nature river improvement, ecological system in river will be break down by exotic fishes. This study was conducted to investigate analyze the fish faun and prevailing species occupancy in Daejeo ecological park. This data will be used to make the management plan of exotic fishes in ecological park around Daejeo ecological park.

Chemical Analysis of Transplanted Aquatic Mosses and Aquatic Environment during a Fish Kill on the Chungnang River, Seoul, Korea

  • Lee, Joohyoung;Green, Perry-Johnson;Lee, Eun-Ju
    • Animal cells and systems
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    • v.6 no.3
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    • pp.215-219
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    • 2002
  • In mid-April, 2000, hundreds of thousands of fish floated dead on the Chungnang River, one of the small branches of the Han River in Seoul. We examined the causes of the accident in detail, through analysis of monitorinq data from the Han River Monitoring Project, which employed the transplanted aquatic moss, Fontinalis antipyretica. This allowed investigation of another possible cause of the fish kill: release of trace metals into the river from industrial sources during the rainfall event. In addition, we aimed to verify the usefulness of aquatic mosses as bioindicators of the event. Water samples collected 48 h after the fish kill exhibited low pH and high Total-N and Total-p, indicating that acidic compounds rich in nitrogen and phosphorus might be a major contaminant. BOD and COD were also very high. On the whole, the conditions of the river water were degraded at that time. Distinct trends were not observed in the chlorophyll phaeophy-tinization quotient and photosynthesis rate of transplanted mosses. How-ever mosses sampled soon after the accident exhibited the lowest values for those variables (P < 0.01), suggesting that stress factors in the river were diluted out over time. Heavy metals with characteristics of industrial effluents (Cr, Pb, Zn, Fe, Cu, and Cd) increased (p < 0.01), indicating that they were unlikely to be major causes of the accident.

Monitoring of scuticociliatosis of olive Flounder (Paralichthys olivaceus) farm in Jeju, Korea from 2007 to 2014 (2007~2014년 제주지역 넙치(Paralichthys olivaceus) 양식장의 스쿠티카증 발생 동향 조사)

  • Kang, Bong Jo;Jang, Yeoung Hwan;Jhon, Bong Kun;Park, Byum Hee;Jin, Chang Nam
    • Journal of fish pathology
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    • v.28 no.3
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    • pp.165-169
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    • 2015
  • Occurrence of Scuticociliatosis in olive flounder farm of Jeju was monitored from 2007 to 2014. As a result, 23.8~36.4% of referred samples were diagnosed as Scuticociliatosis. Based on fish size, the highest incidence (50.5%) was found in fish with size of 10~20 cm.

Investigation of Reportable Communicable Diseases and Parasites in Aquatic Organisms Living in the Estuary of the Han River (한강 하구에 서식하는 수산생물의 법정전염병 및 기생충 감염 조사)

  • Kim, Jin Hui;Song, Jun Young;Lee, Jung-Ho;Hur, Jun Wook;Kwon, Se Ryun;Kwon, Joon Yeong
    • Korean Journal of Ecology and Environment
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    • v.52 no.4
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    • pp.306-315
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    • 2019
  • The estuary of the Han River constantly suffers from pollutants and pathogenic microorganisms which could cause serious damage to aquatic organisms living there. Despite of this potential risk, it is hard to find any reliable scientific reports on the status of reportable disease infection to the organisms living in this area. In this study, cyprinid fish and crustaceans in Jeonryu-ri, a region of the Han River estuary, were investigated for the infection by representative reportable communicable diseases(SVC, spring viraemia of carp; KHVD, koi herpesvirus disease; EUS, epizootic ulcerative syndrome; WSD, white spot disease) and parasites. Peripheral fish and primary freshwater fish were observed in Jeonryu-ri with cyprinid caught most frequently. Crustaceans were mostly marine species. No positive bands to any of the reportable diseases were produced in any of the fish and crustacean examined in this study by PCR. No trace of Clonorchis sinensis, a liver fluke potential threat to human health, was detected in any of fish samples. However, many fish were infected by metacecaria of other flukes, and other various parasites such as nematode, cestode, copepod, monosite and acanthocephalan. These results suggest that important aquatic organisms in the Han River estuary is not seriously polluted yet. However, it is important to keep monitoring the diseases since the water quality in this region is constantly changing, and devastating influence of infectious diseases is unpredictable. Further, it is required to expand monitoring area toward upstream and increase the number of fish for examination.

Behavioral analysis of rock bream Oplegnathus fasciatus reveals a strong attraction potential for sea urchin extracts

  • Duminda, S.K. Tilan Chamara;Kim, Yeo-Reum;Kim, Jong-Myoung
    • Fisheries and Aquatic Sciences
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    • v.24 no.1
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    • pp.32-40
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    • 2021
  • Monitoring fish movement is important to understand how physiology adapts to environmental change. To explore the applicability of a video tracking system for determining if chemical cues attract or repel aquatic animals, the movement patterns of rock bream, Oplegnathus fasciatus, were analyzed upon exposure to various materials, including extracts of sea urchin, rock worm, bait worm, krill, barley kernel, and commercial fish feed. Pellets were prepared by mixing freeze-dried tissues with a cellulose and corn flour mixture. Behavioral analysis was carried out with five fish that had been acclimated in the adaptation zone of a Y-shaped tank. Preference toward chemical cues was quantified by assessing the frequency rock bream were observed in a discrete zone around the test material located at the end of each arm and the duration each fish stayed in each zone. The analysis of fish movement upon exposure to commercial feed and barley kernel at each end, respectively, indicated a clear preference toward the feed relative to the barley kernel. Movement responses were further tested with pellets containing extracts of sea urchin, one of the species collected on a large scale, and other materials including krill and worms. A stronger preference toward sea urchin (100%) was observed based on the duration of stay in the test zone, compared to krill (90.1 ± 44.2%), bait worm (81.1 ± 39.1%), rock worm (73.7 ± 28.9%), and barley (63.9 ± 25.9%), under the conditions tested. A detailed comparison of rock bream movements toward each material revealed significant differences in frequency and duration, respectively, between pairs of test materials including krill (74 ± 29.8 and 375.6 ± 118.9) vs. rock worm (41.5 ± 18.7 and 160.2 ± 42.6), krill (86.3 ± 22.9 and 477.1 ± 84) vs. bait worm (36.2 ± 5.5 and 166.1 ± 50.7), and rock worm (45.9 ± 26.2 and 213.7 ± 100.1) vs. bait worm (34.6 ± 21.7 and 159.5 ± 98.5). Rock bream exhibited preference for the test materials in the following order: commercial fish feed > sea urchin > krill > rock worm > bait worm > barley. The results suggest a higher potency of sea urchin extract as a rock bream fishing bait compared to the other materials that are used as commercial bait.

Changes in hematoserological profiles and leukocyte redistribution in rainbow trout (Oncorhynchus mykiss) under progressive hypoxia

  • Roh, HyeongJin;Kim, Bo Seong;Kim, Ahran;Kim, Nameun;Lee, Mu Kun;Park, Chan-Il;Kim, Do-Hyung
    • Journal of fish pathology
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    • v.33 no.1
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    • pp.23-34
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    • 2020
  • In recent years, global warming is causing dramatic environmental changes and deterioration, such as hypoxia, leading to reduced survival rate and growth performance of farmed aquatic animals. Hence, understanding systemic immuno-physiological changes in fish under environmental stress might be important to maximize aquaculture production. In this study, we investigated physiological changes in rainbow trout exposed to hypoxic stress by monitoring changes in blood chemistry, leukocyte population, and expression levels of related cytokine genes. Hematological and serological factors were evaluated in blood obtained from rainbow trout sampled at a dissolved level of 4.6 mg O2 L-1 and 2.1 mg O2 L-1. Blood and head kidney tissue obtained at each sampling time point were used to determine erythrocyte size, leukocyte population, and cytokine gene expression. The level of LDH and GPT in fish under progressive hypoxia were significantly increased in plasma. Likewise, the (Granulocyte + Macrophage)/lymphocyte ratio (%) of fish exposed to hypoxia was significantly lower than that in fish in the control group. Such changes might be due to the rapid movement of lymphocytes in fish exposed to acute hypoxia. In this study, significant up-regulation in expression levels of IL-1β and IL-6 gene appeared to be involved in the redistribution of leukocytes in rainbow trout. This is the first study to demonstrate the involvement of cytokines in leukocyte trafficking in fish exposed to hypoxia. It will help us understand systemic physiological changes and mechanisms involved in teleost under hypoxic stress.

Use of the cast net for monitoring fish status in reservoirs distributed in the Korean peninsula

  • Yoon, Ju-Duk;Kim, Jeong-Hui;Lee, Hae-Jin;Jang, Min-Ho
    • Journal of Ecology and Environment
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    • v.38 no.3
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    • pp.383-388
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    • 2015
  • Reservoirs consist of two different environments, the littoral and the pelagic zone, and different fishing gear is commonly used in each zone-gill nets in the pelagic zone and electrofishing in the littoral zone. However, an active fishing gear, the cast net, is normally used instead of electrofishing for scientific studies in South Korea. In order to estimate cast net effectiveness for determining fish status in reservoirs, the study was conducted at 15 reservoirs with two different fishing gears: a cast net in the littoral zone and gill nets in the pelagic zone. When combining catches of both gears, species richness increased substantially compared to using one gear only. There was a size difference in fish caught by each net, and small fish were predominantly caught with the cast net due to its small mesh size (7 mm). The combined length of six species, used for length-weight relationship analysis, collected with the cast net was smaller than that collected with gill nets (independent t-test, P < 0.05). In this study, cast net sampling provided sufficient data for the littoral zone, but not enough to identify the overall fish assemblage in studied reservoirs. Utilization of only one gear can therefore lead to substantial underestimation of fish status, and a combination of both gears is recommended for determining more reliable estimates of fish status in reservoirs.

Estimation of Fish School Abundance by Using an Echo Sounder in an Artificial Reef Area (어군탐지기를 이용한 인공어초 주변의 어군량 추정)

  • HWANG Doo Jin;PARK Ju Sam;LEE Yoo Won
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.37 no.3
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    • pp.249-254
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    • 2004
  • The hydro-acoustic method is widely used for estimating biomass and distribution of fisheries resources along the coast and in the ocean. High costs and time are necessary to construct systems for this method and to initially educate specialists. It has been used in fisheries of advanced nations like Japan and Norway, because it is more efficient than other methods. In order to research the behavior of fish around an artificial reef using an echo sounder, volume backscattering strength (SV) and fish per cubic meter (FPCM) of darkbanded rockfish around the model artificial reef in a water tank were measured. Moreover, behavior of fish was observed in an adjacent artificial reef, which was constructed at Tongyeong marine ranching area. Following that, an acoustics survey was conducted at Mirukdo around the Tongyeong marine ranching area, in order to understand the spatial distribution and strength of fisheries resources. Very high patches of fish were found in a wide area around the artificial reef. It is thought that an approaching fish school around the artificial reef can be measured accurately by using an echo sounder of high resolution. Moreover, use of other monitoring methods like of diving or ROV simultaneous with an echo sounder is required in order to grasp the species and ecology of fish inhabiting the area around the artificial reef.