In the Western and Central Pacific Ocean (WCPO), which accounts for over half of worldtuna production, purse seine effort and catch on floating objects have increasedsignificantly due to a rapid increase in the use of fixed and free-floating fishaggregation devices (FADs). FAD fishing has had an impact on the current status of thestocks of the three main target tunas in the equatorial WCPO, skipjack (Katsuwonuspelamis), yellowfin (Thunnus albacares) and bigeye (T.obesus). FADs have been shown to influence the behaviour and movement patternsof the three tuna species with the juveniles of each species occupying shallower habitatswhen associated with FADs. Aggregation of tunas around drifting objects increases theirvulnerability to purse seine gear, particularly for juvenile and small size classes.Further to the impacts on the target stocks, the use of FADs has increased thevulnerability of other fishes to the purse seine method, including some shark and billfishspecies. Given the concern over FAD-related fishing effort on target and bycatch species,there is a need to understand how FAD use affects target and bycatch stocks. Science needsto better support management decisions are highlighted including the need to identify themagnitude of broader community-level affects.