Shedd-Raised Endangered Turtles Off to Strong Start in Wild

Exit exam

Members of Shedd’s animal health team and Dan Thompson, the Forest Preserve District of DuPage County ecologist who oversees the head-start program, prepped the turtles for release, but also for tracking through their lives.

First, each was measured and weighed a last time. “We looked at them to make sure they’re healthy,” said Dr. Matt O’Connor, senior staff veterinarian. Indeed, they were. From a third-of-an-ounce hatchling, one of the larger yearlings had made a 10-fold increase in weight, to 3½ ounces, and almost doubled its shell length, from about 1¾ inches to 3 inches. Dan had brought Shedd’s new batch of hatchlings, and the size comparison best illustrates the advantages head starting gives the turtles. “You can see how much they’ve grown in a year,” Dr. Matt said. “It’s a little harder for a raccoon to eat a turtle that size.”

(In addition to habitat loss and high-speed traffic, threats to Blanding’s turtles include the large local raccoon population, which, unchecked by predators, consumes eggs and hatchlings.)

Next the turtles were microchipped. The grain-of-rice-sized subcutaneous transmitters are the same as those implanted in pets. “Except in a dog or cat,” Dr. Matt noted, “we put it between the shoulders. We can’t do that with a turtle, so we put it in front of one of the rear legs.”

Because a microchip can stop working, or, like a sliver, can work its way out through the skin, the veterinary team also utilized the predigital method of marking turtles: filing small V-shaped notches in the rims, or marginal scutes, of their shells. A unique code of three or four notches tells each turtle’s story: its head-start origin, ID number, year of hatching and release date.

The send-off

Around noon, the release team—Dr. Matt, two veterinary technicians, two aquarists, Dan and another ecologist from the DuPage Forest Preserve District—arrived at the first of two sites, a marsh on the western edge of the county.

One task remained: The original white ID numbers assigned to the hatchlings and inked on their carapaces, or top shells, had to be blacked out with a nontoxic marker so that the turtles wouldn’t be noticed—and perhaps illegally pocketed—by anyone visiting their marshes.

The 23 yearlings, divided among four buckets for release, are the offspring of eight females that reside in the two marsh release sites. Dr. Matt explained, “In accordance with state regulations, we have to release the turtles where the moms are from to keep the genetics where they are at this point.”

He continued, “Once we were in a location, we released them along the edges of the marsh, where there’s a lot of vegetation—cattails, reeds, sedges—that they could climb on and hide under.” That involved slogging through knee-deep water over a bottom of thick mud—perfect terrain for the turtles, but goopy footing for people, and a few staffers came close to falling in as they moved around the marshes gently distributing the turtles.

Farewell, for now… and hello!

“Being involved in this kind of program and partnership is extremely rewarding,” Dr. Matt said. “After nurturing the hatchlings and watching them grow for a year, you release them into the wild, and they immediately know what to do, whether it’s dive into the mud or paddle off as fast as they can. You might see them surface for breath a few minutes later, and then they disappear into the marsh. We get to see the fruits of our labors.”

Those fruits will multiply as the turtles do. The program, begun in 1996, has already produced a second generation of head-started turtles. In 14 to 20 years, the first offspring of females from the class of 2019 may be part of the long-term head-start collaboration. While Blanding’s turtles mature slowly, they have the potential to live, and reproduce, for 80 years.

“For some of the people involved, it’s a little bittersweet to say goodbye to the turtles they’ve gotten to know over the last year,” Dr. Matt said. “But then it’s exciting to welcome a new group of hatchlings and get to do it all over again as Shedd Aquarium helps protect a local endangered species.”

—Karen Furnweger, web editor