Epizoic green algae on fairy shrimp, Branchinellites kugenumaensis (Ishikawa, 1895) (Thamnocephalidae, Crustacea) collected from a paddy field in Azumino City, Nagano Prefecture, central Japan

Abstract

Epizoic algal flora and water environment in a paddy field, where great number of green-colored fairy shrimps (Branchinellites kugenumaensis (Ishikawa, 1895); Thamnocephalidae, Anostraca) inhabited, were examined in Azumino City, Nagano Prefecture, central Japan. The dominant algal species found on leaf-like shaped limbs of the green-colored fairy shrimps was identified as Characium gracilipes Lambert (Chlorophyceae). No C. gracilipes was found in planktonic, epiphytic, and epipelic algal communities, nor on the cladoceran in the studied paddy field. Oxy-gen production and consumption of green-colored fairy shrimp, estimated by light and dark bottle method, was about 6 and 3 mg O2 wet 1000 mg wt-1 hr-1., respectively. Mutual relationship between fairy shrimp and the epizoic algae was not supported in terms of oxygen and nutrient exchange.