The chromate adsorption capacities of Pachymeni- opsissp.werecomparedwithrespecttosamplingtimes from February to July. Although the size and mor- phology of the alga varied according to sampling time, no seasonal variation in the chromate adsorption ca- pacity of the alga was found. Since Pachymeniopsis sp. grows extensively from April to May, this period is taken to be the best time for mass collection of the alga.