It is reported that the use of drifting fish aggregation devices (FADs), a technique employed increasingly for industrial-scale tuna fishery, could act as just such an ecological trap for these species. It is found that the tuna species caught from under the floating objects were less healthy. According to fishermen tuna aggregate under floating objects, such as lengths of old rope, pieces of wood, or even large marine mammals.
When the fishermen cast off floating rafts equipped with buoys which act as FADs and encircles the school of tuna that come to shelter under the FAD. The lower part of the net is tightened, enclosing the fish in a hemisphere large enough to entrap a mass of tuna. The research team work hard to find out if the large-scale use of drifting FADs could affect the migration patterns of tuna.
It is said that the drifting FADs appeared to act as super-stimuli, like strong magnets exerting a binding attraction that leads the tuna towards ecologically inappropriate waters with scarcer food supplies. The research shows that the biological effects observed indicated that it would be more reasonable to preclude deployment of drifting FADs near coasts where tuna juveniles aggregate.
