Zach Cinquegrana, a member of teacher William Brew’s aquatic ecology class at Coventry High School, watches a camera-equipped robot in a test run at the West Warwick YMCA this week. The unit needs some tweaking.

The Providence Journal / Kathy Borchers

COVENTRY — Tiogue Lake is 215 acres of sparkling depths brimming with carp and pickerel that share their habitat with families of corbicula fluminea.

More commonly known as Asian clams, these freshwater mollusks are not a direct hazard to human beings. But they are harmful to the environment: they are known to clog up underwater power plant water-intakes and are a threat to other aquatic species because they rob the water of its nutrients, oxygen and food particles.

The Asian clam’s impact on the environment is a topic for Coventry High School students in William Brew’s aquatic ecology class. Starting later this spring, they will conduct a population study of the invasive mollusks and map out their beds throughout the lake.

Last week, 10 students from Brew’s class met at the YMCA in West Warwick to test out a piece of equipment for their study –– a R.O.V. –– or remote-operated vehicle. The R.O.V. is an aquatic robot devised by scientists at the National Oceanic and Atmospheric Administration for use by elementary and secondary schools. It makes the robot available in kit form — charging for some components and lending others.

Brew obtained a $500 grant from two nonprofit agencies, Rhode Island Living Democracy and KIDS Civic Action Network, which assist community-based service projects for students, toward acquiring the kit.

The plastic-framed unit is powered by an electric motor, and its movement is controlled via a tether. It carries a global positioning system for tracking and a video camera that transmits what it sees. The students envision it cruising just above the lake bottom, scanning for the clams.

“Any invasive or non-native species starts to take up the nutrients from the native species. They can be very disruptive to the biodiversity of the lake and the entire ecosystem,” Brew said. He hopes to have his students study the population fluctuations in the lake yearly and research possible ways to manage its growth.

Last week’s test in the Y’s pool was, uh, inconclusive.

Zachary Cinquegrana, 16, an 11th-grader in Brew’s class, went into the water prepared to retrieve the robot from the pool’s bottom if necessary.

But the electric motor refused to start, and the robot simply floated languidly on the surface.

As the students sat around waiting for Brew to figure out what went wrong, some, including Jessica Rogers, mused on what they hope to learn. (Ultimately, the teacher determined that a tiny fuse had blown.)

“Technology is really my thing and trying to figure things out,” said Rogers, 18, a senior who said she is in interested in environmental law. “What we are going to study is this invasive species and where it comes from.”

The R.O.V., still awaiting conclusive “sea trials,” is key to the population study.

The Asian clam is tiny; a mature one rarely exceeds the size of a nickel. The clam has both female and male reproductive parts. It can spawn rapidly in moderately warm water temperature, releasing up to 70,000 babies in a year.

Native to Southeast Asia, it was introduced to North America’s West Coast in the mid-1920s by Chinese immigrants. By the 1970s, the clam had spread to most of the Mississippi Basin, the Gulf Coast and eastern seaboard.

Biologists discovered it in Delaware in 1972 and it continued north — to New Jersey and Long Island — within the ensuing decade. It was found in the lower Connecticut River in the early 1990s.

The first one was discovered in Tiogue Lake about five years ago, probably carried there on a boat hull or discarded there with someone’s aquarium water, Brew said.

lsparks@projo.com