- 甲殻類の研究 (ISSN:02873478)
- no.11, pp.124-137, 1981-12
The ecological distribution of phytal amphipods on seaweeds were investigated in a Sargassum bed at the coast of Tomioka Peninsula, Amakusa, Kyushu. Eight plants of 4 Sargassum species were collected underwater by the vertically stratified sampling method in May when these seaweeds fuliy grown up. By this sampling, 10 species of caprellids and 21 species of gammarids were obtained. The similarities among epiphytic amphipod assemblages of each host plant were analyzed for Caprellidae and Gammaridea respectively. These assemblages resembled each other, consequently it was speculated that these epiphytic amphipods generally have no specific preference to the host plants. Simultaneously, two groups were recognized in both taxa, namely, one group consists of S, patens and S. horneri which were collected in the outer part of the Sargassum bed, another is S. thunbergii and S. hemiphyllum which mainly flourish inside. The difference seemed to be caused by the factors which related with wave action or other hydrodynamic conditions. In the vertical distribution of the biomass of each alga, the weight of higher part was normally heavier than that of lower part, and this tendency was also observed in the individual number of amphipods on each part. Vertical distribution of 6 species of amphipods (Caprella decipiens, C. danilevskii, C. tsugarensis, Ampithoe orientalis, Aoroides columbiae, Pontogeneia rostrata) showed high positive correlations with those of seaweeds biomass. Exclusive of S. horneri, C. monoceros and Phliantidae sp. 1 also showed positive correlations with the vertical distribution of seaweed biomass like other species. On S. horneri, however, they mainly occurred on the lower part of seaweed and showed negative correlation.