After tuna catching boats come back from the ocean, fishermen have to sell fish along the beach like before no more. They have a company buy their exploited tuna upon a supply chain. As agreed, the company refuses to buy their tuna if they fail to prove their legal exploitation. Thus, fishermen involved in the supply chain must strictly follow the exploitation rules.
Eight fishery trade unions, seventy fishery cooperatives have been established and more than 600 offshore boats built with 150 ones being involved in three chains of exploitation, purchase, process, consumption. Fishermen must be a part of the exploitation teams or groups to participate in the supply chain so that team or group members will remind each other of avoiding border violation during the exploitation.
Fishermen must state their gross exploitation commensurately to the logbook. Then the Fishery control office will inform the purchasing company after confirmation. The best way to maintain the sustainability in fishery development is to build a supply chain where mutual benefit of both fishermen and company will boost them to prevent illegal fishing together.