Why Scientists Photograph Freshwater Mussels

Freshwater mussels can seem dull. They look like river rocks, barely move in a lifetime, aren't the mussels most Americans eat, and usually hold no pearl. But beneath the shell is an animal that filters contaminants from water, recycles nutrients and even records climate data. This page draws on an article from the "Picture This" section of the National Park Service's Park Science magazine (Winter 2024–25).

In trouble

Freshwater mussels are among the most imperiled animals on Earth: in North America, nearly two-thirds of species are at risk, mainly from pollution and from habitat loss caused by dams, mining and other human activity.

Diversity is highest in the southeastern United States, thanks to the region's origins and geology. Big South Fork National River and Recreation Area, in Kentucky and Tennessee, has some of the most diverse native mussel communities in the world. Even there, mussels face threats that begin outside the park: fragmented habitat, contaminants and climate change.

Rearing and returning mussels

The National Park Service's Appalachian Highlands Network is working with parks such as Big South Fork and with outside partners, including the State of Kentucky's Center for Mollusk Conservation, to help the most at-risk populations through hatchery rearing, restoration and reintroduction.

Why photographs

Photographing mussels is part of the work. Pictures record a hidden world and help scientists follow how species fare under changing conditions, across sites and over years. The article's featured image, by the Center for Mollusk Conservation's director, a malacologist (a scientist who studies mollusks), shows a scientist taking one last photo of a mussel before returning it to the streambed; a green tag on its shell shows it began life in the lab.

The goal

The scientists hope that after about a decade of restoration, mussel populations may be able to sustain themselves. That could make all the difference for species found only in this area — and healthier mussels mean healthier rivers for wildlife and people.

Sources

• National Park Service, Park Science 39(1), Winter 2024–25: "Remarkable, Boring Mussels: Why Scientists Take Photos of Them Anyway," by Olivia Porter, Scientists in Parks intern with the NPS Inventory and Monitoring Division.