When a team of researchers recorded a low thundering underneath the surface of the Hudson River, they thought they were hearing the muffled rumble of trains.
A closer look, and listen, led to a much more interesting discovery: the thunder came from Atlantic sturgeon - an iconic and endangered species - spawning in the depths of the river.
"It's almost that you feel it more than you hear it," said Maija Niemistö, science educator with the New York State Water Resources Institute (NYSWRI), a joint research center with Cornell and the New York State Department of Environmental Conservation (NYSDEC). "You can hear these chirps and squirts and bubbles underwater, but this is a different experience entirely. These are ancient fish, and the thunder - it's almost like you're brought back in time, because they've been making this sound, communicating with each other, for millions of years. It's awe-inspiring."
In a collaboration between the NYSWRI, NYSDEC, the Cornell Lab of Ornithology's K. Lisa Yang Center for Conservation Bioacoustics, Cornell's Department of Natural Resources and the Environment (DNRE), and others, the team has confirmed the thunder of the Atlantic sturgeon for the first time, publishing the study in Endangered Species Research in 2025. That study was conducted in a known sturgeon spawning ground; this spring, the team placed additional underwater recorders in areas of suspected spawning, some of which are not protected.
