The standards form the basis of policies utilized by the largest tuna producers in the world. It is required for approval and monitoring by Earth Island Institute. In order for tuna to be considered "Dolphin Safe", it must meet the following standards: No intentional chasing, netting or encirclement of dolphins during an entire tuna fishing trip; No use of drift gill nets to catch tuna; No accidental killing or serious injury to any dolphins during net sets; No mixing of dolphin-safe and dolphin-deadly tuna in individual boat wells (for accidental kill of dolphins), or in processing or storage facilities; and Each trip in the Eastern Tropical Pacific Ocean (ETP) by vessels 400 gross tons and above must have an independent observer on board attesting to the compliance with points (1) through (4) above. By agreement between Earth Island Institute and the participants in "Dolphin Safe" fishing operations: All processing, storage, and transshipment facilities and procurement records related to the purchase, processing, storage, transport, and sale of tuna must be made available for independent monitoring. Companies listed as "Dolphin Safe" must maintain "Dolphin Safe" policies approved by Earth Island Institute and apply them to all international aspects of their operations and related subsidiaries. Further, Earth Island Institute and the 85-member Dolphin Safe/Fair Trade Campaign strongly encourage tuna fishermen and tuna companies to work to reduce bycatch of non-target species and to release alive, to the maximum extent feasible, any non-target species caught in purse seine nets. These "Dolphin Safe" standards were developed in 1990 by Earth Island Institute and the H.J. Heinz Corporation (StarKist Tuna); endorsed by the U.S. Tuna Foundation, Chicken of the Sea, and Bumble Bee Tuna; and have been adopted by approximately 300 tuna companies, canneries, brokers, import associations, retail store, and restaurant chains around the globe. By way of background, in 1997, only 2.9% of the world's tuna supply was caught by chasing and setting nets on dolphins. More than 90% of the world's canned tuna market has pledged to buy and sell only "Dolphin Safe" tuna in accordance with Earth Island's "Dolphin Safe" standards. As a result of the "Dolphin Safe" commitment by tuna companies, dolphin mortality has dropped by more than 97% in the past ten years.