Our approach will include sampling a wide range of habitats and environmental conditions throughout the middle and lower Pecos River basin, across an 18 month time-span to account for seasonal and phenological events. We will utilize a suite of univariate and multivariate statistical techniques to relate occurrence and density of golden alga to environmental factors and other co-occurring organisms. The proposed research will benefit managers of the Pecos River, of its associated reservoirs and unique habitats (sinkholes on the Bottomless Lakes State Park and Bitter Lakes National Wildlife Refuge), and of its resident aquatic biota by identifying specific water quality attributes that promote golden alga bloom development and potential toxicity to several aquatic species of concern. More specifically, the information obtained may be useful to the management of surface water and its associated watershed either to prevent or to mitigate conditions that result in toxic algal blooms. Additional benefits will be to the recreational users of these systems, including anglers utilizing sport fisheries in the region.