This paper describes the development of moving watched chamber. For the most part, the watched chamber have been located in the inner-bay. But, there are many problems of sea-water pollution. Therefore, the watched chamber must be relocated to undeveloped coastal area. The watched chamber which is located in the bay has a bit of damage by bad weather. But, the moving watched chamber would be exposed to bad water. It is desirable to improve the system of chamber. If we make a good design of the moving watched chamber with studying of waves and hydrodynamics, it would be possible to culture fish at the coastal sea area. When a fixed system is changed into a movable one, we can obtain the following advantages: 1. The possibility of diminishing the sea water pollution, easying the overcrowded state in a inner-bay farm, and relieved of limitation caused by bad conditions such as waves, red tides and terrains. 2. It would be easy not only to move the watched chamber system in accordance with weather conditions or occurrence of red tides, but also to select good sites for watched chamber fishes. 3. Transportation and good supervision with the automated design system can results with the effectiveness which increases the amount of aquatic products.
군산대학교 실습선 해림 3호의 조종성능을 파악하기 n이하여 GPS 보다 그 측립정도가 더 높은 DGPS를 이용하여 종회권 측정을 행하고, 이를 재래식 측정방법인 부표방입반법과 비교 검토하였으며, 그 결과를 요약하면 다음과 같다. 1. DGPS에 의한 선회권측정의 정도를 파악하기 위하여 육상에서 50m의 선회시험을 행한 결과 측위오차는 1.5m 이내 였다. 2. DGPS에 의한 선회권측정은 속력별, 타각별, 좌우선회별로 각각 그 특성이 잘 나타낼 수 있도록 정확하게 측정 할 수 있었다. 3. 부표방위반법에 의한 선회권측정은 타각을 크게 하여 그 선회권이 작을 때는 DGPS의 것과 같이 비교적 정확하게 측정할 수 있으나, 타각을 작게하여 선회권이 클 때는 방위오차가 크기 때문에 정확하게 측정할 수 없었다. 4. DGPS에 의한 해림 3호의 선회경(DT)은 타각 35。~5。일 때, 미속에서는 선박의 수선간장 (Lpp)상의 2.6~15.0배, 반속에서는 2.8~16.6배, 전속에서는 3.1~17.4배로 나타났었고, 부표방위반법에 의한 선회경은 각각 2.4~9.5배, 2.6~9.6배, 3.2~12.2배로 나타났었다
모형 그물에 대한 어군행동의 수치모델링에 관한 연구의 일환으로서 어군행동의 모델링을 위하여 어군행동을 나타내는 운동방정식을 구성하는 각종 힘들의 parameter를 추정하기 위한 기초자료를 제공하고자, 모형 그물을 설치하지 않은 상태에서의 유속 변화에 따른 무지개송어의 유영행동을 화성처리하여 각 개체 위치좌표로부터 계산된 유영속도, 유영깊이, 수조의 변과 개체 사이의 거리, 개체상호간의 최근접거리, 어구의 3차원적 구조 등의 유역특성을 조사 분석한 결과는 다음과 같다. 유영궤적으로부터 무지개송어의 유영행동을 살펴보면, 정수상태에서는 수종 중앙부에서 유영하는 빈도가 높았으며, 수조 벽면으로부터 상당히 떨어져서 유회운동을 하는 것으로 나타났다. 정수상태에서의 평균 유영속도는 21.6~23.6cm/sec(2.5~2.9BL cm/sec)로서 개체수가 많을수록 체장당 유영속도가 빠른 것으로 나타났으며, 유속의 변화에 따른 어군의 평균유영속도는 유속이 증가할수록 유영속도도 증가하여 유속이 25cm/sec인 경우에는 유영속도가 30.6 cm/secd(3.8BLcm/sec)에 달하였다. 어군의 평균 유영깊이는 17~38cm로서 주로 중층의 깊이에서 유영하였으며, 유속이 빨라질수록 유영 깊이가 깊어지고 유영 깊이의 변화가 적어졌다. 수조의 벽과 개체 사이의 평균 거리는 17.6~21.4cm였으며, 유속이 빨라질수록 수조의 벽과 개체사이의 거리가 다소 멀어지는 경향을 나타내었다. 개체상호간의 최근거리는 개체수가 많을수록 가까워지며, 유속의 변화에 따른 개체상호간의 최근접거리 평균치는 3.0~5.9cm(0.4~0.7BL cm)로 나타났다. 어군의 3차원적 구조는 군을 형성하는 개체수가 증가함에 따라 군의 형상이 길이, 폭 및 깊이의 모든 방향으로 넓어지며, 유속이 빨라질수록 길이방향과 폭 방향의 크기가 깊이 방향에 비해 상대적으로 커져 각 방향의 평균 상태비는 2.8 : 2.7 : 1이었다
원격어군탐지기를 시험제작하여 정치망의 원통, 비탈그물 및 헛통에 원격어군탐지기와 기록식어군탐지기를 각각 설치하고, 1994년 10월 26~27일에 걸쳐 정치망에 입망하는 어군의 입망상태, 어군의 행동 및 정치망 어구의 변화를 조사하여, 원격어군탐지기의 실용성에 대해서 평가, 분석한 결과는 다음과 같다. 1. 정치망내의 해상이 동국에서 탐지한 어군탐지기의 기록과 그것을 원격으로 전송한 육상고정국의 어군기록은 잘 일치하였다. 2. 비탈그물과 원통의 밑판그물은 불규칙적인 변동을 하였으며, 그 지속시간은 원통그물쪽이 더 길었고, 그 변동폭은 각각 약 3.6m와 6.0m였다. 3. 헛통입구와 비탈그물에서 어군의 주간에 약 5~7m 수층으로 입망하였고, 야간에는 전수층으로 분산되어 입망하였으며, 주간보다 야간에 더 많이 입망하였으나 새벽에는 입망어군이 매우 적었다. 4. 원통에서의 어군은 주간에는 그물의 아래쪽 수심 약 8m 수층에 분포하였으며, 야간에는 부상하여 전수층에 분산하여 분포하였고, 새벽에는 밀집된 군을 형성하는 경향을 나타내었다. 5. 조사 당시 정치망에 어획된 어종은 약 20종으로서, 총어획량은 약 500kg이었는 데, 그 중에서 멸치의 어획이 가장 많았다. 본 실험의 결과로 시험제작한 원격어군탐지기는 정치망에 입망하는 어군의 행동이나 분포특성에 대한 정보를 파악하는 데 매우 유효하게 활용할 수 있음이 확인되었다
해상에서 어군의 행동과 분포상태를 탐지하여 그 정보를 원격으로 전송하기 위한 원격어군탐지기를 시험제작하고, 이들을 이용하여 서해의 고군산군도 연안에서 1994년 8월 8일, 18일~19일 및 9월 8~9일에 낭장망에 입망하는 어군의 유영층과 그 어획변동 등을 조사하고, 원격어군탐지기의 실용성을 평가하여 분석, 고찰한 결과는 다음과 같다. 1. 어획어종은 12종이었으며, 멸치(Engraulis japonica), 꼴뚜기(Loligo beka), 밴댕이(Harengula zunasi) 등이 전 어획량의 95%이상을 차지하였다. 2. 해상이 동국에서 탐지한 어군탐지기의 기록과 그것을 원격으로 전송한 선상고정국의 어군기록은 매우 잘 일치하였다. 3. 멸치는 유속이 0.6kt 이하로서 유속변화가 적은 경우에 어획이 많았으며, 유속이 0.6kt이상인 때에는 적어지는 경향을 나타내었다. 4. 어군의 유영층은 유속이 1kt이하에서 얕아지는 경향이 있었으며, 유속이 1kt이상이고 유속변화가 커지면 유영층에 큰 변동이 없으며, 이때 평균깊이는 약 4m였다. 5. 1회 조업당 어획량은 10~30 kg이었으며, 유향과 어구의 부설방향이 일치하지 않거나 유속이 너무 강해지면 어획이 적음을 알 수 있었다. 이상의 결과와 같이 본 연구에서 시험제작한 원격어군탐지기는 낭장망어업에서 어군의 행동과 분포에 관한 어업정보를 파악하는데 유효하게 사용할 수 있음이 확인되었다.
Working depth of the model net was determined by using of the same experimental tank and the same model net that used in the forwarded report in a series studies. The depth of the net which indicates the depth of the head rope from the water surface, was determined by the photographs taken in front of the net mouth with the combination of towing velocity, warp length and distance between paired boats. The results obtained can be summarized as follows: 1. Working depth of model nets A and B was varied in the range of 0.09~1.66〈TEA〉m,and 0.04~1.34〈TEA〉〈/TEX〉m〈/TEX〉(which can be converted into 2.7~40.2〈TEA〉mand 1.2~49.8〈TEA〉〈/TEX〉m〈/TEX〉in the full-scale net) respectively, and the depth of model net A was slightly deeper than the depth of the model net B. 2. Working depth (〈TEA〉D,which is appendixed m for the model net, f for the full-scale net, A and B for the types of the model nets) can be expressed as the function of towing velocity〈TEA〉〈/TEX〉Vt〈/TEX〉, as in the model net(〈TEA〉Vt=〈TEA〉〈/TEX〉m〈/TEX〉/〈TEA〉sec) 〈TEA〉〈/TEX〉DmA〈/TEX〉=(-1.99+0.65〈TEA〉Lw) 〈TEA〉〈/TEX〉e-1.72Vt〈/TEX〉 〈TEA〉DmA]=(-1.91+1.04 〈TEA〉Lw) 〈TEA〉〈/TEX〉e2.88Vt〈/TEX〉 in the full-scale net(〈TEA〉Vt=〈TEA〉〈/TEX〉k〈/TEX〉'〈TEA〉〈/TEX〉t〈/TEX〉 〈TEA〉DfA=(-29.32+0.65〈TEA〉〈/TEX〉Lw〈/TEX〉)〈TEA〉e0.40 Vt 〈TEA〉〈/TEX〉DfB〈/TEX〉=(-57.60+1.04〈TEA〉Lw)〈TEA〉〈/TEX〉e-0.67 Vt〈/TEX〉 3. Working depth 9〈TEA〉D appendixes are as same as the former) can be expressed as the function of warp length〈TEA〉〈/TEX〉Lw〈/TEX〉) in the model net, and can be converted into full-scale net as in the model net (〈TEA〉Vt=〈TEA〉〈/TEX〉m〈/TEX〉/〈TEA〉sec) 〈TEA〉〈/TEX〉DmA〈/TEX〉=-0.99 〈TEA〉e-1.42Vt+0.67〈TEA〉〈/TEX〉e-1359Vt〈/TEX〉〈TEA〉Lw 〈TEA〉〈/TEX〉DmB〈/TEX〉=-.258〈TEA〉e-3.77Vt+1.16〈TEA〉〈/TEX〉e-3.15Vt〈/TEX〉 〈TEA〉Lw, in the full-scale net(〈TEA〉〈/TEX〉Vt〈/TEX〉=k't) 〈TEA〉DfA=-29.28〈TEA〉〈/TEX〉e-0.32Vt〈/TEX〉+0.67〈TEA〉e-0.37Vt〈TEA〉Lw 〈TEA〉〈/TEX〉DfB〈/TEX〉=-69.10〈TEA〉〈/TEX〉e-0.81Vt〈/TEX〉+1.16〈TEA〉e-0.72Vt〈TEA〉〈/TEX〉Lw〈/TEX〉. 4. Working depth was gradually shallowed according to the increase of the distance between paired boats.
A model experiment on the pair midwater trawl net applicable to 800 PS class Korean pair bottom trawlers was carried out in the special-prepared experimental thank. the tank was prepared as a reverse trapezoid shape in its vertical section by digging out flat soil. The dimension of the tank showed the 9.6 W×43.0 L(m) of the upper fringe and the 4.8 W×38.0 L(m) of the bottom with 3.0m in depth. The depth of water was maintained 2.7m during experiment. The model net was prepared based on the Tauti's similarity law of fishing gear in 1/30 scale considering the dimension of the experimental tank. Mouth performance of the model net during towing were determined by the photographs taken in front of the net mouth with the combinations of towing velocity, warp length and distance between paired boats. The results obtained can be summarized as follows: 1. Vertical opening of the model nets A and B was varied in the range of 0.18~0.88 m and 0.21~0.78 m (which can be converted into 5.4~26.4m and 6.3~23.4 m in the full-scale net) respectively, and was varied predominantly by towing speed. Vertical opening (H which is appendixed m for the model net. f for the full-scale net. A and B for the types of the model net) can be expressed as the function of towing velocity〈TEA〉Vtas in the model net 〈TEA〉〈/TEX〉Vt〈/TEX〉 : m/ sec)〈TEA〉HmA=1.67〈TEA〉〈/TEX〉e-1.65Vt〈/TEX〉 〈TEA〉HmB=1.15〈TEA〉〈/TEX〉e-1.13Vt〈/TEX〉, in the full-scale net (〈TEA〉Vt : k't) 〈TEA〉〈/TEX〉HfA〈/TEX〉=50.27〈TEA〉e-0.37Vt 〈TEA〉〈/TEX〉HfB〈/TEX〉=34.46〈TEA〉e-0.26Vt. 2. Horizontal opening of the model nets An and b was varied in the range of 1.03~1.54m and 1.04~1.55 m (which can be converted into 30.9~46.2 m and 31.2~46.5m in the full-scale net) respectively, and was varied predominantly by distance between paired boats. Horizontal opening (W, appendixes are as same as the former) an be expressed as the function of distance between paired boats 〈TEA〉〈/TEX〉Db〈/TEX〉as in the model net 〈TEA〉WmA=0.69+0.09〈TEA〉〈/TEX〉Db〈/TEX〉 〈TEA〉WmB=0.73+0.09〈TEA〉〈/TEX〉Db〈/TEX〉, in the full-scale net 〈TEA〉WfA=20.81+0.09〈TEA〉〈/TEX〉Db〈/TEX〉 〈TEA〉WfB=22.11+0.09〈TEA〉〈/TEX〉Db〈/TEX〉 3. Net opening area of the model net A and B was varied in the range of 0.28~1.04 〈TEA〉m2 and 0.33~0.94〈TEA〉〈/TEX〉m2〈/TEX〉(which can be converted into 252~936〈TEA〉m2 and 297~846〈TEA〉〈/TEX〉m2〈/TEX〉 in the full-scale net) respectively, and was varied predominantly by towing velocity. Net opening area (〈TEA〉S, appendixes are as same as the former) van be expressed as the function of towing velocity〈TEA〉〈/TEX〉Vt〈/TEX〉 as in the model net 〈TEA〉vt : m/sec) 〈TEA〉〈/TEX〉SMa〈/TEX〉=2.01〈TEA〉e-1.54VT 〈TEA〉〈/TEX〉SmA〈/TEX〉=1.40〈TEA〉e-1.65Vt, in the full-scale net (〈TEA〉Vt : k't) 〈TEA〉〈/TEX〉SfA〈/TEX〉=1.807〈TEA〉〈/TEX〉e-0.35Vt〈/TEX〉 〈TEA〉SfA=1.265〈TEA〉〈/TEX〉e-0.24Vt〈/TEX〉. 4. Filtering volume of the model nets A and B was varied in the range of 0.32~0.55 〈TEA〉m3 and 0.37~0.55〈TEA〉〈/TEX〉m3〈/TEX〉(which can be converted into 8.640~14.850 〈TEA〉m3 and 9.990~14.850〈TEA〉〈/TEX〉m3〈/TEX〉in the full~scale net) respectively, and was predominantly varied by towing speed. filteri..
Exercise physiology of fish was studied by means of Electro-cardio-gram(ECG) technique with wired electrode system. Effects of swimming activity on the heart rate change for carp Cyprinus carpio was observed and analysed under swimming speeds among 1~3 Body Length/s and swimming durations of 10 and 60 minutes in the flume tank. The heart rate increase during swimming activity was observed in higher speed and longer duration conditions. The exercise effect on the heart rate continued even after fish stopped swimming. The time for recovery after exercise was tended to be elongated with the higher exercise condition
여수 연안 정치망 어장의 주변 해역을 중심으로 1990년 4월부터 11월까지 매월 채집해서 분석한 식물플랑크톤의 분포량과 여수수협 위판장으로부터 구한 어획량 자료등을 이용하여 여수 연안 정치망 어장의 환경요인인 식물플랑크톤의 분포량과 어획량 변동과의 관계를 분석 정리한 결과를 요약하면 다음과 같다. 1) 식물성 플랑크톤의 출현량은 춘계와 추계보다 하계에 최대가 되고, 특히 육수의 유입이 많은 여수만 중 돌산연안 수역 분포량이 많고, 소리도와 세존도부근의 식물성 플랑크톤 분포량은 내만수의 확장 경향을 추정하는데 유익하게 이용될 수 있다. 2) 여수 연안 정치망에 어획되는 주요 어종의 어획량은 삼치, 갈치, 고등어, 정어리, 멸치, 전갱이 및 방어의 순이고, 어획되는 시기는 정어리와 멸치가 4~6월, 전갱이, 갈치 및 고등어는 6~10월이 였으며, 삼치는 전 어기에 걸쳐 어획되었다. 3) 여수 연안 정치망 어장의 어획량은 식물성 플랑크톤 출현량과 상관 관계가 있고, 이들 식물성 플랑크톤량은 하계 육수의 영향을 많이 받는 내만수에 최대의 출현량을 보인다. 또, 이 어장의 어획량은 하계에 많으므로 여수 연안 정치망 어장은 육수의 유입에 의해 풍부한 영양염류를 공급받는 내만수내의 이료생물의 생산력이 어획량을 좌우하는 어장의 중요한 환경요인이 될 수 있다
정치망 내외에 있어서 정어리 대형군의 행동조사는 1992년 1월 29일부터 2월 22일 사이에 일본국 석천현 칠미시 연안 정치망어장에서 소나를 이용하여 실시하였고, 소나의 영상기록을 해석하여 얻어진 결과를 요약하면 다음과 같다. 1. 정치망 바깥쪽 부근에서 이동중인 어군의 행동양식은 어군의 각 위치에 따라 다른 행동이 관찰되었고, 부분적인 확대와 축소를 보이면서 어군전체가 이동하였다. 2. 헛통입구로 들어간 어군은 등망방향, 헛통의 등방향, 헛통의 옆줄방향으로 분산되었으며, 그후 헛통의 등방향, 헛통의 옆줄방향, 입구방향의 어군은 등망쪽으로 조밀하게 이동하는 행동양식을 취하면서 입구로부터 외등망까지 이동하였다. 3. 정치망의 안쪽과 바깥쪽에 있어서 어군의 주연부가 확대하는 경우, 최대 이동속도는 바깥쪽에서 277cm/sec, 안쪽에서 176cm/sec이었다.
대형정치망내에 있어서 어군의 행동 조사는 1992년 1월 29일부터 2월 22일 사이에 일본국 석천현 연안 정치망 어장에서 실시하고, 정치망어구의 어획기능에 관해서 해석, 검토하였으며, 얻어진 결과를 요약하면 다음과 같다. 1. 헛통에 출현한 어군수는 17~18시의 일몰시에 가장 많았고, 그후 급격히 감소하는 경향이었다, 이것으로 보아, 헛통에 있어서 어군의 체류시간은 짧고, 비교적 빠르게 원통에 입망했던가 혹은 헛통의 입구로부터 도피했다고 생각된다. 2. 망내에 입망한 정어리소형군의 행동은 측망에 평행한 직선적인 주복이동이 많고, 등망의 부근에서는 방향을 전환하여 헛통의 옆줄에 향하는 행동이 관찰되었다. 3. 망내에 입망한 정어리소형군의 이동속도는 25cm/sec가 최빈치이고, 최대 이동속도는 80cm/sec 이었다.
We have prepared superconducting Bi-Pb-Sr-Ca.Cu-O thin films by RF magnetron sputtering technique, on heated MgO(100) substrates. Sputtering was carried out in a mixture of argon and oxygen(10%) and the pressure was maintained at 5 mTorr during deposition. The substrate temperature was maintained 400℃ during deposition. The films sputtered were amorphous and insulating. All the films became superconducting by annealing, The films annealed at 880℃ for 30 minutes in air showed high-Tc phase with zero resistivity of 93K. These results indicate that the growth of the high-Tc phase is promoted by the presence of Pb at annealing temperature.
From the results of model tests, statistical regression analysis for EHP estimation based on hull form parameters is adopted in this study. From this result, the method for estimation of EHP and optimization of hull form parameters at the initial design stage of fishing boats is developed. This method is applied to two standard fishing boats with chine lines. The EHP s are estimated and compared to experimental results. From the optimization of four principal hull form parameters of these fishing boats, approximately 19% of resistance reduction at the design speed is achieved and thus certifies that this method can be used efficiently for the initial design of hull forms of fishing boats.
This paper presents a dynamic compensation methodology for robust trajectory tracking control of uncertain robot manipulators. To improve tracking performance of the system, a full model-based feedforward compensation with continuous VS-type robust control is developed in this paper(i.e,. robust decentralized adaptive control scheme). Since possible bounds of uncertainties are unknown, the adaptive bounds of the robust control is used to directly estimate the uncertainty bounds(instead of estimating manipulator parameters as in centralized adaptive control0. The global stability and robustness issues of the proposed control algorithm have been investigated extensively and rigorously via a Lyapunov method. The presented control algorithm guarantees that all system responses are uniformly ultimately bounded. Thus, it is shown that the control system is evaluated to be highly robust with respect to significant uncertainties.
In 1980 s to 1990 s the marine propulsion diesel engines have been developed into lower speed and longer stroke for the enegy saving (small S.F.O.C). As these new trends the conventional mechanical-hydraulic governors were not adapted to the new requirements and the digital governors have been adopted in the marine use. The digital governors usually use the control algorithms such as the PID control, optimal control, adaptive control and etc. While the engine has delay time and parameter variations these control algorithms have difficulty in considering the stability and the robustness for the model uncertainty. In this study, the H∞ controller design method are applied in order to design the feedback controller K(s) to the speed control of the low speed marine diesel engine, and the two-degree-of-freedom control system is constituted with H∞controller. By comparison of responses of the two-degree-of-freedom control system under the delay time and parameter variations is confirmed.
Recently, with the rapid development in the industries such as an iron mill and chemical plants, there is enlarged by the use of the piping. Sepecially, the piping connected with a fluid, if it is increase the speed of running fluid, ought to generate cavitation phenomenon with unbalanced pressure. So, the cavitation phenomenon cause serious damage of the piping, because it generate erosion and corrosion in the piping. In this study, the steel pipe piping water (SPPW) and SPPW on weldment were tested by using of cavitation-erosion test apparatus with nozzle and were investigated under the marine environment of liquid. (specific resistance : 25 Omega. cm) The main results obtained are as follows : 1) The total weight loss and weight loss rate of affected zone of weldment by corrosion-erosion in the sea water are more increased than that of base metal. 2) The electrode potential by corrosion-erosion in the sea water becomes less noble than that of base metal, and current density is more increased. 3) As time goes by, the total weight loss and weight loss rate by cavitation erosion-corrosion in air-liquid 2 phase flow become more increased then those in only liquid solution. but these values turn to be decreased.
The new course distances of a ship are one of the important factors of the safety handling as the indices to indicate directly her abilities of course alteration. Recently, International Maritime Organization (IMO) exhorts that all vessels should use maneuvering booklets in which are drawn the curves of new course distances obtained from the test of measuring them and noted other maneuvering performance standard in various navigation conditions. This paper describes the method to calculate many new course distances for many rudder angles by turning circle test without observation or using other calculating methods. The main results are as follows: 1) The mean difference of the distances between two new course distances by the turning circle test and heading test of the experimental ship was about 7.7% vaules of the ones by the heading test. when her altering angles were 48˚, 63˚and 70˚, using the rudder angle of 35˚ . These new course distances were therefore found to be small in difference of those. 2) The mean difference of the distance between two new course distances by the turning circle test and the maneuvering indices of the experimental ship was about 4.5% values of the ones by the maneuvering indices, when her altering angles were 48˚, 63˚and 70˚, using the rudder angle of 35˚, these new course distances were therefore found to be small in difference of those. 3) The mean difference of the distance between two new course distances by the turning circle test and the observation of the experimental ship was about 6.1% values of the ones by the observation, when her altering angles were 48˚, 63˚and 70˚, using the rudder angle of 35˚. These new course distances were therefore found to be small in difference of those. 4) It is confirmed that many new course distances for many angles can be calculated easily by using the method of ship's simple turning circle test, without observation or using the maneuvering indices and heading test method. 5) It is considered to be helpful for the safety of ship handling to draw curves of new course distances by turning circle test and Φ4 - Φ2 by heading test, and utilize them at sea.
Catching performance of a mechanized pollock longline system compared with traditional one were examined in order to evaluate the practicality during two cruises in the Sokcho area. Mechanized longline system consists of random baiter, bait cutting machine, storage rails, and line hauler. Baiting efficiency of random baiter was 90-95% with 4-5kt shooting speed. Catching performance of the first experiment, salted sand lance only used as a bait. shows no significant difference between mechanized operation with use fresh sand lance as a bait caught significantly more pollock than traditional one with use salted sand lance (P<0.016). Improved catch rates were about 2 times. As soak time goes on, relative catching efficiency shows a steady increase up to 6~7 hours and thereafter gradually decrease.
This paper describes about the behavior of the Striped mullet (Mugil cephalus) in the setnet by telemetry techniques. The telemetry system consists of a pinger of 50KHz, three omni-directional hydrophones and ultrasonic receivers, a single board computer for the signal processing, two RF transceivers for the data comunication and a personnel computer. The fish tagged the pinger was tracked by the LBL method, and its location was calculated by the hyperbolic method. The fish escaped from sea surface to 7m deep right after release and had been swum near the sea surface after 30 minutes being released. Also, in horizontal movements, the fish stayed long time around the enterance of the square net in setnet, and showed the escaping behavior repeatly. The average speed of the fish was about 0.41m/sec(1.1 times of the body length)
This paper describes about the behavior of the lseraeli carp (Cyprinus cartio. body length 43cm) and the Red seabream (Chrysophrys major. body length 35cm) aquacultured by telemetry techniques. The telemetry system consists of a pinger of 50kHz, three omni-directional hydrophones and ultrasonic receivers, a single board computer for the signal processing, two RF transceivers for the data communication, and a personnel computer. Those fish tagged the pingers were tracked by the LBL method, and its location was calculated by the hyperbolic method. The average speed of the lsraeli carp was about 1.0 times of the body length in a farming water tank (24×24×1m), and the Red seabream 1.3 times of the body length in a farming raft (10×10×5m). A variation of the speed of the lsraeli carp was higher than the other one.