shellfish

In a new study, scientists Stewart Edie of the Smithsonian, Shan Huang of the University of Birmingham and colleagues drastically expanded the list of bivalve species, such as clams, oysters, mussels, scallops and their relatives, that humans are known to harvest and identified the traits that make these species prime targets for harvesting. They also discovered that some of these same traits have also made this group of shellfish less prone to extinction in the past and may protect these shellfish in the future. The authors flagged certain ocean regions, such as the east Atlantic and northeast and southeast Pacific, as areas of special concern for management and conservation. The research, published today in Nature Communications, finds that humans exploit some 801 species of bivalves. That figure adds 720 species to the 81 listed in the Food and Agriculture Organization of the United Nations’ Production Database, calling attention to the huge diversity of shellfish humans are known to harvest and use. These species live in a range of climates all over the world, with a wide range of temperatures. This adaptability promotes resilience against natural drivers of extinction. But at the same time, human demand for these species can put them and the ecosystems they are part of at greater risk of destruction. (credit: Brittany M. Hance and James D. Tiller, Smithsonian.)

WASHINGTON — Will seafood always be on the menu, or are these creatures likely to go extinct in our lifetime? For the first time, researchers have cataloged over 800 shellfish species that humans harvest, a list that could aid in future conservation. However, a collaborative team of British and American scientists has highlighted areas like the east Atlantic, and the northeast and southeast Pacific, as “special concern” zones, urging enhanced management and conservation efforts.

The study details that humans utilize 801 bivalve species — aquatic mollusks with hinged shells — including clams, oysters, mussels, and scallops. The researchers examined these bivalves, finding that their adaptability across diverse climates and temperature ranges makes them naturally resilient against extinction.

“We’re fortunate that the species we eat also tend to be more resistant to extinction,” says Dr. Stewart Edie, the curator of fossil bivalves at the Smithsonian Museum of Natural History, in a media release. “But humans can transform the environment in the geologic blink of an eye, and we have to sustainably manage these species so they are available for generations that will come after us.”

Four clams of differen shades of white and beige lay on a bed of dark green seaweed
Four bivalve species found along the Maine coast presented together in a bed of seaweed at low tide. Clockwise from the top right is a Northern quahog (Mercenaria mercenaria), an Eastern oyster (Crassostrea virginica), a steamer clam (Mya arenaria) and a blue mussel (Mytilus edulis). (credit: Danielle Hall, Smithsonian.)

Bivalve mollusks have sustained human diets for millennia and even served as building materials for ancient civilizations. For instance, in Estero Bay, Florida, the Calusa tribe once sustainably harvested billions of oysters, using their shells to construct monumental mounds.

“It is somewhat ironic that some of the traits that make bivalve species less vulnerable to extinction also make them far more attractive as a food source, being larger, and found in shallower waters in a wider geographical area,” says Dr. Shan Huang, a macro-ecologist at the University of Birmingham. “The human effect, therefore, can disproportionately remove the strong species.”

Conversely, history showcases episodes of bivalve overexploitation, especially by European colonizers and commercial fisheries. Such unsustainable practices have decimated oyster populations in various global locations, from Chesapeake Bay to Botany Bay in Australia.

Recognizing the absence of a comprehensive species list, Dr. Edie and colleagues amassed data on bivalves harvested by humans.

Illustration of nine different kinds of shellfish including clams, mussels, and oysters
Scientific illustration of exploited shellfish from several bivalve families (Pectinidae, Tellinidae, Cardiidae, Veneridae, Pinnidae, Spondylidae and Arcidae). Source: Encyclopaedia londinensis, or, Universal dictionary of arts, sciences, and literature… http://biodiversitylibrary.org/page/15915202 (credit: Image courtesy of Biodiversity Heritage Library.)

The research reveals that people often target bivalves that are large, thrive in shallow waters, span broad geographic areas, and can endure diverse temperatures. Remarkably, the latter two traits also render most harvested bivalves resistant to extinction.

The researchers anticipate their data will influence conservation and management decisions. Their list could spotlight species needing further extinction risk assessments.

“We want to use what we learned from this study to identify any bivalves that are being harvested that we don’t already know about,” explains Dr. Edie. “To manage bivalve populations effectively, we need to have a full picture of what species people are harvesting.”

This research is a cornerstone of the Smithsonian’s Ocean Science Center, striving to share oceanic insights with scientists, policymakers, and the public. It also aligns with the Smithsonian’s Life on a Sustainable Planet initiative, a robust endeavor addressing environmental conservation and climate change solutions.

The study is published in the journal Nature Communications.

South West News Service writer James Gamble contributed to this report.

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