In January 2002, IATTC scientists began an experiment to determine whether feeding and spawning events of yellowfin tuna can be detected from data recorded by archival tags.  Archival tags are surgically implanted into the body cavities of fish; they contain a microprocessor that collects data on ambient water temperature, pressure and light and on internal body temperatures of the fish.  The tags were implanted in 12 yellowfin, which are being held in one of the reserve broodstock tanks.