The Inland Fisheries Division of Texas Parks & Wildlife Department (TPWD) has been monitoring a noticeable lack of golden alga (Prymnesium parvum) in Texas rivers and lakes during recent months. The naturally-occurring alga is toxic to fish but is not known to affect other wildlife or people.
It was originally noted in the Pecos River in 1985, but has caused significant fish kills in the Brazos, Canadian, Colorado, and Red River basins as well. Algal blooms in 2003, including several large ones in fall and winter, killed an estimated 8,297,933 fish in the Brazos River system and an estimated 5,131,355 fish in the Colorado River basin.
But over this past winter, water samples have shown almost no golden alga. Department experts are hesitant to make any firm statements, but believe it is possible that heavier rains in 2007 produced flushes of freshwater in lakes and rivers that have inhibited algal blooms. Research by TPWD, universities and other partners is underway to better understand the organism.