Fuel consumption in fisheries is a primary concern due to environmental effects and costs to fishermen. Much research has been carried out to reduce the fuel consumption related to fishing operations. The fuel consumption of fishing gear in fishing operation is generally related to hydrodynamic resistance on the gear. This research is to propose a low drag generated midwater trawl in terms of the gear design improvement using simulations. The results from the simulation were verified with results that mirrored the model experiments. From the results, the resistance force of the proposed gear decreased to 29% compared to that of the current gear. Furthermore, the gear performance also improved with increased gear mouth compared to the current one. Therefore, the proposed gear will be helpful to reduce the greenhouse gases from fishing operation. It will also contribute to the fishing industry by saving fuel.

This study carried out and analyzed survey data on captains and mates of Korean coastal large trawlers in order to examine factors affecting body abnormalities and fatigue on bridge teams from work and environment at bridges of trawlers. The summarized result may be summed up as follows: multiple regression analysis with body pain and fatigue as dependent variables yields t-values of –2.559 (p<0.05) and –3.928 (p<0.05) respectively. From the result, environment at bridges (views, spaces and exhaust) were negative factors in affecting bridge workers’ pain and fatigue. Thus, it is determined to secure available spaces to improve the workers’ views through windows in front of, besides and rear bridge and create more pleasant atmospheric environment at bridge.

The aim of this research was to the experimental data using statistical and spectral analyzing method to get the motion reponses of a stern trawler in operation states such as drifting, sailing and trawling according to the wave height. In drifting, the significant and the maximum valuer of roll in beam sea increased according to the wave height, but those of pitch decreased. The response and the period of peak of roll in beam sea were increased, but those of pitch decreased. In navigation, the significant and maximum values of roll increased remarkably according to the wave height, but those of pitch changed a little. The response of roll was highest in quartering sea, beam sea and then following sea, but those of pitch was highest in bow sea, head sea and then beam sea in the order of all wave heights. The period of peak of roll due to the wave height and the wave direction changed from 3.8 to 9.9 seconds, and those of pitch changed from 3.3 to 10.4 seconds. In trawling, the significant and maximum values of roll increased a little according to the wave height, but those of pitch increased significantly. The response of roll was highest in beam sea, bow sea and then quartering sea, but those of pitch was highest in head sea, following sea, and then beam sea in the order. The period of peak of roll due to the wave height and the direction changed from 6.6 to 10.9 seconds, and those of pitch changed from 6.7 to 11.2 seconds.

The trawl fishery is an important fishery accounting for around 30.0% of adjacent water fishery production in Korea, and the commercial fishing is associated with high rate of fatal and non-fatal occupational injury. The hazard analysis for the fishermen's safety of offshore trawler was conducted to serve as basic data for improving the healthy and safe working environment of fishermen using fishermen's occupational accidents of the national federation of fisheries cooperatives (NFFC) from 2012 to 2014 (n=464). As a result, the occupational accident occurrence rate of large powered trawl fishery was 241.4‰ in east sea trawl fishery, 6.9 times the rate of that. In addition, death and missing rate was found to have very serious level management to 97.7‱ in east sea trawl fishery of death at 6.2 times. The accident occurred in 91.7 to 100.0% was happened at sea. The slipping, others and struck by object and son on occurred more frequently in order in the frequency of accident occurrence pattern. However, the occurrence rate of death and missing did not match the frequency of accident pattern. In other words, slipping occurred more frequently while death and missing risk was not high. The fall in the waters was low while death and missing risk was high. The results are expected to help identify and assess safety hazard occurred in offshore trawlers.

This study attempted to help determine Korean fishery policies by proposing improvement plans after examining the current regulations, fishing vessels, fishing gear and fishing methods of the middle sized trawl fishery in the East Sea for targeting only squid. In general, the size, engine horse power, and net length of the middle sized trawlers are between 50 and 60 GT, 1,200 and 1,600 PS, and approximately 165 m with four seamed trawl nets, respectively. While a jigging vessel attracted squids using lights, the trawler approached a jigging vessel. The trawler let the jigging vessel know its decision for fishing, and then jigging vessel rolled up jigs. The net of the trawler was casted at 45 degrees between the bow and the stern of the jigging vessel. Once the trawler towed close to the stern of the jigging vessel upon its passing of the jigging vessel, the bow of the trawler turned 45 degrees left again. Then, squid aggregations were entered into the net. When the cod end was passed a light vessel, the trawler hoisted the net up to the otter board. Then the trawler turned 180 degrees. It repeated three to five times of fishing operations as the previous method. We recommend that the regulations allow nineteen side trawlers to catch like stern trawler, as well as the cooperative trawler and jigging vessel operations.

Annual and monthly pollock catches, CPUE and fishing grounds in the high seas of Bering Sea between 1984 and 1992 were analyzed for centroid distribution and bivariate ellipses of trawlers of South Korea, Japan, Poland and China. The catch amount differed by country as 56.1%, 21.7%, 20.4% and 1.8% were caught by Japan, Korea, Poland and China respectively. Japan recorded the highest mean CPUE at 5.7 ton/hour while it was 4.3 ton/hour for Poland, 3.9 ton/hour for Korea and 2.4 ton/hour for China. Cumulative catch varied by month, with the minimum of 137,000 ton in March and the maximum of 848,000 ton in December. Monthly mean of CPUE was the lowest in February (2.0 ton/hour) and the highest in November (6.3 ton/hour). The centroid distribution of monthly fishing ground was located at a southern spot (56° 05'N, 178° 55'E) in January, and it moved anti-clockwise toward 56° 37'N, 178° 24'E in December. Fishing grounds were scattered more by the east-west direction than by the south-north direction. The fishing grounds were similar for Korean, Japanese and Polish trawlers, but Chinese trawlers that fished only from July to December showed distinctively different fishing grounds from the others.

Celastrol은 미역줄나무의 뿌리에서 얻은 추출물로 오래전부터 관절염 및 자가면역 같은 염증반응 질병들을 치료하기 위하여 쓰여져 왔다. 이외에도 많은 연구들에서 celastrol이 신경보호, 항산화 및 알츠하이머 치료에 사용될 수 있으며 특히, 암 치료에 효과적이라고 밝혀 졌다(Table 1). 따라서 많은 연구자들이 생리학적, 생화학적 및 면역학적 관점에서 celastrol의 항암효과를 규명하고자 노력을 기울이고 있으며, 다양한 관점에서 신호전달체계를 조절한다는 사실을 밝혀냈다(Fig. 1). 특히, celastrol은 NF-κB 를 억제함으로서 암의 발달 및 전이를 저해함을 물론, 암의 치료에 동반되는 면역 반응을 조절 할 수 있다(Fig. 2). 또한 세포사멸과 관계된 유전자들을 활성화 시키고, 항세포사멸 유전자들을 억제시킴으로서 세포 주기를 조절한다. 유전자 조절 외에도 heat shock protein과 같은 단백질의 변조와 자가소화작용(autophagy)를 유도한다. 이처럼 celastrol의 다양한 효과는 암의 성공적 치료에 한발 더 가까워지게 만든다. 이외에도 celastrol의 항 비만 효과가 알려지면서 향후 비만 및 비만과 연계된 암 환자들이 가질 수 있는 부작용, 오남용 및 비용절감 측면에서 좋은 결과를 나타낼 것이라 예상 된다. Celastrol의 다양한 기작이 밝혀짐에도 불구 하고 직접적인 결합 부위에 대한 연구 결과는 아직 없으며, 임상적용 하기에 앞서 다양한 동물모델 in vivo 실험이 필요하다. 또한 임상치료 시도에 있어 안전성을 확보 하기 위해서는 celastrol의 단기간 및 장기간의 효과에 대한 깊은 연구가 요구된다.

An acoustic and trawl pilot survey using a small vessel was conducted in Jinhae bay of the South Sea of South Korea on April 13~14, May 11~13 and June 8~10, 2015. During the survey, acoustic data was collected and bottom trawls were conducted at the same time. First, various noises were eliminated by using the Park method based on the Wang method(Wang et al., 2015; Park et al., 2015), the species compositions and catch rate from each bottom trawl were observed, and spatial distribution of fishery resources in the water column and their nautical area scattering coefficient (NASC) were investigated through acoustic data. During the entire survey period, 12 orders, 33 families and 41 species were caught. The most caught species in April, May and June were Okamejei kenojei, Zoarces gilli and Pholis nebulosa, respectively. Fish schools were observed near the line of net mouth height in April. Numerous weak scatters were presented on the echograms in May and June. Many fish schools appeared in between the water surface and 20 m deep in May. The NASC value from entire water columns was the lowest in April (35.9 m2/n･mile2) and highest in June (1541.3 m2/n･mile2).

To examine species composition, abundance and biomass of fishes in the northwestern East Sea of Russian EEZ, trawl survey were conducted at 31 sampling stations from 2006 to 2008. Also, trawl survey were conducted at 21 sampling stations in the southwestern East Sea of Korean EEZ from 2006 to 2008. A total of 67 fishes were collected in the northwestern East Sea of Russian EEZ, a total of 39 fishes were collected in the southwestern East Sea of Korean EEZ. Among them, a total of 53 fishes were collected in the northwestern East Sea of Russian EEZ only, and a total of 25 fishes were collected in the southwestern East Sea of Korean EEZ only. Mean abundance per area which caught by trawl survey in the northwestern East Sea ranged from a high of 116,478 inds./km2 in 2008 to a low of 19,737 inds./km2 in 2006. And mean abundance per area in the southwestern East Sea ranged from a high of 89,129 inds./km2 in 2006 to a low of 8,234 inds./km2 in 2008. Mean biomass per area which caught by trawl survey in the northwestern East Sea ranged from a high of 11,333 kg/km2 in 2008 to a low of 2,439 kg/km2 in 2006. And mean biomass per area in the southwestern East Sea ranged from a high of 6,273 kg/km2 in 2006 to a low of 1,062 kg/km2 in 2008. Cluster analysis, based on a Bray–Curtis similarity matrix of fourth root transformed data of number of species and individuals per area, showed division into three different groups by depth in the northwestern and southwestern East Sea.

The 1/5 scale–down model of the Bycatch Reduction Device (BRD) from an Argentinean demersal trawl was tested in a circulating water channel. The BRD is designed to help small Hake (merluza, merluccius hubbsi) to escape from a trawl. It is settled in front of a trawl codend, and is equipped with selection grids that help small fish to escape from the gear and guiding panels that help fish to meet with the grids. Bars of the grids are wires covered by the PVC and other parts of the BRD are made of net. When the velocity was less than 0.65 m/sec (2.81 Kont when translated to real towing speed) which is slow speed compared with real towing speed, position between an upper guiding panel and an upper selection grid were good to help small fish to escape. When the velocity was more than 0.8 m/sec (3.41 Knot when translated to real towing speed) which is similar to and faster than real towing speed, it was considered that small fish may have difficulties in escaping because the gap was not enough between an upper guiding panel and an upper selection grid. The lower selection grid was sat on the bottom of the tank without an angle due to the weight that it carries. Improvements were proposed to position the panels and the grids better.

The angle of attack of a cambered otter board in a bottom trawl was estimated using a three-dimensional semi-analytic treatment of a towing cable (warp) system that was applied to the field experiments of a bottom trawl obtained by the Scanmar system. The equilibrium condition of the horizontal component and vertical component of forces was used to the three forces acting on the otter board in the horizontal plane. Those forces were the force on the warp at the bracket, hydrodynamic lift and drag forces on the otter board and the force on the hand rope attached just behind the otter board. Also the equilibrium of moment about the front edge of the otter board was used to find out the angle of attack of the cambered otter board. When the warp length was 120m and 180m long and the towing speed was between 1.23 and 1.90 m/s, the estimated angle of attack of the cambered otter board was ranged between 26.1° and 29.6°, respectively, though the maximum lift force was at the angle of attack 22.6°. The angle of attack of the otter board was tended to increase weakly with the longer length of warp (180 m) at the same towing speed in the experiment.

Trawlers are divided into stern and side types by the method of shooting and hauling net, but the latter is difficult to find beside Korea. In East Sea of Korea, the side type used to be in early 2000’s, but it improved to stern type because of its inefficient operating method. The aims of this paper is to make clear the stability of the side trawler in the East Sea, and then confirm whether it satisfy the IMO rule or not, the degree of the transverse inclining angle of the ship when hauling net at hull side. In results, the stability of the ship in initial inclining range satisfied the IMO rule and the domestic rule, but not satisfied those rule in over the range. The limit load of the ship that was coincide with the angle of beam end in hauling net at side was about 26 tons, 18 tons in normal sea condition and storm warning condition respectively. The transverse inclining angles of the ship in hauling net were much higher from 3.3 to 5.5 times than the longitudinal inclining angle of the stern trawler, although those angles were slightly changed with depending on the loading and sea condition.