Editor’s note: This is one in a series of articles about students involved in cool research, scholarly and creative activities during their summer break from classes.
Lisa Isabella-Valenzi has plenty of fond childhood memories of fishing with her father, so she is pleased to spend most of her summer studying ways to get rid of invasive species that are robbing many area anglers of their favourite pastime.
A second-year master’s student in Biological Sciences, Isabella-Valenzi is researching the effectiveness of snaring round gobies in the Detroit River with an acoustic trapping system.
“My record for one trap was 27 gobies,” she said of the system, which consists of a plastic mesh trap with an underwater speaker in it. The speakers transmit recordings of the sounds made by male species of the small fish when they’re luring females into their nests to lay their eggs, which will be fertilized later by the males. Her hope is that enticing reproductive females into those traps can help to reduce goby populations in the Great Lakes.
Round gobies are a small fish from Europe, transported here in the ballast tanks of ocean-going freighters. The first were found in the St. Clair River in 1990, and since arriving, their numbers have exploded. Besides reproducing more rapidly than native species and competing with them for finite sources of food, they feed on the eggs of such domestic fish as walleye, trout, small mouth bass and yellow perch, resulting in a decline in population of the species that sport anglers and commercial fisheries have typically relied upon.
“They’re really aggressive and they take up prime spawning space,” said Isabella-Valenzi, who studies under the tutelage of professor Dennis Higgs. “They don’t give the native population a chance to spawn and there’s been an obvious reduction in their numbers since the gobies showed up.”
Throughout the summer, Isabella-Valenzi and her colleagues Amanda Barkley and Dave Hoang–both fourth-year biology undergrads–have been setting traps on the tiny islands that were constructed in the river off the foot of McKee Park in Windsor’s west end to create a natural spawning ground for endangered species like lake sturgeon.
Around the islands, they set six traps that are hardwired to tackle boxes on land. In those boxes are 12-volt batteries, small car amps and mp3 devices that play one of two recordings of the males calling sounds. One is a field recording of a male goby in an established nest and called “the Janssen,” named after John Janssen, a professor at the University of Wisconsin. The other is “call-16” or “the drum call” which was recorded in an aquarium in Dr. Higgs’ lab.
So far the method is working and the students have caught hundreds of gobies. While they’re hopeful it might prove useful in reducing the species’ population–which has been estimated in the millions in the Great Lakes–they’re also realistic about the likelihood of totally eradicating them.
“You’re never going to get rid of them completely,” said Isabella-Valenzi, who also earned her undergraduate degree at the University of Windsor. “There’s just too many of them.”
After finishing her master’s degree this fall, Isabella-Valenzi hopes to find a job doing some sort of conservation work that will keep her outdoors, but in the meantime, she’s been thoroughly enjoying her summer project.
“I love it,” she said. “I just love being outside and I love doing field work.”