Nebraskaland

50 NEBRASKAland • JULY 2015 consisted of representatives from the fish and game agencies of the Missouri River Basin, but in the end, only Nebraska and Montana took on the project, and only Nebraska continues the study today. Nebraska biologists knew the importance of determining what population changes might be occurring in the Missouri River system. "Reptiles and amphibians are good indicators of ecosystem conditions," said Gerald Mestl, the Commission's Missouri River Program manager. "They have long life spans and they respond to changing environmental conditions through reproductive success." Turtle surveys are another tool, along with fish population and water quality surveys, to look at the health of the river. Originally a wildlife division project, the study was handed over to the Missouri River Program, the same team that handles the pallid sturgeon broodstock collection effort each spring. In addition to bringing together the wildlife and fisheries divisions, the Commission had two partners in the study. The National Park Service, which manages the upper two reaches as the Missouri National Recreational River, provided the Commission with staffing. And the United States Army Corps of Engineers provided the passive integrated transponder (PIT) tags that help researchers track turtle movements. A PIT tag is a small, glass- encapsulated tag that is inserted into a turtle's hind leg for tracking – the same technology biologists use to tag pallid sturgeons. PIT tags, put simply, are the same tags often used in pets. They are implanted and therefore cannot fall off. Sampling The project finished its second round of sampling last summer; each round spans three years. The first round of sampling ran from 2005 to 2007 and the second from 2012 to 2014. The team will take a break and then conduct another round of sampling in a few years. The Commission does not have the resources to conduct sampling every year, yet this approach will still allow biologists to see trends and changes in turtle populations, said Mestl. Sampling includes four reaches: the unchannelized section above Lewis and Clark Reservoir by Niobrara, the reach below Gavins Point Dam down to Ponca/Sioux City, and the two channelized reaches above and below the Platte River, Blair and Brownville. Each section requires four days of sampling, Monday through Thursday. On Monday, traps are set out, baited with pieces of common carp, and habitat measurements are recorded at each trap, including location, habitat features, water temperature, oxygen level, turbidity, water depth, flow and much more. Traps – specialized turtle hoop nets – are set at every river mile for 25 miles, ideally at the same locations each year. This is easy to do on the channelized river, "but up on the two unchannelized sections, the river changes all the time. The channel can be on one side or the other every year," said Ryan Ruskamp, a Commission biologist who is the lead on the project. On Tuesday, the team comes back to check traps, re-bait and process any turtles caught. All turtles are scanned with a special reader to see if they have been tagged; recaptures account for 10 percent of total catch to date. Then length, weight and sex are recorded before release. This process repeats until Thursday when all traps are pulled for transfer to the next segment of river. The team starts at the segment by Niobrara almost every year and makes it way downriver. De-listing the False Map So far, the team has handled 3,056 turtles in six years, and the study experienced a major achievement in just its first round. One of the big questions the Commission wanted to answer first was the status of the false map turtle in the river. A popular pet species, false maps were placed on the Nebraska Heritage Program list as imperiled in the state in 1989. However, in later years, that status was questioned. "Those of us who have been on the river a long time have always wondered about the status of false maps. Because if you sit on the river, and you got 30 heads looking at you, it's hard to think that the species is close to disappearing," said Mestl. "Some of us questioned that status, but none of us knew enough about it to make specific recommendations. So for us, this project is giving us some perspective on the turtles in 385 miles of the Missouri River." In 2010, data allowed the Commission to remove false map turtles from the Nebraska Heritage Program list. The team found that After this false map turtle was scanned with a special reader and determined that it was not a recapture, a biologist inserts a passive integrated transponder (PIT) tag into its hind left leg for future reference.

• Cover