National Institute for Environmental Studies 1 article published in JoVE Biology Measuring Photophysiology of Attached Stage of Colacium sp. by a Cuvette-Type Fast Repetition Rate Fluorometer Takehiro Kazama1,2,3, Kazuhide Hayakawa4, Koichi Shimotori1,2, Akio Imai1 1Lake Biwa Branch Office, National Institute for Environmental Studies, 2Center for Regional Environmental Research, National Institute for Environmental Studies, 3Graduate School of Human Development and Environment, Kobe University, 4Lake Biwa Environmental Research Institute Fast repetition rate fluorometer (FRRf) is a beneficial method for measuring photosystem II photophysiology and primary productivity. Here we describe a protocol to measure PSII photophysiology of epizoic alga, Colacium sp. on substrate zooplankton using cuvette-type FRRf.