A diverse body of recent research identifies collective ownership as a potentially better institution for common pool resource governance under some conditions than either private or state ownership. Extensive previous work analyzes the structure and functioning of successful collective ownership institutions, but there has been limited research examining the impact of stronger collective ownership rights on household welfare. Exploiting a natural experiment - in which some villages were exogenously included in a provincial level initiative to strengthen collective ownership rights over fisheries, while villages in a neighboring province were excluded - this article uses a unique dataset to examine the impact of collective fisheries ownership on household income and food consumption. Strengthening collective ownership rights increases household consumption of marine resources and decreases consumption of inferior canned-food substitutes, but does not increase monetary income. Income improvements that at first appear due to stronger collective ownership institutions can instead be attributed to NGO project support.