Then James Locascio, a doctoral student in marine science at the University of South Florida, rescued the city from financial folly. After reading the newspaper article, Mr. Locascio called a Council member just hours before a vote to appropriate the money. He explained that at 100 to 500 hertz, black drum mating calls travel at a low enough frequency and long enough wavelength to carry through sea walls, into the ground and through the construction of waterfront homes like the throbbing beat in a passing car.

Image Mating calls of the black drum can carry through sea walls and into homes. Click here to listen to the sounds of the black drum and other fish. Credit... Steven Senne/Associated Press

“Black drum have taken a liking to the canal system in Cape Coral,” Mr. Locascio said. “Their nightly booming is like a water drip torture that lasts for months.” ( Listen to the mating calls of the black drum and other fish sounds.)

At first residents wouldn’t buy it. “The most vocal and persistent complainers said that there was no way a fish could produce a sound that could be heard inside a house,” he recalled.

Mr. Locascio and David Mann, a marine biologist at the University of South Florida who is a bioacoustics expert, recruited these naysayers into a study by asking them to score noise levels and times in notebooks. “We took their data and plotted them with the fish sounds we had recorded with hydrophones under the water,” Mr. Locascio said. “Concordance was perfect.”

A similar situation unfolded two decades ago in Sausalito, Calif., when houseboaters were inundated with toadfish calls. The Marin Independent Journal said in an editorial, “We don’t believe for an instant that the drone keeping Sausalito houseboaters awake at night is caused by a bunch of romantic toadfish humming their version of the Indian Love Song.”