간행물

수산해양기술연구 KCI 등재 Journal of the Korean Society of Fisheries and Ocean Technology 韓國漁業技術學會誌

권호리스트/논문검색
이 간행물 논문 검색

권호

48권 1호 (2012년 2월) 10

1.
2012.02 구독 인증기관 무료, 개인회원 유료
For the optimal design of a shrimp pot to control the catch size and to reduce catch the small size shrimp, tank experiments were carried out to study the pot stability under water. Tank experiments were carried out to measure the drag with 4 kinds of model pots that have 50% selection on the individual of 25mm carapace length. The drag of each pot was measured every 10 times with changing the current speeds from 0.1m/s to 0.7m/s in 0.1m/s intervals and the pot attack angle from 0˚ to 90˚ in 15˚ interval in a flume tank. The relation between the current speed and drag was presented. The stability of pot was estimated using the drag data and the friction data of Kim et al. (2008b). The results showed that, the drag was shown lower as small as the projected area of pot depending on the current speeds and angles. The model pots were showed to slide on the seabed in case of rock at the current speeds 0.35-0.38m/s and the possibility of turn over at the current speeds 0.77-0.89m/s. In conclusion, the stability of a shrimp pot showed more stable as the pot of the lower the height and the smaller projected area on current.
4,000원
2.
2012.02 구독 인증기관 무료, 개인회원 유료
The mesh selectivity of a drift net for yellow croaker (Larimichthys polyactis) was examined in field experiments with six different net mesh size (40, 45, 50, 55, 60 and 65mm) from April to December, 2008 in the coastal areas of Jeollanam-do in Korea. The total catch of 6,748 consisted of yellow croaker (n=6,310; 89.1% of total catch), common mackerel (n=158; 5.6%) and other species (n=280; 9.6%). The selectivity curve for yellow croaker was fit by the models of selectivity curve in SELECT method. The optimal mesh size for 50% retention for minimum landing size (191mm) of yellow croaker was estimated as 49.6mm-51mm by selectivity curves. And the bi-normal model for the selectivity curve was found to fit the data best.
4,000원
3.
2012.02 구독 인증기관 무료, 개인회원 유료
The monofilament with 0.304mm of diameter was produced using a polybutylene succinate (PBS) resin, and a gill net was made by it. We investigated the impact of heat setting temperature on the mechanical properties, knot state and height of gill net. Heat treatment was carried out using the high pressure steam machine for 20 minutes at temperature of 55℃, 60℃, 70℃ and 75℃. Before heat treatment, the strength and elongation of PBS monofilament were estimated to be 48.1kg/mm2, 23.8% at unknot, 37.6kg/mm2, 18.8% at single knot, 26.6kg/mm2, 22.9% at double knot in dry condition, respectively. The strength and elongation of PBS monofilament with double knot were decreased as heat setting temperature increased, and the decreasing rate of strength was showed to be higher than that of elongation. It was not found any differences in strength and elongation of PBS monofilament yarn with double knot at the 65℃ and 70℃ of heat setting temperature by 5% significance of T-test, but there was a significant difference at the 70℃ and 75℃ of heat setting temperature. The net's height and length from leg to leg appeared no differences at the 70℃ and 75℃ of heat setting temperature. In results, it was investigated that the PBS monofilament gill net with the maximized physical properties could be manufactured at 70℃ of heat setting temperature using a high pressure steam machine for 20 minutes.
4,000원
4.
2012.02 구독 인증기관 무료, 개인회원 유료
Currently, environment-friendly and sustainable fisheries are one of the major issues among fisheries authorities. A variety of alternative management policies and projects are going on to enhance fisheries management systems and fishery resources such as a TAC management program and a VDS (Vessel Day Scheme) management scheme for distant water fishing nations in Western and Central Pacific Fisheries Commission (WCPFC) convention area. These kinds of efforts among fisheries management authorities are aimed at limiting fishing capacity or fishing power. In terms of fisheries management, Fishing capacity and fishing power have increased the importance of the impact on a fishery and level of the resources. Increased fishing capacity and fishing power have caused not only depletion of fisheries resource, but also additional fishing cost. therefore, there is a clear need for authorities to manage fishing capacity and fishing power. It is also help ensure the conservation and sustainability of the fishery resources. Because of lack of data, absolute fishing power is difficulty to measure. The notion of relative fishing power is frequently used. In this study, relative fishing power was assessed using Mastuda (1991) method for fishing power index. The raw data for assessment was based on fishermen's logbook data from sampled fishing vessels in coastal snow crab gillnet fishery. Data Envelopment Analysis (DEA) method was used to assess fishing capacity. DEA is a linear programming methodology to measure the efficiency of a set of entities called Decision-Making Units (DMUs). It was recommended by FAO for assessing capacity in fisheries.
4,200원
5.
2012.02 구독 인증기관 무료, 개인회원 유료
This study aims to analyze the performance of a submersible fish cage which was designed for developing an economical cage system can be applied in korean aquaculture environment easily. To analyze the performance of the designed cage a model test was carried out. In the test, inclination changes of the upper frame and mooring tensions of model cage were measured during the submerging and surfacing motion in still water and wave condition (period: 2s, wave height: 0.1, 0.2, 0.3m). As a result, in the still water condition the model cage kept horizontal balance and inclination degree of the upper frame was about 1˚. In the wave condition, the model cage showed bilateral symmetric up-and-down motion but the average inclination degree of the upper frame was about 0˚. When the model cage reached at a depth of 1m, the up-and-down motion of the cage was decreased by 12% compared with that of at the surface (period 2s, height 0.3m). In the same wave condition, the maximum and average line tension under the bottom position were about 8% and 11% respectively compared with that of at surface.
4,200원
6.
2012.02 구독 인증기관 무료, 개인회원 유료
As a basic study to improve hooking ability of long line fishing gear, which is widely used around Jeju-do coast, the researcher performed hooking experiment of parrot fish by manufacturing and installing 7 kinds of model long line fishing gears, whose thickness of branch line are different and 8 kinds of model long line fishing gear, whose length of branch line are different, in indoor circular aquarium, which is installed for the model experiment of thickness and length of branch line that are various by fishing implement and improper. The hooking rate depending on thickness and length of branch line was calculated and the effect of thickness and length of branch line on hooking rate was analyzed. Its results are as follows. When branch line was thin and long, high hooking rate appeared. In the scope of value setting, the relationship between thickness (Bt) of branch line and total hooking rate (Thr) can be shown as following formula as. In the scope of value setting, the relationship between length (Bt) of branch line and total hooking rate (Bt) can be shown as Thr=-20.83Bt+26.04. Through Pearson correlation analysis, the coefficient of correlation between thickness of branch line and hooking rate was -0.718. Therefore it showed significance in 0.01 significance level. Through Pearson correlation analysis, the coefficient of correlation between length of branch line and hooking rate was 0.431. Therefore it showed significance in 0.01 significance level.
4,000원
7.
2012.02 구독 인증기관 무료, 개인회원 유료
In order to elucidate the mechanism of fishing condition variation of anchovy in the set net fisheries of Anggang Bay, the monthly catch of anchovy was analyzed and examined based on the data acquired from 2006 to 2010 in 13 different fishing grounds. Anchovy consistently appeared from April to December and reached the production of 840 to 1,424 t (average : 1,228 t), with a big annual variation. However, anchovy production in this area accounts for approximately 75% of the production by set net in Anggang Bay whereas it holds 6.8% of the nationwide production (=18,034 t) by set net. The school of anchovy starts to appear in April at the west mouth of the bay and move north-eastward. Afterward, having three of clockwise turns in the middle of the bay, they scatter to swim into the deep place of the bay and finally go out to turn back to their coming way. These behaviors of anchovy are likely related to thermal fronts as well as distributions of food. The production of anchovy (y, kg) relied greatly on frequencies of effective northeasterly (x1) or northwesterly (x2) wind (≤3.5m/s) which blow between April and June. Their relationships are as follows: y=1086.27+21.499x1-15.16x2 (r=0.901). Consequently, we concluded that the northeasterly wind, which appears in the breeding season of spring, played a role to retard the movement of anchovy school to the eastern sea, while the northwesterly wind inhibits the invasion of anchovy school into the bay.
4,500원
8.
2012.02 구독 인증기관 무료, 개인회원 유료
Using artificial neural network (ANN) technique, auction prices for common mackerel were forecasted with the daily total sale and auction price data at the Busan Cooperative Fish Market before introducing Total Allowable Catch (TAC) system, when catch data had no limit in Korea. Virtual input data produced from actual data were used to improve the accuracy of prediction and the suitable neural network was induced for the prediction. We tested 35 networks to be retained 10, and found good performance network with regression ratio of 0.904 and determination coefficient of 0.695. There were significant variations between training and verification errors in this network. Ideally, it should require more training cases to avoid over-learning, which leads to improve performance and makes the results more reliable. And the precision of prediction was improved when environmental factors including physical and biological variables were added. This network for prediction of price and catch was considered to be applicable for other fishes.
4,000원
9.
2012.02 구독 인증기관 무료, 개인회원 유료
Four different buildings having various wall construction are analyzed for the effect of wall mass on the thermal performance and inside building air and wall temperature transient and also for calculating the energy consumption load. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one-dimensional, linear, partial differential equations is obtained using the Laplace transform method, Bromwich and modified Bromwich contour method. A simple dynamic model using steady state analysis as simplified methods is developed and results of energy consumption loads are compared with results obtained using the analytical solution. Typical Meteorological Year data are processed to yield hourly average monthly values. This study is conducted using weather data from two different locations in Korea: Daegu having severe weather in summer and winter and Jeju having mild weather almost all year round. There is a significant wall mass effect on the thermal performance of a building in mild weather condition. Buildings of heavyweight construction with insulation show the highest comfort level in mild weather condition. A proportional controller provides the higher comfort level in comparison with buildings using on-off controller. The steady state analysis gives an accurate estimate of energy load for all types of construction. Finally, it appears that both mass and wall insulation are important factors in the thermal performance of buildings, but their relative merits should be decided in each building by a strict analysis of the building layout, weather conditions and site condition.
4,000원
10.
2012.02 구독 인증기관 무료, 개인회원 유료
This study is aimed to utilize a basic data for setting up an allowable air noise with IMO standard in accommodation and working areas of 24m longer fishing vessels. The air noise in accommodation and working areas of 300 tons class squid-jigger were evaluated and the levels were compared to the allowable levels of IMO. The results indicated that the maximum range of noise levels was estimated to be between 54.8dB (A) and 83.2dB, and the correlation between the distance from the main engine to measuring point and the maximum noise level of each point was shown to be y=-13.8log (r)+92.91 (r2=0.821). In addition, except the case of making an accommodation area near to the engine room in 24m longer jigging vessels, it was evaluated that the accommodation noise regulation of 1,600 tons international voyage vessels with 60dB (A) or an improved noise level with 65dB (A) could be properly applied.
4,000원