This study explored the experiences of local community members living in and around Taal Lake, a protected area that is also the exclusive home of the only freshwater sardine in the world, the tawilis. It used the grounded theory approach to understand the social psychological dimensions of biodiversity conservation in the Philippines. Data from participant observation, archival resources, and semi-structured in-depth interviews were gathered, coded, and analyzed to arrive at a data-driven model of the process of a local community's valuing and protecting a threatened species and its habitat. The inseparability of the tawilis and the Taal Lake emerged as the core category. Results also show that the key categories (a) mental model and conceptual knowledge, (b) proximity to and dependence on the lake, (c) economic factors, and (d) governance influence the valuing and protection of the tawilis and the Taal Lake.Theoretical and practical implications for crafting conservation initiatives are discussed.