By Don Lyman
The Boston Globe, May 25, 2019
Above: It’s lunchtime for the cooters, as Isabella Bartlett spreads mixed greens on the surface of the turtles’ pool.DON LYMAN
In a warm, humid greenhouse at Bristol County Agricultural High School in Dighton, senior Andrew Flory swirled a dipnet with a long wooden handle through the water of a 30-inch-deep, 460-gallon aquaculture pool. He scooped up several juvenile Northern Red-bellied Cooters. His classmates — Serena Cornell, Mia Slater, and Isabella Bartlett — plucked the turtles from the net and counted them as they transferred them to a large plastic tub. After a few minutes, all 30 turtles were rounded up, ready to be weighed and measured. The students were working on the Northern Red-bellied Cooter Head-starting Program, overseen by the Massachusetts Division of Fisheries and Wildlife’s Natural Heritage and Endangered Species Program and the US Fish and Wildlife Service. In the late 1970s, US officials estimated there were only about 200 left in a dozen ponds in Plymouth County. This small, isolated population is hundreds of miles away from the main Red-bellied Cooter population, which extends from southern New Jersey to North Carolina. The federal government put the Massachusetts population of cooters on the endangered species list in 1980, and state and federal wildlife officials stepped in to help restore healthy populations. Partnering with organizations such as zoos and aquariums, as well as with schools, led to students raising baby Red-bellied Cooters for later release into the wild.
The process, called head-starting, allows hatchling turtles to grow to the size of a 3- or 4-year-olds during the school year, because they’re kept in a warm environment where they remain active and feeding, as opposed to being inactive throughout the winter like their wild counterparts.
Right: A hatchling Northern Red-bellied Cooter in Plymouth, Mass.MIKE JONES
The head-started turtles’ larger size makes them less vulnerable to predators, such as largemouth bass and great blue herons, when the turtles are released in the spring, and increases their chances of surviving to adulthood. Toward the end of the school year, the students give the head-started cooters to Massachusetts wildlife officials to be released.
There are 23 institutions participating in the head-starting program, including about a dozen schools, according to Mike Jones, state herpetologist with the Massachusetts Natural Heritage and Endangered Species Program. “As a result of the head-starting effort, Red-bellied Cooters are now found well beyond the immediate vicinity of the towns of Plymouth and Carver in other areas of southeastern Massachusetts,” Jones said in an e-mail. According to a fact sheet from the Natural Heritage and Endangered Species Program, more than 4,000 head-started Red-bellied Cooters were released at more than 30 sites in southeastern Massachusetts from 1984 to 2016, with an estimated 95 percent annual survival rate in many ponds. Red-bellied Cooters are named for the color of the underside of their shells. They can grow to 13.5 inches long, and weigh more than 12 pounds, making them the second-largest freshwater turtle species in Massachusetts, after the snapping turtle. “There’s really no other species quite like it in the state,” said Jones. “If you’ve seen this turtle in the wild in Plymouth County, you won’t forget it — they are a striking, elegant, unique member of our native fauna.” Jones said the Massachusetts population qualified for federal endangered species status as a “Distinct Population Segment” of the larger species distribution. Jones said Massachusetts listed the Red-bellied Cooter as endangered on the state level in 1990. “It’s the only population of Red-bellied Cooters this far north,” said Flory. “That’s kind of cool. It’s kind of important to keep that alive.”
In the wild, the turtles face a variety of threats. Some are struck by cars as they cross roads, and property development has destroyed or reduced good nesting habitat. Predators, such as coyotes, foxes, skunks, and raccoons, dig up turtle nests and eat the eggs, according to Jared Green, wildlife refuge specialist for the USFWS’s Eastern Massachusetts National Wildlife Refuge Complex. If biologists locate turtle nests, they protect them by putting wire mesh cages over the nest sites. Cooter hatchlings are not much bigger than a quarter when they hatch, and are also vulnerable to predators. The students in Dighton weigh and measure the turtles every Friday. Each turtle has a number painted on its shell so it can be easily identified. Cornell lifts the turtles out of the plastic bin, and weighs them on a digital scale. Bartlett measures the length of the top of the turtles’ shells – called the carapace – using calipers. Slater records the data as Cornell and Bartlett call out the turtles’ weights and lengths. “The turtles run off the scale sometimes when they’re getting weighed, so we weigh them on their back if we have to,” said Bartlett. “The average cooter arrives weighing 9 grams and leaves weighing 45 grams,” said Brian Bastarache, who supervises the red-bellied cooter project as chair of the Natural Resource Management Department at BCAHS. The process flows with assembly line efficiency, and in about 20 minutes all the turtles are weighed, measured and returned to their holding tank. Now it’s time for the turtles’ lunch – bags of leftover greens donated by Hannaford’s Supermarket in nearby Taunton, which the students spread onto the surface of the turtles’ 6-foot-wide pool.
Although cooters feed mainly on plants, they also are given a small amount of commercial fish food about once a month to round out their diet and provide any nutrients that may be missing. While generally considered a valuable conservation tool, some biologists are critical of head-starting, said Bastarache. “They say head-started turtles won’t know how to survive in the wild,” Bastarache said. “I disagree, because turtles don’t learn from their parents, like birds and mammals do, and nine months of head-starting isn’t going to wipe out millions of years of evolution.” Green said another potential downside of head-starting is the possible introduction of disease into wild turtle populations from turtles raised in captivity. But, he said head-starting organizations follow strict protocols that limit the likelihood of this occurring. Bastarache said by the end of this year his students will have raised and released 193 red-bellied cooters since Bristol County Agricultural High School first got involved with the project in 2011. The students said they’ve gained a lot from working on the project, including valuable work experience and doing good for the environment. “The turtles were the size of a quarter when they first hatched,” said Slater. “We gave them a chance of surviving longer than they would in the wild.”
Above: A hatchling Northern Red-bellied Cooter in Plymouth, Mass.MIKE JONES
Comments