Tom Miller, director of the Lamar Bruni Vergara Environmental Science Center (LBVESC) spent his childhood hunting for mussels on the St. Croix River in Afton, Minnesota.
Miller, now a longtime Laredo resident who has taught aquatic biology courses for the last 17 years at Laredo Community College, has conducted studies of the Texas Hornshell mussel, which is being proposed for inclusion to the Federal endangered species list by U.S. Fish and Wildlife Services.
His interest in mussels was rekindled when the Texas Academy of Science announced in 2001 that there were no mussels left in the Río Grande.
“I had some on display at the LBVESC,” Miller recalled. “I found the first live Hornshells mussels in the Devil’s River and at Las Palmas Park in Laredo, as well as other species that hadn’t been seen in decades. My first surveys were done without knowing the Hornshell’s habitat very well, but on a birding trip by canoe I came across about 200 Hornshells on the riverbanks at La Bota Ranch and then larger populations north of Bridge 4 to Colombia,” he said.
“We have found none south of the Zacate Creek Sewage Treatment Plant, perhaps because the water there is overpowered by sediment, chlorine, and the raw sewage outfalls from Nuevo Laredo,” Miller said.
The Texas Hornshell and other mussels are food for raccoons; river otters, which Miller has sighted past La Bota Ranch; and muskrats.
Miller elaborated on adverse upriver conditions at Eagle Pass. The Río Grande’s flow, he said, has been reduced to “next to nothing” by the Depression-era WPA-constructed irrigation canals that divert water to hay fields and pecan groves. The diminished flow adds sediment to what little water does move.
He noted, too, that the water quality of the Río Grande has long been affected by the upriver raw sewage outfalls of Ciudad Acuña and Piedras Negras, and that centuries of agricultural use along the Pecos River have contributed to the salinity of the Río Grande.
“There are no mussels in that stretch of the river,” he said.
Miller said that prior to 1996, there wasn’t much concern about water quality in the Río Grande. It was citizens who informed the Texas Parks and Wildlife Department (TPWD) about dwindling mussel populations, he continued.
Francis Atwell, outreach coordinator of Rep. Henry Cuellar’s office, visited with Tom Miller of the Lamar Bruni Vergara Environmental Science Center. They are pictured at the U.S. Fish and Wildlife hearing on the listing of the Texas Hornshell mussel as an endangered species.
“The research was telling us that the presence of certain freshwater mussels were an indicator of good water quality. The state began to take a greater interest in the river in the years between 1996 and 2001. We are 30 years behind in researching water life on this river. There are 75 species of mussels already declared endangered nationally,” he said, adding that TPWD biologist Bob Howells turned his focus to the declining populations of mussels in freshwater ecosystems.
He credits Howells with putting an end to a $20-million-a-year harvest of Texas river mussels being shipped to Japan without regulation. The Japanese pearl industry used the single nuclei of a river mussel to make pearls, he said, adding that the state put a halt to the enterprise in 2000.
According to Miller, the state’s new interest in mussel populations drew academics, biologists, and funding to the river for additional studies.
Miller said that federal funding for studies came through TPWD.
From 2007 to 2013, Miller spent time on the Río Grande in kayaks, canoes, and an airboat collaborating with two biologists originally from Belarus, Drs. Lyuba Burlakova and Alexander Karateyev. The focus of their studies was the Texas Hornshell mussel.
The three published a 60-page paper entitled Long-term Changes in Unoniad mollusks and Fauna in the Río Grande: One of the USA’s Most Endangered Rivers.
Miller presented the paper at a 2013 TPWD symposium on freshwater mussels while Burlakova and Karateyev presented in Portugal. Karateyev, now a naturalized citizen, is the director of the Great Lakes Research Center.
According to Miller, additional funding became available for research, and by 2011, the state had accrued enough data to propose that 15 threatened mussel species be considered endangered. Miller said that U.S. Fish and Wildlife Services “has the final word.”
He said it would be “a whole new ballgame” if the Texas Hornshell mussel is designated as endangered.
