Cooperative Fish and Wildlife Research Units Program: Texas
Education, Research and Technical Assistance for Managing Our Natural Resources

Golden algae Prymnesium parvum is a unicellular haptophyte algae which may be a recent arrival to Texas, first identified from the Pecos River in 1985. This species is capable of producing and releasing the toxin prymnesin during bloom events resulting in ecologically and economically devastating fish kills. Golden algae is responsible for a series of harmful algae blooms over the past 25 years resulting in fish kill events with a financial impact to state and local economies of millions of dollars. While not insignificant, this ecological and economic damage would seem to have had the potential to be much worse as golden algae is tolerant of a wide range of environmental conditions and thus is capable of thriving in freshwater, estuarine and marine habitats. Yet the species has remained largely confined to relatively small portions of the Brazos, Colorado, and Red River basins. The biotic and abiotic conditions enabling golden algae to successfully colonize new habitat and result in a bloom are largely unknown making it difficult to predict the future spread and potential impact of the species. For example, it is possible that conditions in areas that have thus far not experienced golden algae blooms are not conducive to its growth due to current temperature or salinity regimes, lack of essential trace elements or micronutrients, or the presence of phytoplankton species that are superior competitors under local conditions. These dynamics must be clearly understood to identify areas vulnerable to golden algae blooms and properly allocate resources for monitoring and response. Furthermore, alterations of the abiotic environment driven by climate change or other anthropogenic disturbances have the potential to affect the growth of golden algae and the outcome of competitive interactions with other species. An assessment of golden algae growth under a range of conditions consistent with climate model predictions is necessary to identify areas that may become vulnerable to invasion in the future.