Rocky students study river turtles for exposure to harmful chemicals, population size
BIGHORN RIVER — Prehistoric-looking creatures swimming in the rivers of Eastern Montana were thrust into the limelight by budding Rocky Mountain College researchers this summer.
“They’re actually really cool,” said Andrhea Massey, 20, as she held a large hissing snapping turtle firmly by its shell. “They look like dinosaurs. The spikes on their tails are really impressive. Look at their claws.”
Massey and fellow student Gabriel Aponte, 22, were leading the dirty work of weighing, measuring and tagging snapping and spiny soft-shelled turtles on the Bighorn River recently, the end of their summer field study of the little-appreciated turtle species. Their baited live trapping also included work on portions of the Clarks Fork of the Yellowstone River, the Yellowstone River from Billings downstream, Pryor and Razor creeks.
Tag, you’re it
The work is the second year of a study by the Yellowstone River Research Center at Rocky Mountain College, which has been assisted by Montana Fish, Wildlife and Parks. Last year’s work included the Musselshell River.
Through the study Kayhan Ostovar, an associate professor of biology and environmental science at Rocky who has guided the work, is hoping to learn several things. One is a comparison of the difference in the accumulation of toxins in the turtle’s blood — things like arsenic, mercury and lead — between the rivers. Are turtles in the industrialized Yellowstone River exposed to more harmful chemicals than turtles in more rural rivers like the Musselshell or Clarks Fork?
By tagging and with eventual recapture, the study could also provide a ballpark figure on the number of turtles in the rivers and streams. This summer the group tagged more than 300 soft-shelled and 25 snapping turtles.
The tagging can also show how far the turtles travel. Previous studies have shown the amphibians aren’t big migrators, especially the soft-shelled turtles that don’t move across land. Tag monitoring could also show connectivity between the river populations, which can have an effect on their sustainability. Are the animals moving around irrigation dams, or are they fairly isolated by such manmade structures? Isolation can lead to a lack of genetic diversity and a resulting susceptibility to diseases.
The researchers can also examine the difference between turtles in the relatively free-flowing Yellowstone River compared to the dammed and regulated flows of the Bighorn River.
For the most part, Montana’s river turtles live in obscurity.
“This is about as far north and west as both species live,” Ostovar said. “Both are species of concern in Montana that are vulnerable to overharvest.”
In the south, where the species are more common, turtles are often caught to eat. Ostovar said while visiting San Francisco’s Chinatown he saw turtles for sale at $13 a pound. In Montana, however, it’s rare to hear of someone dining on turtle or purposely setting out to catch them.
Montana Fish, Wildlife and Parks conducted a five-year study beginning in 2004 that ruled out the turtles’ presence in some waters, like the Missouri River below Fort Peck Dam and the Yellowstone River from Sidney downstream to its confluence with the Missouri. The study found the farthest that a tagged soft-shelled turtle moved was 10 miles. Montana State University student Brian Tornabene conducted a study on soft-shelled turtles in the upper Missouri River Breaks between 2010-13 for his master’s thesis and helped out on the Yellowstone research, as well.
Massey and Aponte are lucky that they get to conduct field work on the creatures as undergraduates, something that’s uncommon in many colleges and part of what attracted them to the Billings school from their homes in faraway Texas and Venezuela, respectively.
“We’re helping to train that next generation of conservationists,” Ostovar said.