Add to ORKGIn order to evaluate seasonal changes in respiration rates of the Peruvian scallop Argopecten purpuratus, oxygen consumption was measured in situ for three ranges of sizes (R1: 30 - 40mm, R2: 45 - 55mm and R3: 80 - 90 mm) in Atenas beach (Paracas Bay) during February, March and August 2007. Four to six acrylic chambers connected to submersible pumps were installed to set an opened/closed recirculating system. Once the scallops were acclimated, initial water samples were taken with the opened recirculation system, after that, the closed recirculating system was set and one hour later final samples were taken. Respiration rates (mg 02 h-1) appeared to be directly related with size of individuals as its shown in the August results, with value...