Community Impact –
The San Marcos River is home to some of the most biologically diverse aquatic ecosystems in the southwestern United States, harboring multiple threatened and endangered species, according to the San Marcos River Foundation.
And now researchers at Texas State University fear that an “increasingly severe” parasite problem in the San Marcos and Comal rivers could threaten the fish that live in them, including those that are already endangered—namely the fountain darter.
Haplorchis pumillio, the parasite, first arrived in the rivers by way of an invasive Asian snail, which is known to host more parasites than any snail in the world. David Huffman, a parasitologist of Texas State’s biology department, said the parasite was brought to America with the aquarium trade in the mid-20th century; the snail made its way into the rivers as a result of people dumping their aquariums into the water.
Huffman, who has done extensive research on the Haplorchis parasite and is a member of the Texas Invasive Species Institute, told Community Impact Newspaper that the larvae of the parasitic worm are known to penetrate the skin of fish and cause trauma and inflammation, which affects their ability to swim.