• Title/Summary/Keyword: Fishing net

Search Result 448, Processing Time 0.031 seconds

Assessment of domestic water supply potential of agricultural reservoirs in rural area considering economic index (경제성 지표를 활용한 농업용저수지의 생활용수 공급가능성 평가)

  • Yoon, Kwang-Sik;Choi, Soo-Myung;Chai, Jong-Hun;Yoo, Seung-Hwan;Choi, Dong-Ho;Yoon, Suk-Gun;Lee, Chang-Hee;Jung, Kyung-Hun;Shin, Gil-Chai
    • Journal of Korean Society of Rural Planning
    • /
    • v.23 no.1
    • /
    • pp.85-96
    • /
    • 2017
  • Existing agricultural reservoirs are considered as alternative source for the water welfare of rural area. In this study, domestic water supply potential of 476 reservoirs, which has storage capacity more than one million cubic meter, out of 3,377 agricultural reservoirs managed by Korean Rural Community Corporation (KRC) were investigated. Among them water quality of 136 reservoirs met the criteria of domestic water source which show less than COD 3 ppm. Available amount for domestic water of reservoirs, which meet the water quality, for ten year return period of drought was analyzed with reservoir water balance model. The results showed that 116 reservoirs has potential for supplementary domestic water supply while satisfying irrigation water supply. Finally, economic analysis using Net Present Value (NPV), Benefit-Cost (B/C) ratio, Internal Rate of Return (IRR), and Profitability Index (PI) methods was also conducted. The analysis showed that 19 reservoirs satisfied economic feasibility when water is provided from reservoir outlet but only 9 reservoirs meet the economic feasibility if water delivered from a reservoir to treatment plant by newly built conveyance canal. In order to supply the domestic water through the agricultural reservoirs managed by KRC, it is necessary to flexibly interpret and operate the 'Rearrangement of Agricultural and Fishing village Act'. Also, it is reasonable to participate in the water service business when there is a supply request from other Ministries. In addition, the KRC requires further effort to change the crop system for saving water and improve efficiency of irrigation systems.

Distribution And Abundance Of Copepods In The Gulf Of Alaska And The Bering Sea In Summer 1978 (하계(夏季) Alaska만(灣)과 Bering해(海)의 Copepods의 분포조성(分布組成))

  • Lee, Sam Seuk
    • 한국해양학회지
    • /
    • v.15 no.1
    • /
    • pp.17-33
    • /
    • 1980
  • The materials were obtained in the eastern Gulf of Alaska and the south- eastern Bering Sea during the cruise of the research vessel, Ohdae San, from July to October 1978. A total of 76 samples were taken by NORPAC net from a depth of 200 meters or less in coastal areas. 1. The surface water temperature in the coastal waters, varing from 9 to 10$^{\circ}C$, was lower than that in offshore waters which varied from 10 to 12.9$^{\circ}C$ in the eastern Gulf of Alaska. Thermocline was formed in the 30∼50 meter layer. Salinity of the coastal waters of Kenai Peninsula and Kodiak was 30 which was slightly lower than that of offshore. 2. The water temperature of the surface layer down to 30 meters varied from 7 to 10$^{\circ}C$ and from 1 to 9$^{\circ}C$ in the layer below 30 meters in the south-eastern Bering Sea. Meandering thermal front spread from the Alaska Peninsula to St. Matthew Island by way of St. Paul, and a thermocline was found at the 30∼50 meter layer Salinity ranged from 31.0 to 33.0 and that of northern and coastal waters was little lower than that of offshore. 3. Zooplankton biomass fluctuated from 0.1 to 23.6cc/10㎥ in the eastern Gulf of Alaska and 2.0 to 26.1cc/10㎥ in the south-eastern Bering Sea. Plankton was rich in the following areas, the inshore Kodiak waters, the northern Bering Sea, the Coastal waters and waters adjacent to Alutian islands however, poor in the central Bering Sea. In general, the south-eastern Bering Sea has a higher concentration of plankton volume than the eastern Gulf of Alaska. 4. Twenty three species representing 17 genera of copepods were identified from the samples. These were mostly composed of the cold water species, such as Pseudocalanus minutus, Acartia longiremis, Metridia lucens and Eucalanus bungii var. bungii. 5. The cold oceanic species were composed of Calanus cristatus, C.plumchrus, Metridia lucens, Eucalanus bungii var. bungii and Scolecithricella minor. The cold neritic species were Centropages abdominalis, Pseudocalanus minutus, Acartia longiremis, Eurytemora herdmanii, Pontella pulvinata, P. longipedata and Tortanus discaudatus. On the other hand, the warm oceanic species were Calanus tenuicornis and Oithona plumifera. The cosmopolitan species were Calanus finmarchicus and Oithona similis. 6. It was suggested that the cold oceanic species, Eucalanus bungii var. bungii and Metridia lucens in the south-eastern Bering Sea can be recommended as a valuable indicator species for finding the fishing grounds of demersal fish such as pollock and yellowfin sole in this area.

  • PDF

A Study on the Telemetry System for the Inhabitant Environment and Distribution of Fish-II -Current Direction, Velocity, Sea Ambient Noise and Distribution of Fishes- (어류의 서식환경과 분포생태의 원격계측에 관한 연구 - II -유향, 유속 및 환경소음과 어류의 분포생태-)

  • 신형일;안영화;신현옥
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.35 no.2
    • /
    • pp.129-135
    • /
    • 1999
  • The telemetry system for the current speed and direction, the underwater ambient noise and the distribution ecology of fishes was constructed by the author and his collaborator in order to product and manage effectively in shallow sea culture and setnets fisheries, and then the experiments for the telemetry system carried out at set net fishing ground located Nungpobay in Kojedo from October 1996 to June 1997. As this results, the techniques suggested in the telemetry system gave full display its function even though far away 1.5 km from transmitting part, but with the suggested telemetry system could not be ascertained relationship between physical environment and distribution ecology of fishes.

  • PDF

Resistance to Weathering with Materials for fisheries Facilities 1. Photodegradation Mechanisms of Netting Twines for Fisheries Facilities (수산시설용 재료의 내후성에 관한 연구 1.그물실의 자외선 열화기구)

  • 김태호
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.36 no.1
    • /
    • pp.45-53
    • /
    • 2000
  • To analyze the photodegradation mechanism of materials for fisheries facilities which stand for considerable time immediately under or even partly above the water surface, such as cage collar, cage net, stationary fishing gear, egc. after 900 hours exposure, weathering experiments on 3 kinds of netting twines like dyed polyethylene(PE) and nylon, and non-treated high strength PE(Hi-PE) were carried out by using xenon light source. The results obtained are as follows : It was observed by scanning electron micrograph(SEM) that a good protection by pigments was obtained in PE and nylon specimen, while crack was rapidly progressed at the surface of Hi-PE one owing to etching by UVR. There was a little increase in density resulting from reorientation of polymer chain, chain scission, etc. in Hi-PE specimen. A wide angle X-ray diffraction showed that 3 kinds of specimens had no fundamental changes in polymer crystalline structure considering each 2$\theta$ of diffraction peak. Remaining tenacity of netting twines was in order of PE, nylon, and Hi-PE after having been exposed to the effect of 900 hours. PE and nylon treated with stuffs were shown to be more resilient than non-treated Hi-PE as confirmed by SEM.

  • PDF

Hydroacoustic survey on distribution and density of fisheries resources in the Marado coastal area of Jeju, Korea (제주도 마라도 연안해역의 어업생물자원에 대한 분포밀도의 음향학적 조사)

  • SEO, Young-Il;OH, Taeg-Yun;CHA, Hyung-Kee;LEE, Kyounghoon;YOON, Eun-A;HWANG, Bo-Kyu;LEE, Yoo-Won;KIM, Byung-Yeob
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.52 no.3
    • /
    • pp.209-219
    • /
    • 2016
  • The survey was conducted to investigate biomass and distribution of fisheries resources using a quantitative echo sounder and a fixed gillnet around Marado coast of Jeju to obtain the scientific basic data for dispute resolution with a large purse seine fishery and coastal fishing and policy establishment of reasonable fisheries resources. Hydroacoustic surveys were conducted six times (November 28~29, 2015 (night), February 23~24, 2016 (night) and March 3~4, 2016 (night/day), March 30~31, 2016 (night/day)) using a quantitative echo sounder. The pelagic fish densities were relatively higher around Marado in November 2015, February 2016 and March 3~4, 2016. However, demersal fish densities were relatively higher in Jeju coastal waters on March 30~31, 2016. Catch data using fixed gill net were used to calculate biomass. Based on the hydroacoustic data, fish length-weight function and target strength information of dominant fish, the biomass of fishes were estimated as follow: 5.64 ton CV = 70.2% at night on November 28-29 2015, 7.14 ton CV = 35.8% of pelagic fish and 530.77 ton CV = 34.6% of demersal fishes at night on February 23-24 2016, 2.34 ton CV = 56.7% of pelagic fish and 571.93 ton CV = 40.3% of demersal fish at daytime, 1.39 ton CV = 48.4% of pelagic fish and 194.59 ton CV = 54.3% of demersal fish at night on March 3~4 2016, 0.37 ton CV = 72.9% of pelagic fish and 338.79 ton CV = 99.7% of demersal fish at daytime, 0.24 ton CV = 21.3% of pelagic fish and 68.61 ton CV = 53.8% of demersal fish at night on March 30~31 2016.

Annual changes of fisheries production in the shore of Jeonbuk Province, Korea (전북연안 어업자원생산량의 경년변화)

  • Park, Jong-soo
    • Journal of Fisheries and Marine Sciences Education
    • /
    • v.20 no.3
    • /
    • pp.400-409
    • /
    • 2008
  • The purpose of this study is to examine annual changes of coastal fisheries production in the shore of Jeonbuk Province in Korea. The catch data of an experimental vessel that used dredge nets were used to study fish species and catch per unit of fishing effort carried out from April 2002 to November 2004. The total number of fish species caught in 2002 was 23, and 15 in 2004. Total number of individuals were 6,008 and their total weight was 376.38 kg in 2002. In 2004, total number of fishes was 2,469, and their weight was 211.99 kg. The annual changes in fisheries production in the western coast of Korea were also analyzed from 1990 to 2007. The total near shore fisheries products in Korea has been relatively stable around 1,4000,000 metric tons to 1,8000,000 tons during this period. Similarly the Chungnam Province's annual fish catch had steadily risen from about 51,187 tons in 1990 to 85,637 tons in 2007. However, Jeonbuk Province's annual fish catch declined dramatically at around 133, 000 tons in 1990 to 45,000 tons in 2007. In summery, while the overall Korea's fisheries production has been stable over the past decade, that of Jeonbuk Province suffered drastic decline in the period. This decline was reflected in the decreased number of fish species, total individuals, and total catch in surverys performed with an experimental vessel.

Development and physical properties on the monofilament for gill nets and traps using biodegradable aliphatic polybutylene succinate resin (생분해성 지방족 폴리부틸렌 석시네이트 수지를 이용한 자망과 통발용 단일섬유의 방사기술 개발 및 물리적 특성)

  • Park, Seong-Wook;Bae, Jae-Hyun;Lim, Ji-Hyun;Cha, Bong-Jin;Park, Chang-Doo;Yang, Yong-Su;Ahn, Heui-Chun
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.43 no.4
    • /
    • pp.281-290
    • /
    • 2007
  • This study was aimed not only to develop the gill net and trap made of biodegradable monofilaments in order to prevent a ghost fishing and to protect marine ecosystem, but also to analyze their spinning process and physical properties. Results showed that the spinning speed of biodegradable polybutylene succinate(PBS) monofilament was estimated to be approximately 100m/min when spinning temperature and cooling water temperature were adjusted at $180^{\circ}C$ and $3^{\circ}C$, respectively. The breaking loads of PBS monofilaments were estimated to be $35.3kg/mm^2$ at ${\phi}0.2mm$, $46.5kg/mm^2$ at ${\phi}0.3mm$, and $49.7kg/mm^2$ at ${\phi}0.4mm$ in the dry condition, respectively. However, its breaking loads in the wet condition were reduced by 2.4-5.5%, compared to those in the dry condition. The knotted strength of PBS monofilament at ${\phi}0.2mm$ was estimated to be 98.6% of PE in the dry condition. The breaking load of PBS monofilament at ${\phi}0.3mm$ was evaluated to be 81.8% of PA, and its softness showed 3 times less than that of PA in the wet condition. The breaking load of PBS monofilament at ${\phi}0.4mm$ was 95.3% of PA, and its softness showed 1.6 times less than that of PA in the wet state. However, the load elastic elongations of two kinds of monofilaments were estimated to be 1% higher than that of PA.

Analysis of Economic Effects and Basic Theoretical Frameworks of ITQ Fishery Management - Focusing on the Red Crab Trap Fishery - (ITQ 어업관리의 기본이론과 경제적 효과분석 - 붉은대게어업을 중심으로 -)

  • Lee Sang-Go;Lee Yong-Soo
    • The Journal of Fisheries Business Administration
    • /
    • v.36 no.3 s.69
    • /
    • pp.119-139
    • /
    • 2005
  • The purpose of this paper is to provide information that will help both fishing industry and fisheries authority understand the principals of individual transferable quota(ITQ) fishery management. Theoretical frameworks and primary features of ITQ fishery managemenet are the assignment of exclusive property rights for harvest of common - property fisheries resources. An ITQ fishery management is fundamentally different from the conventional fishery management and it gives an individual fisherman the right to catch a specified quantity of fish, his quota. With ITQ, fisherman's quotas are transferable, in whole or in part. An ITQ is a property with certain rights of use, namely, the right to catch a given quantity and species of fish in a specific location during a specific period of time. The right is exclusive in the sense that no one else has the right to use the quota without the owner's permission. The property may be assigned, traded, and exchanged; i.e., the owner has the right to transfer an ownership to others. An ITQ fishery management leads to both economic efficiency and resource conservation. Motivations to overexploit stocks and to overcapitalize should be lessened because fishermen no longer have to compete for limited resources. There are significant positive net benefits and advantages with ITQ fishery management than without. The potential benefits and advantages of ITQ fishery management include increased profits, economic stability, improved product quality, safer working conditions, less gear conflict, elimination of the race - to - fish phenomenon, less by - catch, less gear loss, improved investment climate, mitigation of market gluts, waste reduction, addition to fisherman's wealth, and compensation for fisherman exiting the fishery. As an independent observe to Red Crab Trap Fishery some of the benefits, problems, and effects, an ITQ fishery management in Red Crab Trap Fishery is still far from to be implemented. Many different and difficult aspects (biological, socioeconomics, administrative) are involved considering the implementation of ITQ fishery management in Red Crab Trap Fishery. Among other fishery management tools, the implementation of ITQ fishery management in Red Crab Trap Fishery is considered to be the best in achieving the better conservation of fisheries resources and their more economic and rational exploitation. Korean fisheries authority should pay great attention to the experience of the economic effects of the ITQ fishery management in Red Crab Trap Fishery in the hope of being able to implement at least some of those experiences into the Korean fishery management.

  • PDF

Studies on the improvement of the productivity of purse seine fishery-III - The characteristics on the motion with the flow velocity of model purse seine of the subjective power block and triplex during pursing - (선망어업의 생산성 향상에 관한 연구-III - 죔줄 체결시 파워불록과 트리플랙스용 선망 모형의 유속에 따른 운동특성 -)

  • Kim, Suk-Jong
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.43 no.1
    • /
    • pp.12-27
    • /
    • 2007
  • This fundamental studies on for the productivity improvement and laborsaving of purse seine fishery. Given the difficulty posed from the distortion of net shape caused by the external forces, such as tide, at the time of shooting and pursing, we set the 4 steps of 0, 2, 4 and 6cm/sec in flow velocity in the flume tank for the experiment in order to examine those characteristics. We used two model seines designed on the scale of 1 to 180 based on the power block seine, which is the mackerel purse seine generally used in the near sea of Jeju Island and triplex seine, which is the mackerel purse seine of one boat system fishing expected in the future, for the experiment, and interpreted the characteristics of several motion in water, such as the shape of seine, the change in tension and area during pursing and its the analysis results are as follows. Though the experiment could be conducted up to 6cm/sec of flow velocity that was defined, the experiment could not go on because of the severe distortion in the seine at the flow velocity in excess of 6cm/sec. As for the depth of leadline and reduction rate of side area of seine when the pursing is connected, P seine turned out to be slightly higher than T seine, and the hauling speed and reduction rate of upper area of seine were found similar to each other. The correlation between the hauling time (Ht) and depth of lead line (Dhp, Dht) of P seine and T seine can be expressed by the equation, that is, Dhp=(0.99Pt-7.63)Pt+69.01, Dht=(1.03Pt-7.73)Pt+66.74. The correlation between the hauling time and hauling velocity (Hpp, Hpt) can be expressed by the equation, that is, $Hpp=-0.06Ht^2+0.88Ht+0.78,\;Hpt=-0.05Ht^2+0.81Ht+0.98$ here, Pt is pursing time. And the correlation between the pursing time and the reduction rate of side area (sArp, sArt) can be expressed by the equation, that is, $sArp=-0.48Pt^2+14.79Pt-16.74,\;sArt=-0.45Pt^2+14.56Pt-16.48$. The reduction rate of upper area of seine (tArp, tArt) can be expressed by the equation, that is, $tArp=0.34Pt^2-0.66Pt-0.74,\;tArt=0.34Pt^2-0.27Pt-1.80$. In addition, the correlation between the pursing time and tension of purse line (Tep, Tet) can be expressed by the equation, that is, $Tep=2.79Pt^2+2.26Pt-0.60,\;Tet=2.14Pt^2+8.08Pt-27.50$.

Factors affecting the Occurrence of Rural Vacant Houses (농촌 지역 빈집 발생의 영향 요인)

  • Kim, Sung-Rok;Kim, Doo-Soon
    • Journal of Cadastre & Land InformatiX
    • /
    • v.48 no.2
    • /
    • pp.65-77
    • /
    • 2018
  • It is very important to understand the factors affecting the occurrence of vacant houses in research on them. The purpose of this study is to analyze the factors affecting the rural vacancy occurrence. This study set 121 research areas and selected eight independent variables (Aged house rate, housing transaction rate, house diffusion ratio, local extinction index, net migration rate, regional aging index, the ratio of the number of employees to population and financial independence rate) and one dependent variable (vacant house rate). As a result of the study, first, both Model 1 for the entire general agricultural fishing village area and Model 2 for the county (gun) area were statistically significant, there was no problem with the independence of residual. Second, local extinction index and aged house rate had a statistically significant positive (+) relationship in both Model 1 and Model 2. Third, diffusion ratio of house had a statistically significant positive (+) relationship only in Model 1, and housing transactions rate had a statistically significant negative (-) relationship in Model 2. The implications of the study were drawn as follows: First, the increase in the house diffusion ratio without growth in households and population suggests the increase of the probability of the vacancy occurrence in the area, and the higher the aged house rate, the higher the probability of the vacancy occurrence. Second, for the revitalization of housing transactions, it is necessary to have an investment inflow in the area for mid- to long-term development. Third, local extinction index has a significant relationship with vacant house rate, it is necessary to introduce a local revitalization policy from a long-term perspective for the permanence of the area.