Mafia Island Marine Park is very special. With hard work, they have succeded in involving the local community. Fishermen had allmost emptied the sea and used poison and explosives. They had nothing to loose. The Park administration made the plan, preserving the mangrove, and instructed the fishermen where, how much, how and only with delivered type of nets. Slowly the fish returned, and the catch was slowly comming back. The fishermen realized that only substantional behaviour could make them survive.