網袋式天然採苗によるアサリ漁業が行われている鹿児島湾北側の重富干潟では，出荷最盛期の夏季に網袋の破網と食害が発生している。網袋の近傍に設置したインターバルカメラで撮影された画像から7種の魚類が観察された。それらの行動を画像に出現，網袋に接近，ついばむ，引っ張るに分類した。クロダイ，キチヌが網袋をついばんだり，引っ張ったりする行動が見られ，アサリの貝殻が網袋の外側で観察された。回収時にそれらの網袋で破れが確認されたことから，クロダイ，キチヌが網袋を破り，アサリを捕食していると推定した。

他の船舶に比べ，漁船に代表される小型船は比較的小さな波高でも大きな動揺が生じる。特に小型漁船の場合，停船時における甲板上での作業中に大角度動揺が生じたならば，たとえ転覆に至らなくとも，海中転落等の危険性が生じうる。このため，波浪中の船体横揺れの時系列データがどの程度予測可能であるかを把握することは耐航性の研究上重要である。UenoらはFarmer and Sidorowitchの予測法が確率論的データである共振系狭帯域応答の波浪中の船体横揺れの時系列データに対しても有効であり，従来法である線形自己回帰モデルを用いた予測よりも優れていることを示した。共振系狭帯域応答の時系列データのような確率論的なものは，時間の経過とともに近傍ベクトルの数が変化し計算が不安定になる場合があった。それゆえに，Ueno and Fanは近傍ベクトルの数を一定に保つ方法を用いた。本研究では近傍ベクトルの数と予測精度に関する考察を行い，最適な近傍ベクトルの数が存在することが確認できた。

Snow crab Chionoecetes opilio catches in the western part of Sea of Japan reached their peak in the 1970s. Since then, the catch has been continuously declining to the present, and fishermen have eagerly desired the recovery of its stocks. Therefore, the national government has developed 25 protected areas by 2020 to contribute to the recovery of its stocks.

We attempted to verify the effectiveness of the protected areas by conducting surveys of population density of snow crab using crab cage trap. Survey sea areas were Tajima Protected Area 2 (T-2A), Akasaki Protected Area 2 (A-2A), and Hamada Protected Area 1 (H-1A). Tajima Protected Area 2 was found to be effective in protecting over 12th instar males and mature females. Akasaki Protected Area 2 and Hamada Protected Area 1 were also effective in protecting mature females. These protective effects are thought to be due to the water depth of the protected areas. In addition, most of the snow crabs captured were individuals with a carapace width of 60 mm or more. This result suggested that catching characteristics of crab cage trap were strongly influence.

This study concerning high-density polyethylene fishing net disposal elucidated the parameters of reclaimed oil from discarded fishing nets, with marine diesel oil and marine gas oil as a reference for comparison, and then assessed its suitability for the operation of the high-speed diesel engines in fishing vessels. From the result of the property analyses, the reclaimed oil was a flammable liquid including the ingredient of gasoline, kerosene, and marine gas oil, the flash point was 1 degree Celsius, thus it is necessary to mix it with mixing marine gas oil or marine diesel oil to use as fishing vessel fuel oil, the filter-plugging temperature was 1 degree Celsius, thus indicating the need to consider the possibility of filter blockage in cold regions. On the other hand, from the result of the engine test, the reclaimed oil showed no problem as the fuel oil in high-speed diesel engine. The reclaimed oil and the marine gas oil showed no differences in fuel consumption adjusted for calorific value and exhaust gas temperature, and NOx, SOx, CO, and CO₂ content in exhaust-gas with the reclaimed oil decreased in comparison with them in marine gas oil and marine diesel oil.

This paper describes the 30-year history of activities of the Japanese Society of Fisheries Engineering. Specifically, it outlines the chronological order of the Society’s activities in three phases: from the time of its establishment to 2000, from 2000 to 2010, and after 2010. At the end of this paper, the following appendix table is provided: 1) major events of the society (in chronological order), 2) names of past presidents and vice presidents, 3) list of society awards (awards of Japanese Society of Fisheries Engineering Society, best paper awards, encouragement awards, excellent technology awards, special awards, and student excellence awards), and 4) number of memberships.

Thirty years have passed since the Japanese Society of Fisheries Engineering was established in 1991. From the viewpoint of the Planning Committee, we summarized the contents of three representative society activities that have been conducted so far: 1) holding of annual meeting, 2) holding of symposiums, and 3) activities of research group, and presented future prospects.

The Japanese Society of Fisheries Engineering (hereafter referred to as the Society) is described in the Sea Grant Project of MIT and the Fisheries Engineering Laboratory of Hokkaido University regarding the fisheries engineering that represents the Society, but it does not necessarily show the current state. When the Society was established, it developed in a way that was different from the aspirations of Prof. Makoto Nakamura, who was the chairman at the time of the establishment of the Society. Currently, fisheries engineering including advanced marine environmental engineering, design of fishing villages and harbors, fishing boats, fishing production system, and measuring instruments is progressing in the main fields. Recently, however, the number of members has decreased, and the number of research presentations has also decreased. Now is the time to review people, goods, and money, and for example, to host international conferences and move in the direction of internationalization.

This is a summary report of the Japanese Society of Fisheries Engineers Spring Symposium 2022, 30th Anniversary Commemorative Roundtable Discussion, “The Road Ahead for Fisheries Engineering.” Before the roundtable discussion, the following were reported: 1) the current activities of the Society from its inception to the present; 2) trends in the number of papers by research field at scientific meetings; 3) trends in the number of symposia by research field; and 4) the origin of the Society, its characteristics, and proposed activities for the revitalization of the Society. In the roundtable discussion, the participants first introduced the trends of research and development in their respective fields of expertise. Then, there was a lively discussion on the direction of research and development that the fisheries engineering field should take toward the realization of the Sustainable Development Goals (SDGs) and carbon neutrality, as well as on technological issues that should be developed in the future. Finally, opinions were exchanged on the direction of the society’s activities.