Mississippi Yields Record Turtle
Two state-record softshell turtles turned up this summer in a studyconducted by the DNR and U.S. Fish and Wildlife Servicein Weaver Bottoms, a large backwater of the Mississippi near Winona.
The more spectacular, for sheer size, was a spiny softshell (Apalone spinifera), discovered by Michael Pappas, a 30-year veteran of turtle research in the area, as he waded the shallows to trap turtles, which he weighs, measures, determines the sex of, and marks by drilling small holes along the edge of the shell. The turtles shell, flat and leathery, like a big moldy flapjack, measured 19.25 inches, beating the old state record by 1Ú2 inch. The turtle, a gravid female, weighed 22 pounds and carried 24 ping-pong-ball-size eggs. She was estimated to be 60 to 70 years old.
"It is phenomenal to find a female turtle of this size," according to Jaime Edwards, a DNR nongame wildlife specialist. The DNR Nongame Wildlife Program is helping fund Pappas work to learn more about the number of turtles and the abundance of various species in the area. "Because of the commercial trapping on the Mississippi River, large softshells are hard to come by."
Turtles are slow to mature. Females of most species begin to reproduce only after they are several years oldsometimes as old as 15. "It is important to retain the larger females in the population because they are the most reproductively active," Edwards said. "As a result, the adult females in turtle populations are critical to the long-term survival of each population."
This summer Pappas also captured a 12.5 inch, 7.5 pound smooth softshell (A. mutica), a state record for that species. That female also carried eggs. Smooth softshells, listed as a species of special concern in the state, are declining in number across Minnesota.
Both record turtles were released near where they were captured.
"In the Mississippi, of more than 2,500 turtles caught in the last two years in the Weaver Bottoms, only 1 percent were smooth softshells," Edwards said. "This indicates things are not looking good habitat-wise for the Weaver Bottoms, which should be crawling with smooth softshells." The smooth softshell prefers swift rivers with lots of aquatic vegetationa description of Weaver Bottoms in years gone by, but not today.
Flooded in the 1930s when the construction of Lock and No. Dam 5 backed up the river, Weaver Bottoms enjoyed a brief surge of productivity. Aquatic vegetation flourished and waterfowl fed in huge flocks. But in recent decades, silt has filled in the backwater. Increasingly turbid water has killed the vegetation. Muddy water has made life difficult for softshell turtle species, which feed by sight on small fish and other aquatic creatures, Edwards said.
The study of Weaver Bottoms, which began in 2001, will help the agencies make decisions on regulation changes and habitat management in and along the Mississippi River.