Since the introduction of "dolphin-friendly" labeling, an increasing number of purse seine sets are now made on "free schools" unassociated with dolphins, as well as schools that associate with floating objects—another long-understood association that has grown in importance in tuna fisheries. The latter practice in particular has a major ecological impact because of the high proportion of bycatch, including manta rays, sea turtles, pelagic sharks, billfish, and other threatened marine species taken by setting nets around logs and other floating objects. Such tuna are often significantly smaller than the larger adult tuna associated with dolphins. The removal of huge numbers of juvenile yellowfin and bigeye tuna that have yet to reach breeding age has major potential consequences for tuna stocks worldwide.