著者

津村 良祐 木村 暢夫 藤森 康澄 岩森 利弘

出版者

北海道大学大学院水産科学研究院 = RESEARCH FACULTY OF FISHERIES SCIENCES, HOKKAIDO UNIVERSITY

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.57, no.1-2, pp.19-24, 2006-11

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Ship motions on the small fishing boats for scallop cultivation in Funka-Bay, Hokkaido, are usually influenced by the dynamic force of large scale cultivation facilities. On the rough sea condition, it would generate fatal ship motions like large amplitude rolling motion. To reduce such ship motions under fishing conditions, we designed a new type of mooring device with buffer materials used as absorber for ship motions. We carried out the tank experiment used the model in the wave conditions corresponded to the actual fishing operation to confirm the effect of reducing ship motion. For the waves in the long-period frequently generated under rough sea, the damping effect of the absorber was effective to reduce rolling motion, and accounting for nothing less than 10.0% compared with the normal mooring device without the absorber. As a result, the mooring device with absorber is effective for the improvement of seakeeping qualities of the fishing boats for scallop cultivation.

著者

清水 茂雅 堀口 明日香 山崎 浩司 川合 祐史

出版者

北海道大学大学院水産科学研究院 = Research Faculty of Fisheries Sciences, Hokkaido University

雑誌

北海道大学水産科学研究彙報 (ISSN:13461842)

巻号頁・発行日

vol.59, no.2, pp.37-42, 2009-08-03

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Recovery of heat-injured vegetative cells and spores of Clostridium perfringens was evaluated on selective media, CW Egg-yolk agar with kanamycin (ECW+A), Tryptose sulfite cycloserine agar(TSC+A)and modified Handford agar (mHFA). As a result of heat treatment at 54℃ for 15 min, viable counts of C. perfringens vegetative cells on a selective medium (ECW+A)was significantly less than those on non-selective media. This means C. perfringens vegetative cells should be in an injured state. Comparing of the three selective media, TSC+A was the best growth and recovery of heat-injured C. perfringens vegetative cells. Recovery on ECW+A was 1 log CFU/ml less than that on TSC+A. Supplementation of TSC+A with sodium pyruvate (0.1-0.5%) further enhanced recovery and detection of heat-injured C. perfringens vegetative cells, and its efficacy was the highest on TSC+A supplemented with 0.3% sodium pyruvate. Supplementation of TSC+A with sodium pyruvate did not affect recovery of heat-injured (95℃, 2 or 60 min) C. perfringens spores. These findings suggest that TSC+A is the most favorable medium for enumeration of C. perfringens and supplementation with sodium pyruvate improves recovery and detection of heat-injured C. perfringens.