A study to track the way some fish species behave around fish aggregation devices or FADS in the Western Pacific is underway.
FADs are used by large fishing fleets to attract schools of tuna into a concentrated habitat.
But environmentalists say the practice is dangerous because the devices not only attract tuna but other fish species or by-catch which is later dumped.
The principal scientist David Itano of the University of Hawaii says their research involves fish being implanted with transmitters to track their presence or absence around a particular FAD.
"The idea is that we are again looking for ways to concentrate only on catching the valuable tuna and avoiding the small undersized tuna and the bycatch species."
David Itano of the University of Hawaii
The study is being carried out by the International Seafood Sustainability Foundation on board the purse seiner Cape Finnister which was in American Samoa recently.