Human activity in the area of Tokyo Bay, Japan, has intensified significantly after World War II, pushed by a major transformation in the Japanese economic model that focused on heavy industrial development. Extensive land reclamation for the construction of infrastructure and an inflow of people in the bay led to marine pollution and, consequently, serious degradation of the local marine environment. As a result, the traditional fishing grounds of the area, which supported local livelihoods for generations, exhibited a radical decline, with the most important target species, mantis shrimp (Oratosquilla oratoria), almost disappearing. The local fisheries associations, with the support of the government, implemented several conservation and management initiatives in response to the fish stock change, and slowly the marine environment showed signs of improvement. However, the response of the natural system has not been fast enough, and the mantis shrimp stock has yet to recover. Faced with livelihood loss, the fishers have turned to other target species to maintain their income.