Sperm of the scallop Pecten maximus (L.) can be collected by various methods for artificial reproduction. Characteristics such as spermiation time, fertilizing capacity, respiration and motility of the spe can be modified by collection method. In the current study, sperm was collected quickly by scarification, but its quality was only average. When thermal shock or serotonin injection was used to stimulate the release of sperm, it was collected and concentrated as "dry" as possible after exit fr the kidney. Its quality was comparable to that of diluted sperm collected after thermal shock, a technique commonly used in bivalve hatcheries. The results also showed that serotonin injection systematically decreased spermiation time and induced the production of high quality sperm and henc is the preferable method to collect sperm for artificial reproduction.