The impacts of banning wild spat collection are crucial for the future development of the Zhikong scallop fishery. Failure to the quantitative analysis of economic impacts obstructs the understanding of policy performance. Using key parameters extracted from the data and information through field research, we estimate the financial losses in spat collection, mariculture, and processing sectors. Our results show that the local ban should spark a chain reaction on the national Zhikong scallop fishery and potentially cause substantial economic consequences. The decreasing profitability and growing negative externalities of traditional mariculture are the main reasons for the local government to overhaul its marine development strategy. These findings have implications for some problems in the current marine management system or, from a more positive perspective, the crisis of the Zhikong scallop fishery providing China an opportunity to accelerate reforms for sustainable mariculture.