Sporophytes of the warm temperate perennial kelp Ecklonia cava typically mature after two years, but some populations mature in the first year. To understand the dynamics of these early-maturing forms of E. cava, one isolated population (5 ha) was monitored at Moroiso, Miura City in Sagami Bay, Japan from 2015 to 2020. From 2015 to 2018, the sporophytes were able to repeatedly recruit due to high maturation rates (92% at maximum) in the summer. However, these sporophytes disappeared due to browsing by the rabbitfish Siganus fuscescens and/or typhoon-related high waves in autumn or winter. The early maturing nature of the strain appears to help maintain the kelp forest despite these harsh conditions and could be a candidate for seed production and transplantation to deforested areas.
However, in 2019 and 2020, the kelp forest was completely destroyed by unusual high water temperatures (the highest in 40 years) and increased browsing by S. fuscescens and the parrotfish Calotomus japonicus, as well as larger typhoon waves. To avoid extinction, this strain should be kept in laboratory stock culture for further use.
本研究の目的は,電子化された水産物卸売市場で,市場関係者が電子化されたデータを閲覧する場合に,閲覧目的に適したデータの提供方法を検討することであった。対象は西日本魚市場で運用されている産地電子情報ネットワークの利用者782名とした。分析の結果,利用者の56.5%がPCのみでデータを閲覧していることが分かった。携帯端末での閲覧頻度が高い利用者は,選別作業員および荷役だった。携帯端末利用者に対するデータ提供の改善案として,データが更新された際に,携帯端末に通知を送ることが効果的であると考えられる。
Permeability may be an important habitat for submerged sand organisms. Therefore, a simplified permeability test method was tried and compared with the Creager's permeability coefficient to verify the validity of the measured value as a permeability index. As a result, we found that the two methods were in good agreement, with a sharp decrease in permeability at an effective diameter of 0.2 mm. This method may be used to obtain a low-cost and easy-to-use measure of permeability indicators on site.
The 2023 JSFE Spring Symposium on “Sustainable Fisheries in Southern Kyushu Under Cooperation Among Industry, Government and Academia” was held on 28 May 2023 at Faculty of Fisheries, Kagoshima University. Four case studies were introduced by the fisherman, local government staff, and the staff of private companies. This report summarized the symposium.