From the field

Fish Stories

Nathan Lovejoy untangles South America's diversity of fishes

Don Campbell
Nathan Lovejoy

Nathan Lovejoy’s fascination with tropical fish began when, as a child, he would page through reference books filled with the exotic animals of South America.

“I loved the detailed line drawings and was just blown away by the rich diversity of South American animals,” says Lovejoy, an associate professor in the Department of Biological Sciences.

His research at UTSC looks at patterns and processes of biodiversity, with emphasis on marine and freshwater fish from the tropics and especially electric fish from South America. His work often requires field trips to far-flung locations to gather samples.

A typical trip to South America is a complicated affair, always involving collaboration with international researchers. The collection work is usually done in remote tributaries of the Amazon River, and requires local guides to pilot the team there by boat. When hunting for electric fish, the researchers use a small amplifier that turns electric signals into a range of sounds. Some species produce a humming sound similar to a power station, while others sound like clicks.

Once Lovejoy’s team captures a fish in the field, they digitize and record its signal, while also taking a sample of the fish for genetic analysis. “We’re trying to collect as much biodiversity as possible, so we will go to as many different habitats as possible and also take recordings at different times of the day,” he says.

This type of field research has its share of perils. From getting stranded along the Amazon waiting for unpredictable boat taxis, to being boarded by armed coastguard patrols during night fishing trips,  to relying on overzealous rickshaw drivers for land transportation, Lovejoy has seen it all. He’s also been shocked several times by electric eels. It’s an experience not for the faint of heart, given an eel’s ability to produce 600 volts.

Back in the lab, Lovejoy’s team will sequence samples of fish DNA and use it to reconstruct an evolutionary tree for the species. Recently the team helped identify a new genus of electric fish, native to the rivers of a remote area of northern Guyana that has remained isolated from the rest of South America for more than 30 million years.

What motivates Lovejoy is finding the unique evolutionary pieces that make up the broader puzzle of how fish species came to be. His team looks at how electric fish developed their specialized mode of communication, why that ability has evolved over time, and its impact on mating. He’s especially interested in understanding the evolution of genes responsible for producing the electric signals.

“Intellectually it’s extremely satisfying to uncover these puzzles about why species are distributed the way they are across the landscape. For me,” he says, “trying to understand which animals are related to one another, and how, are all puzzles that are so enjoyable to solve.”