Since ships are exposed to noise and vibration for a long time in seas isolated from land, the stress of workers is high, requiring studies on the improvement of the problem. In addition, the health of crew members on fishing vessels, unlike commercial ships, carrying out fishing activities is closely related to fishing performance. However, considering that most of IMO's guidelines apply to merchant ships, provisions should be made for vibration in accommodation areas of fishing vessels. Accordingly, this study, applying the revised ISO 20283-5:2016 standard and through experiment, investigated the vibration characteristics of the accommodation area for each operating conditions of a 1000-ton trawler fishing vessel. Within the scope of the study and the full-ahead mode, the vibration was highest in the engine control room (4.17mm/s) while the acceptable standard was satisfied sufficiently in all conditions. Application of the merchant vessel vibration standard to fishing vessel is expected to improve the working environment of fishing vessel crew members.

In the actual sea, the additional resistance due to external force such as wind, current and wave is accompanied, and the required power is added in response to these resistance. Especially when the ship is sailing at low speed, the effects of wind and current have a great impact on the safe control of the ship. Likewise, it is thought that the effects of wind and current have a great impact on the trawl ship control since the towing speed of a bottom trawl ship is a low speed of 3 to 4 knots. If the reduce of ship speed and the increase of engine power due to the influence of wind and current can be identified, the safe towing power can be calculated based on a given engine output. Thus, the appropriate size of a fishing gear can be determined. In this study, a total of 20 trawl operations were conducted for seasonal maritime research in the same research area according to the operation mode of propeller. Based on navigation data, trawl fishing data, and engine performance data acquired during the towing fishing gear, and data of ship speed, hull resistance, fishing gear resistance, wind force and current force according to an incidence angle were estimated. The overall power for these loads was calculated and compared with the measured engine power, and the effects of wind force and current force on the engine power were investigated.

The United States enforces the seafood import regulations so-called the Marine Mammal Protection Act (MMPA), and by 2023, all exports of aquatic products and processed fish products by fisheries which have not obtained an “Comparability Finding” from the National Oceanic and Atmospheric Administration will be completely banned. Therefore, to respond to the US MMPA, it is critical to identify technologies and methods used in worldwide for reducing bycatch of marine mammals. In particular, marine mammals are frequently caught in five fisheries (trawl, gill net, trap, stow net and set net) in Korea, which is facing a great challenge. This study presented bycatch reduction methods by five fisheries, classified the methods by country, and suggested appropriate reduction methods which can be applied in Korea.

This study was investigated in order to find composition and density of fisheries resource using bottom trawl in April, July, August, and November 2022 in the East China Sea. The average density of fisheries resource was estimated using the swept area method. As a result, 35 species were collected from the East China Sea. These included 21 fishes, six crustaceans, six cephalopods and two echinoderms. Seasonally, the average density of crustacean individuals per unit area were highest in November (692.1 inds./km 2 ), while cephalopod individuals per unit area were highest in August (39.4 inds./km 2 ). The average density of fish individuals per unit area were highest in August at 355.0 (inds./km 2 ).

수산실무상 쟁점인 연근해 어업의 어업조정과 자원보전이라는 공익상 목적 으로 제정된「연근해어업의 어업조정 고시」는 법령보충규칙에 해당하고, 고시제정당시 전체 동해구 트롤어선 43척 중에 14척에 한해서만 선미식 조업을 허 가하고 나머지 어선에 대해서는 선미식으로 건․개조를 금지하게 함으로써 기존 에 선미식으로 조업했던 어선이 대체 · 상속 · 매매 · 침몰되었을 때 선미식 조업 어선을 양수한자는 선미식 조업을 할 수 있는지 논란이 된 것이다. 이것은 어 업허가의 양도성과 직결되는 것으로 어업허가는 대물적 허가인지 아니면 혼합 적 허가인지에 대해 의견이 나누어지지만 대물적 허가로 보는 것이 다수견해이 다. 대물적 허가로 보는 견해나 추가된「수산업법」제44조 규정취지를 해석하 면 어업허가는 양도되어야 하지만, 대법원 판결은 기존 어업허가를 받은 자에 게 어선을 양수하더라도 어업허가권까지 양수되는 것이 아니고 양수인은 어업 허가를 새로이 받아야만 허가어업에 종사할 수 있는 것이라고 하여서 어업허가 의 권리양도를 부정하고 있다. 따라서 판례에 따르면 양도인은 선박을 양도한 것이지 어업허가를 양도한 것은 아니므로 선미식 조업 허가권은 여전히 양도인 에게 존재하고, 양수인은 선박을 양수 받은 것이고, 선미식 조업 허가권을 양수 받은 것은 아니다. 동해구 트롤어선의 어업허가권의 법적성격과 승계는 수산실 무에서는 계속 분쟁이 지속되는 문제이므로 이에 대한 연구는 학문적이나 실무 적으로 검토할 가치가 있다.

In this study, a comparative test operation was conducted through the alternate haul method to examine the selectivity of the four mesh sizes (60 mm, 90 mm, 110 mm, and 130 mm) of the trawl codend. The selectivity was analyzed using the SELECT model considering the fishing efficiency (split parameter) of each fishing gear in the comparative test fishing operation in the trawl and the maximum likelihood method for parameter estimation. A selectivity master curve was estimated for several mesh sizes using the extended-SELECT model. As a result of analyzing the selectivity for silver croaker based on the results of three times hauls for each experimental gear, it was found that the size of the fish caught increased as the size of the mesh size increased. When the selectivity for each mesh size analyzed by the SELECT model considering the split ratio was evaluated based on the size of the AIC value, the estimated split model was superior to the equal split model. Based on the master curve, the 50% selection length value was 2.893, which was estimated to be 136 mm based on the mesh size of 60 mm. In some selectivity models, there was a large deviance between observed and theoretical values due to the non-uniformity of the distribution of fished length classes. As a result, it is considered that appropriate sea trials and selectivity evaluation methods with high reliability should be applied to present trawl fishery resource management methods.

In September and October 2020, combined acoustic and trawl surveys were conducted in the northwestern sea of Jeju Island. In the survey area, a region, so called Jeju region, was designated to esimate the biomass of chub mackerel and jack mackerel using a trawl survey method and frequency difference method. In the September survey, the weight ratios of jack mackerel and chub mackerel to the total catch were 24.6% and 2.8%, respectively, and in the October survey, those ratios were 24.9% and 20.7%, which were used to calculate their biomass (trawl survey). Using the frequency difference range (–8 to –3dB) corresponding to two species in 120 and 200 kHz, their biomass was estimated (frequency difference method). As a result, the biomass of two species from the trawl method was 3252.3 tons in September and 5777.0 tons in October. The estimated biomass by the frequency difference method was 4926.6 tons in September and 7521.5 tons in October. It was the first trial to estimate the biomass of two species using the trawl and frequency differencing methods in South Korea although there were some differences between two methods. In addition, horizontal distributions of acoustic backscattering strength over the entire survey area were mapped.

Trawl fishing is a fishing method in which a large, motorized trawler tows a bag-shaped net to catch fish living at the bottom or middle layers. For a trawl gear, it is of utmost importance to select the gear size and towing speed suitable for the effective horsepower (EHP) of the trawler in the design stage. In general, the power required to move an object is proportional to the product of the object speed and resistance; therefore, there are various choices for the gear resistance and towing speed given the effective horsepower of the trawler. However, there have been few studies on the gear design of an appropriate scale for the towing speed given the effective horsepower of the trawler. In this study, the resistance and shape of three types of midwater trawl gears were analyzed using SimuTrawl, a computer simulation tool. In addition, the relationship between the propulsion force and speed of the ship was clarified when the size and effective horsepower of the trawler were determined. Finally, we suggested the relationship between the towing speed and the resistance of the gear when the trawler towed the net was investigated, and a specific method of selecting the gear size according to the towing speed.

최근 인터넷 및 디지털 기술 발전으로 인하여 그 어느 때보다도 많은 사람들이 저작권으로 보호된 표현을 만들어내고 있으며, 이러한 저작권에 대한 침해도 다수 발생되고 있다. 저작권 트롤 (copyright troll)은 저작권 제도를 악용하려고 2010년대부터 출현한 것이나, 특허 트롤에 비해 주목을 받지 못하고 있는 상황이다. 그러나 저작권 트롤은 한 번에 수백 또는 수천 명 규모의 피고를 대상으로 권리 주장을 할 수 있다. 또한, 불법 행위의 특정 및 입증도 특허 소송에 비해 용이 하기 때문에, 필요한 비용과 화해로 인해 얻을 수 있는 총액을 고려할 경우 특허 소송보다 쉽게 고액을 얻을 수 있어 트롤에게 매력적인 비즈니스 모델이 될 수 있다. Prenda Law나Righthaven 등, 저작권트롤이 가장 활발하게 활동한 곳은 미국이며, 법정손해배상 제도 등을 배경으로 저작권 트롤이 활동하였다. 미국과 달리 일본은 저작권 트롤에게 매력적인 시장이 아니라고 판단되어 과거 및 현재까지 저작권 트롤의 활발한 활동은 보이지 않는다. 그러나, 일본에서도 최저 손해액으로서 라이선스료 상당액을 추정하는 규정이 존재하고 있다. 향후 기술 발달에 따라 권리 행사 비용이 더 내려가면 일본에서도 저작권 트롤의 비즈니스 모델이 탄생 할 여지가 있다고 보이며, 이러한 저작권 제도를 악용하는 트롤에 대하여 적절한 조치가 필요해질 것이다. 아울러, 한국에서 문제가 되고 있는 청소년들의 저작권 침해에 대한 형사처벌 협박처럼 저작권 침해로 인한 형사처벌이 지나치게 가혹한 사례가 일본에서 있는지에 대해서도 조사 및 고찰해보고자 한다.

At ship design stage, the maneuverability is generally estimated based on the empirical formula or the computational fluid dynamic (CFD), which is one of the numerical simulation methods. Using the hydrodynamic derivatives derived through these methods can quantitatively estimate the maneuverability of target vessels and evaluate indirect maneuverability. Nevertheless, research on estimating maneuverability is insufficient for ships not subject to IMO maneuverability standard, especially fishing vessels, and even at the design stage, the empirical formula developed for merchant ships is applied without modification. An estimation error may occur due to the empirical formula derived from the regression analysis results of a model test if the empirical formula developed for merchant ships with different hull shapes is applied to fishing vessels without any modification. In this study, the modified empirical formula that can more accurately estimate the fishing vessel's maneuverability was derived by including the hull shape parameter of target fishing trawlers in the regression analysis process that derives Kijima et al. (1990) formula. As a result, the modified empirical formula showed an average estimation error of 6%, and the result improved the average error of 49% of Kijima et al. (1990) formula developed for merchant ships.

Engaged in trawling in limited fishing grounds with a number of fish schools could cause collisions between fishing vessels. Therefore, providing accurate maneuver information according to the situation could be regarded as essential for improving seafarers safety and fishing efficiency as well as safety of navigation. It is difficult to obtain all maneuver information through sea trial tests only, so a method through empirical formula is necessary. Since most empirical formulas are developed for merchant ship types, especially the characteristics of hull shape parameter like CbB/L and dCb/B etc. are clearly different between fishing vessels and merchant ships, this could occur estimation errors. Therefore, in this study, the authors have selected target fishing vessels and merchant ships and analyzed the characteristics of hull shape parameter according to the ship types. Based on this analysis, the empirical formula developed for the merchant ship type has applied to the target fishing vessels; it has verified through the turning motion simulation that the estimation error could be generated. In conclusion, it is necessary to include the characteristics of the hull shape parameter of fishing vessels in the empirical formula in order to apply the empirical formula has developed for merchant ship types to fishing vessel types.

Thousands of pelagic and demersal fishes inhabit the waters around Korea and many of them are overexploited. One of the reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the otter trawl fishery from 1960s to 2010s. Gross tonnage was decreased stably, but horse power was increased annually. The perimeter of net mouth was somewhat longer, but little changed. Color fish finder was utilized from the mid-1960s. Hydraulic net drum were introduced in the early 1990s, and supply rate was gradually increased. Surveys on the supply and upgrading of fishing equipment utilized visiting research. Therefore, the relative fishing power index in the trawl fishery increased about two to three times in the 2010s compared to the 1980s. The results are expected to contribute to reasonable fisheries stock management.

The annual production of silver croaker (Argyrosomus argentatus) in Korean towed fishing gears has been increased in recent five years. In 2017, the annual production of silver croaker in metric ton was increased 99.2% compared to 2013. However, the research for silver croaker has been focused on ecology in Korea. There has not been enough research in terms of fishing gears. Therefore, the research for retention probability for towed gears was conducted on covered codend method from June, 2016 to July, 2018. During the experiments, the total catch of silver croaker was 1,563. The geometry of the experimental trawl gear was controlled by trawl monitoring system; net height was 3.3 m, distance of trawldoors was 59.8 m and distance of wing net was 17.3 m. The selection curve for silver croaker was estimated by a logit model. The analysis was applied with the confidence interval to reduce uncertainty of the estimation. The l50 was 13.87 cm and its selection range was 2.71 cm. P-value was estimated at 0.99. The mesh size for silver croaker in towed gears needs to be adjusted by considering its minimum maturity length, stakeholder’s interests and fisheries regulations.