The concept: Fish Aggregating Devices (FADs) as instrumented observatories of pelagic ecosystems.

Some pelagic fish species naturally aggregate around objects floating on the surface of the oceans. These floating objects are called FADs (Fish Aggregating Devices).

There is an urgent need to study the effects of FADs on the biology and the behaviour of tuna and find mitigation methods to reduce by-catch.		Instrumented FADs can form observatories of pelagic ecosystems.
More than 50% of the world catch of tropical tuna come from the industrial tuna fisheries around drifting FADs. These fisheries mainly catch juvenile tuna and other species not targeted, which raise ecological and ethical questions. Unfortunately, the real effects of FADs on the biology and the behaviour of fish are still unknown.		FADs can also help scientists to better understand the tropical pelagic ecosystems. Actually, these ecosystems are difficult to access and direct information are rare. By concentrating some pelagic fish species, FADs make them available to observations. By instrumenting them, FADs represent ideal scientific observation plateforms.

A first project, FADIO I, was funded by the European Union to develop new instruments and methods to observe fish around FADs, and to start collecting first data on the behaviour of fish around drifting FADs.