Abstract
The effect of water flow conditions on the feeding behavior of herbivorous fish in Phyllospadix japonica meadow was studied in October 2005 in Old Islands, Shimane Prefecture, Japan. P. japonica distributed between-0.5 m and-3.7 m relative to datum level. Leaves with distinctive bite marks by the herbivorous fish were found throughout expansive areas vegetated by P. japonica. At the areas in which bite marks on the leaves were confirmed, the plant size of P. japonica was small. P. japonica exposed to greater water flow condition experienced less grazing compared to low flow areas that were grazed. This result indicated that herbivorous fish seemed to avoid the areas exposed by increased water flow.
