Does the U.S. have the most fish species in North America?

Every ten years, scientists update a list originally compiled 76 years ago.

Research Need

With fish and wildlife management, it’s helpful to start with a baseline of what resources are available. It can be difficult to craft sustainable use strategies without a record of what was once available. 

Approximately every ten years since 1948, a group of scientists has published a list of the fish species in Canada, Mexico, and the United States.

The list has had eight editions, which provides plenty of material for comparisons of over time. It includes the names and classifications of species, whether they are native to the country in question, and whether they live in freshwater or saltwater.

What did they study?

A research team compared information across editions by country, habitat, and status as native or introduced. The team then compared the changes they had observed over the eight editions. 

What did they find?

There are 5,089 fish species in North America overall — a ninefold increase across the eight editions of the list: 3,821 in the United States, 3,261 in Mexico, and 1,254 in Canada.

This unprecedented increase in the number of species is likely due to changing requirements over the years for inclusion. (The original list included only well-known species in the United States and Canada.), More research and better methods also contributed to the list’s expansion.

In addition, fish are migrating and expanding their habitat ranges due to climate change, making them more easily discoverable.

Over 100 of the species are not native to the country where they now live — and other species are not native to the present areas within the same countries where they make their habitat.

The United States has the most species (84) that are not native to the country.

The United States (5th) and Mexico (8th) both rank among the top ten countries with the most diversity of fish species in the world.

What else did they find?

Unfortunately, five species since 1948 have gone extinct in nature (although three survive in captivity). One species formerly extinct in nature, however, has been successfully reintroduced into its natural habitat.

So what?

Although this list is extensive, it is by no means exhaustive. As research methods continue to develop and become more sophisticated, the Committee on Names of Fishes hopes to convert the list into an online format, which they can expand continually and provide publicly. This information could help readers better understand how climate change, overfishing, and other human-induced factors impact fish species in North America.

Reading

Schmitter-Soto, Juan J., Bemis, Katherine E., Dowling, Thomas E., Espinosa-Pérez, Héctor S., Findley, Lloyd T., et al., February 12, 2024. “How Many Fish Species Are in North America?” Ichthyology & Herpetology, 112(4) : 615-618. https://doi.org/10.1643/i2023047

The text from Hook, Line & Science is available to reprint and republish at no cost, but only in its entirety and with this attribution: Hook, Line & Science, courtesy of Scott Baker and Sara Mirabilio, North Carolina Sea Grant.