Aquariums allow us a minimal glance into the colorful underwater lives of fish species around the world. However, we don’t often give a lot of thought to what fish actually sound like underwater – at least, I don’t, unless you count Ellen Degeneres’ characteristic voicing of Dory in Finding Nemo. Steve Simpson, associate professor at the University of Exeter in the U.K., does. Simpson and his colleagues study the soundscape of British seas, and are particularly interested in how the sounds fish make affect their ability to attract mates.

Simpson’s most recent research, presented at the National Environment Research Council’s “Into the Blue” showcase and detailed in a recent university press release, reveals a surprising fact about our friends with fins: fish that live in different areas of the water have different “accents” that allow them to communicate with one another – and with future mates. He says recordings of American cod are extremely different from their European counterparts. While American cod make “a staccato, banging, bop bop bop sound,” European cod make more of a “deep, rumbling growling.”

Simpson likens these noises to “love songs” the male fish sing to their potential female mates. He’s concerned that noise pollution from speed boats or other ships may negatively affect the cod’s ability to serenade future lovers.

“Fish produce a variety of sounds, sometimes using their swim bladders to make thumping and rumblings sounds, to establish territories, raise the alarm, and attract mates. In noisy places, the ‘gossip’ essential to their society is being drowned out,” Simpson said in the news release.

Of even greater concern is the warming of ocean temperatures due to climate change, which is causing many species of fish to migrate to cooler waters. If fish from different areas are not able to understand one another’s accents, this could create a barrier for successful future reproduction.

“A whole set of challenges could arise if females show a particular preference for the kinds of love songs they like,” Simpson said in an ABC News article. “They could struggle to breed and integrate.”

What happens then? These changes are still in progress, so scientists aren’t sure. But understanding more about the cods’ characteristic accents is an important first step.