Distribution of macrobenthos and bottom environment parameters in Toyama Bay [Japan]
2006
Tsujimoto, R.(Toyama-ken. Fisheries Research Inst., Namerikawa (Japan)) | Shozen, K. | Hayashi, S. | Watanabe, T. | Imao, K.
Distribution of macrobenthos and bottom environment parameters were investigated in Toyama Bay, Sea of Japan, in May 2001. A total of 253 species and 2,238 individuals were collected from 60 stations, using a Smith-McIntyre grab sampler (1/10 square m). Numerical density, biomass, number of species and diversity (H') ranged from 0 to 124 individuals/0.1 square m, 0 to 7.60 g wet/0.1 square m, 0 to 49 species/0.1 square m and 1.06 to 5.06 bit, respectively. Bottom environment and biotic parameters of five areas, i.e., western, innermost, eastern, Kokutou and central were compared with each other. Silt-clay content, ignition loss, acid volatile sulfide and COD were relatively high in the innermost and central areas, especially in front of the Oyabe River and the Jinzu River. In contrast, these parameters showed low values in the eastern and Kokutou areas. Macrobenthos density was high in the eastern and Kokutou areas, whereas it was low in the western area. Polychaetes accounted for 59% of the total abundance. Comparison with a previous survey conducted by Kitamori (1971) showed that the densities of several polychaete species decreased drastically during the interval of thirty years.
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