Seasonal growth and population structure of hijiki (Sargassum fusiforme) was surveyed at two rocky reefs contiguous to each other, i.e.Saba-Shima and Sen-emon-Dashi, in Hime, Kushimoto-cho, Wakayama Prefecture. In spring, the harvest season of hijiki for fisheries, thalli in Saba-Shima were significantly larger than thalli in Sen-emon-Dashi. A permanent quadrat was set at each reef and the growth pattern of hijiki in the quadrat was monitored monthly from June 2012 to April 2013. In the population at Saba-Shima, main branches had already been developed in many hijiki thalli in June, and their rapid elongation began in November. On the contrary, the population at Sen-emon-Dashi was dominated by rosette-type thalli with cauline leaves extended radiately and no main branches developed during summer and autumn. Frequency of thalli with developed main branches increased and their rapid elongation began in January at Sen-emon-Dashi. Even after the onset of rapid branch elongation, daily elongation rate was far larger in the population at Saba-Shima than in the population at Sen-emon-Dashi. Difference in seasonal growth and developmental pattern was attributable to the difference in spring thallus size of hijiki between the two reefs.

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Annual net production of Ecklonia kurome Okamura growing off Gounoura, Iki Island, northern Kyushu, was investigated from December 2011 to December 2013. Densities of adult E. kurome ranged from 17.6 to 40.8 inds. m^-2 and their biomass was 302 to 1,532 g dw m^-2. The number of newly produced bladelets ranged from 0.01 to 0.23 day^-1, being lower in summer and higher in winter. Annual net production of E. kurome was estimated at 2,785 to 2,880 g dw m^-2 year^-1. Compared with the congeneric species Ecklonia cava Kjellman, E. kurome in northern Kyushu had a lower weight of maximal biomass whereas they shared an equivalent level of annual net production.

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In 2013, summer water temperature off Iki Island was the highest among the eight years from 2006 to 2013. Deterioration of kelp (Ecklonia spp. and Eisenia bicyclis) beds occurred around Iki Island. Summer water temperature was higher on the western coast than the southern coast of the island, and within the same area it was higher in shallower zone than in deeper zone. In late August and early September, fronds of kelp were lost, and the lower part of the stipe had lost its color and was bent. Deterioration of kelp progressed more rapidly in the areas with relatively higher water temperature. Until October, kelp beds in deeper zones or along the southern coast of the island, where water temperature was relatively low, remained with less damages. But in October to December, the kelp beds in these areas were heavily grazed by herbivorous fish. Juveniles of the kelps appeared in late December and their density was proportional to the amount of fronds that remained at the previous reproductive season (October to November). In this process of the kelp bed deterioration in Iki Island, higher water temperature and grazing by herbivorous fish affected the kelp beds with a time lag and spatial difference, rather than occurring simultaneously.

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To identify the cultivable epiphytic bacteria obtained from the unialgal culture strain of the red alga Gracilariopsis chorda (Holmes) Ohmi collected from the estuary of Katsuura River in Tokushima Prefecture in southwest Japan, morphological and phenotypic classification and genetic analysis were carried out. Eight kinds of cultivable bacteria were isolated. Isolate UGC1-1 (bacterial population: 7.5×10⁷ cfu g^-1), UGC1-2 (4.0× 10⁷ cfu g^-1) and UGC1-3 (5.0× 10⁶ cfu g^-1) were isolated from Marine Agar plates. Isolate UGC1-4 (5.0×10⁶ cfu g^-1) and UGC1-5 (1.0×10⁶ cfu g^-1) were isolated from 1/10 ORI and CAM plates, respectively. Isolate UGC1-6 (1.0×10⁵ cfu g^-1), UGC1-7 (6.0×10⁴ cfu g^-1) and UGC1-8 (2.0×10⁴ cfu g^-1) were isolated from CVT plates. The genetic analysis based on partial 16 SrRNA gene sequences (ca. 450 bp) revealed that the Isolate UGC1-1, UGC1-2, UGC1-3, UGC1-4, UGC1-5, UGC1-6, UGC1-7 and UGC1-8 related closely to Ascidianbacter aurantiacus (Similarity 93.2%), Ruegeria halocynthiae (99.5%), Roseovarius sediminilitoris (97.2%), Litoreibacter janthinus (99.3%), Zobellia russellii (99.8%), Marinobacter salarius (99.1%), Granulosicoccus antarcticvs or G. coccoides (97.9%) and Labrenzia aggregata (99.8%), respectively. The Isolate UGC1-1 was suggested to be an undescribed taxon assigned to the family Flavobacteriaceae based on genetic analysis.

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In summer of 2013, occurrence of kelp (saccharinian species) was surveyed by scuba diving at five sites on the coast of southern Sakhalin (Yablochnyy, Bogdanovitch, Krilion, Korsakov and Lesnoye), Russia, and one site on the coast of northern Hokkaido (Wakkanai), Japan. Satellite-images of surface water temperature along the coast of these sites were analyzed to perceive the relationship between water temperature and occurrence of kelp. Satellite images indicated that water temperature at the sites of the Sea of Japan (Yablochnyy, Bogdanovitch and Wakkanai) was higher and highest at Wakkanai. The site of Okhotsk Sea (Lesnoye) was the coldest, and the site of Aniwa Bay (Korsakov) showed temperatures intermediate between the Sea of Japan and Okhotsk sites. In general, the kelp Saccharina japonica var. ochotensis was dominant among saccharinian algae and its occurrence depended on water temperature of the surveyed sites. At Wakkanai, S. japonica var. ochotensis was scarce whereas the highest standing crop and density was observed at Korsakov, the second coldest site among the all sites. Only at Wakkanai, the sea urchin Mesocentrotus nudus appeared and the population of S. japonica var. ochotensis was composed only of first-year sporophytes. Species diversity of kelp was highest but S. japonica var. ochotensis has never been found at Lesnoye. Occurrence, standing crop, density and species diversity of saccharinian algae were considered to be affected by the water temperature.

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