Title Seedling production in Eisenia arborea using Suruga Bay deep-sea water for restoration of kelp beds in isoyake area
Authers Kazumi NIMURA, Hiroyuki NODA and Kazutoshi OKAMOTO
Keywords Deep-sea water, Eisenia arborea, Isoyake, Seedling, transplantation
Citation Bull. Fish. Res. Agen. No.32, 115-118, 2010
Eisenia arborea is distributed from central to southern Pacific coast of Japan. The wild sporophytes of the kelp extincted along the coasts of Omaezaki and Makinohara Cities in Shizuoka Prefecture after deforestation called isoyake (cf. non-urchin barren here) in 1980’s. Fortunately, we have cultured the native sporophytes collected from Omaezaki Cape in our laboratory. Suruga Bay deep-sea water (DSW) is nutrient rich, cold and clean sea water pumped from two depths of 397 and 687m with pipelines. As nitrate and phosphate concentrations of DSW (ex. NO3=21.1~30.7μM, PO4=1.7~2.8μM in 2007) are higher than that of surface sea water (ex. NO3=4.0~14.4μM, PO4=0.3~1.2μM in 2007), growth rate of juvenile Eisenia sporophyte was higher in DSW than surface seawater. Therefore, we used DSW as culture medium for seedling production. Seedling production was started by the homogenization of the cultured gametophytes with the mixer. Culturing 1~2 weeks later, numerous number of the microscopic free living sporophytes were obtained. These sporophytes was settled on the strings within a day in batch culture and then cultured for about one month in DSW. This seedling of the E. arborea was transplanted to isoyake area for restoration of the kelp forests. The method of culture and transplantation on blocks were described here.
URI http://www.fra.affrc.go.jp/bulletin/bull/bull32/115-118.pdf