The development of aquaculture in the Agno-Pantal-Calmay River Estuary system of Dagupan City, Pangasinan Province in the Philippines is reviewed. Traditionally, extensive pond culture of milkfish, Chanos chanos and penaeid shrimp was practiced along with culture of mangrove oysters, Crassostrea iredalei, in adjacent estuarine waterways. Netpen culture of serranid groupers in the estuaries began in the early 1980s, followed by intensive fish pen culture of milkfish in the late 1980s. Over intensification of finfish aquaculture led to hyper eutrophication and fish kills beginning in 1996. Official governmental response to the fish kills is reported, and recommendations to prevent future fish kills based upon aquaculture carrying capacity considerations are offered.