日本水産工学会誌
Online ISSN : 2189-7131
Print ISSN : 0916-7617
ISSN-L : 0916-7617
56 巻 , 3 号
選択された号の論文の8件中1~8を表示しています
  • 江幡 恵吾, 山下 裕輔, 井ノ原 康太, 不破 茂, 木村 郁夫, 保 聖子, 新町 利明
    2020 年 56 巻 3 号 p. 149-158
    発行日: 2020年
    公開日: 2020/09/01
    ジャーナル オープンアクセス
    棒受網漁業で漁獲されたカタクチイワシとウルメイワシを氷蔵保管し,筋肉中に含まれるATP 関連化合 物の濃度および死後硬直の変化を調べた。筋肉中に含まれるATP,ADP,AMP の合計量はカタクチイワ シよりウルメイワシの方が速く減少した。漁獲6 時間後までのK 値は,カタクチイワシで0 〜4.6%,ウル メイワシで0.1 〜4.2% で推移した。死後硬直の開始はウルメイワシよりもカタクチイワシの方が遅かった。 漁獲時に網内で激しい運動をしたカタクチイワシを生簀内で短期蓄養するモデル実験では,筋肉中のATP 濃度は72.2 時間後まで低い値を示し,96.2 時間後から回復する傾向があった。
  • 宮本 佳則, 内田 圭一, 浅井 咲樹, 吉田 達, 森 恭子, 笹倉 豊喜
    2020 年 56 巻 3 号 p. 159-164
    発行日: 2020年
    公開日: 2020/09/01
    ジャーナル オープンアクセス
    As for the scallop farming in Mutsu Bay, the scallops are cultivated in longline method cultured facilities. It is necessary to install a buoy to keep cultured facilities at the most suitable depth with the growth of the scallop. It is necessary for the fisherman to check a subsidence state of facilities every day. In addition, it is necessary much labor and expenses because the fisherman owns plural cultured facilities in the large sea area. Therefore, we built the system that remoteness watched depth and the water temperature of scallop cultured facilities with an ultrasonic telemetry system and a mobile phone network that we largely improved efficiency of the fishery work and improved productivity. The fisherman can confirm the situation of facilities at an information terminal by almost displaying a monitoring result in Web in real time. Furthermore, as for the system installed in the cultured facilities, 9-month continuation operation was confirmed in a proof examination to minimize the burden on fisherman.
  • 梶原 直人, 佐々 真志
    2020 年 56 巻 3 号 p. 165-172
    発行日: 2020年
    公開日: 2020/09/01
    ジャーナル オープンアクセス
    The influence of the shape of gravel on sediment hardness was discussed from the relationship between circularity degree and friction coefficient which can be easily measured. Calculation of circularity was based on the measurement with 30 grains per sample and considered to be sufficiently accurate. The decrease in circularity due to the change in the gravel shape corresponded well to the increase in the friction coefficient calculated from the angle of repose. In addition, the measured values of vane shear resistance, which is an index of sediment hardness, showed marked fluctuations that are consistent with the increase in friction coefficient due to the decrease in circularity. These results indicate that the circularity of gravel and associated variation in the friction coefficient can be utilized to infer the vane shear resistance, which is known to serve as a burrowing capability indicator for diverse benthic organisms.
  • 梶原 直人, 佐々 真志
    2020 年 56 巻 3 号 p. 173-179
    発行日: 2020年
    公開日: 2020/09/01
    ジャーナル オープンアクセス
    Vane shear strength has played an extremely important role as an indicator of the burrowing capabilities for diverse benthic organisms. For the purpose of simple measurement of the vane shear strength and elimination of error by the measurer, we attempted automatic measurement of vane shear strength by connecting a vane tester to a commercially available PET bottle opener. As a result of comparing the measured values of the vane shear strength with manual measurement with gradients in the particle size, density, and circularity of the substrate, the coefficient of determination in the regression line of manual measurement was high in all cases, but there was no statistically significant difference between them. The results of manual and automatic quantitative measurements also corresponded well to the increase in the friction coefficient tanΦcalculated from the angle of repose of the substrate. These results indicate the possibility of automating the measurement of vane shear strength by using a motor with an appropriate range of starting torque.
  • 荒巻 能史
    2020 年 56 巻 3 号 p. 181-184
    発行日: 2020年
    公開日: 2020/09/01
    ジャーナル オープンアクセス
    The Japan Sea is called a “miniature ocean”because it has its own thermohaline circulation, which is similar to that of the open ocean. Therefore, it may be possible to detect oceanic responses to climate change such as global warming in a relatively short time by monitoring physical and biogeochemical conditions in the Japan Sea. In this paper, I introduce our finding of the past on global warming impacts in the Japan Sea. Historical data and recent observations show a centennial-scale oxygen decrease in the bottom water at the depth below 2000m from about 250µmol/kg in the late 1920s to about 200µmol/kg at present. This oxygen decline implies weakening of thermohaline circulation, which corresponds to a centennial-scale warming in the northern area of the sea where the bottom ventilation could occur. Using the spatial distributions of chlorofluorocarbons, we found that the scale of thermohaline circulation of the sea after 1975 have decreased by 21-30% in the deep water and 15-41% in the bottom water compared with those before 1975. Using the vertical profiles of total carbonic acid and total alkalinity, we found that anthropogenic CO2 concentration in the sea increase sharply over the past 20 years and ocean acidification of the sea is more active than other marginal seas.
  • 三浦 浩, 伊藤 靖, 河野 大輔, 中西 豪
    2020 年 56 巻 3 号 p. 185-190
    発行日: 2020年
    公開日: 2020/09/01
    ジャーナル オープンアクセス
    It is feared that seawater temperature rises and other changes in the marine environment due to climate change will greatly affect the marine ecosystems and fisheries in the sea waters around Japan. Moreover, possible effects of climate change are being combatted both at home and abroad not only by “alleviation”, designed to control and otherwise manage greenhouse gas emissions, but also by promoting “adaptation” to already visible effects and effects expected to be unavoidable on a mid-to-long-term basis. Against such a backdrop, in 2017 the Fisheries Agency established “Guidelines for Measures to Develop Fishing Grounds in Response to Climate Change”. This report, based on the above guidelines, summarizes procedures and other details for preserving and adapting seaweed beds, tidal flats, coral reefs, coasts, and offshore waters.
  • 藤井 賢彦
    2020 年 56 巻 3 号 p. 191-195
    発行日: 2020年
    公開日: 2020/09/01
    ジャーナル オープンアクセス
    Ocean warming and acidification are both caused mainly by excess emission of anthropogenic CO2. Recent studies have revealed that the two phenomena are anticipated to damage marine ecosystem and societies in future in complex ways. To address the issue, mitigating these phenomena by cutting manmade CO2 is a royal road, but at the same time we also need to take other actions which include implementation of adaptive strategies to local societies and industries, such as relocation of marine parks and aquafarms, switching target species of fisheries and aquaculture, and changing aquaculture methods and practices accordingly. To provide guidelines necessary for applying future adaptative strategies locally based upon scientific insights, future projection of marine ecosystem and societies in response to ocean warming and acidification needs to be carried out precisely and with high accuracy and rapidity.
  • 海藻草場を利用した増養殖の展開
    堀 正和
    2020 年 56 巻 3 号 p. 197-200
    発行日: 2020年
    公開日: 2020/09/01
    ジャーナル オープンアクセス
    In the framework of the Sustainable Development Goals (SDGs)led by the United Nations, it is required to develop coastal management methods to achieve both sustainable food production and environmental conservation as a climate change countermeasure. Aquaculture is an important food production method now being developed in coastal areas around the world, although recent climate change has caused several negative effects on aquaculture through ocean acidification, high seawater temperature and anoxia/hypoxia in relation to high water temperature. Blue carbon ecosystems are the most important ecosystems functioning as a countermeasure for global climate change. Not only does it mitigate green-house gas emission by sequestration and storage of blue carbon derived from atmospheric CO2, but it also functions as an adaptation measure utilizing the buffer function against ocean acidification and moreover as water quality improvement. Based on integrating sustainable use of coastal areas with coastal environmental conservation, several aquacultures using the blue carbon ecosystems are now practiced such as oyster aquaculture using seagrass beds and macroalgal aquaculture maximizing CO2 sequestration.
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