Blood cockle (Anadara granosa) farming has become one of the most economically important coastal aquaculture activities on the east coast of Sumatra, Indonesia. Despite its significant contribution to local livelihoods, exports, and regional economic growth, the rapid expansion of the industry has generated increasing concerns regarding coastal governance, legal certainty, and market concentration. This study was aimed to analyze the legal and monopoly issues associated with blood cockle farming and their implications for sustainable coastal resource management. A qualitative case study approach was employed using field observations, stakeholder interviews, document analysis, and review of relevant legislation governing coastal areas, fisheries, and marine spatial planning. The findings reveal that blood cockle cultivation is predominantly conducted on state-owned intertidal mudflats where formal tenure rights are generally absent. Ownership claims are largely based on customary occupation and informal local agreements, resulting in frequent disputes over cultivation boundaries, unauthorized harvesting, and restricted public access to coastal resources. The study further identifies overlapping institutional authority and inconsistent regulatory implementation as major obstacles to effective governance. Market analysis indicates increasing concentration of productive farming areas, capital ownership, and export marketing networks in the hands of a limited number of investors and collectors. This condition creates localized monopoly over cultivation grounds and oligopsonistic market structures that weaken the bargaining power of small-scale farmers and increase their dependence on dominant buyers. Consequently, economic benefits are distributed unevenly, while access to productive coastal resources becomes increasingly restricted for traditional fishing communities. The study concludes that sustainable development of blood cockle farming requires integrated coastal governance based on transparent tenure allocation, strengthened legal enforcement, equitable market institutions, and participatory resource management. Such institutional reforms are essential to balance economic development with social equity, environmental sustainability, and long-term resilience of Indonesia's coastal aquaculture sector.
