A large cooking pot filled with clams and stock
Image credit: Makafood

Shellfish lovers around the world are harvesting more than 800 varieties of clams, oysters, mussels and other seafoods, expanding the range of recognised species exploited by humans and highlighting where sustainable harvesting needs to be considered to avoid overexploitation.

In new research published in Nature Communications, an international team of biologists and ecologists have extensively increased the numbers of shallow-marine bivalves known to be exploited by humans for food, adding 720 species to the 81 reported in the United Nations FAO Production Database.

As well as identifying the global ‘hotspots’ where exploited bivalves are, the team led by researchers from the University of Birmingham and the Smithsonian Institution in the U.S. have identified certain areas where there are higher vulnerabilities to overexploitation, and include a list of species at greatest vulnerability.

Among the top ten at-risk species are oysters found off the coasts of Malaysia, and the Philippines, paper scallops from the Gulf of Mexico, and venus clams found off the Atlantic coast of Central Africa.

....responsible fishing can diversify the species that are gathered and avoid making oysters the dodos of the sea.

Dr Shan Huang

Dr Shan Huang, Assistant Professor of Paleobiology at the University of Birmingham and corresponding author of the paper said:

“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. The human effect therefore can disproportionately remove the strong species.

“By identifying these species and getting them recognised around the world, responsible fishing can diversify the species that are gathered and avoid making oysters the dodos of the sea.”

Clam farm construction in sea
Image credit: Quang Nguyen Vinh

Dr Stewart Edie, Research Geologist and Curator of Fossil Bivalvia at the Smithsonian Institution and joint first author of the paper said:

"Humans have wiped out populations of bivalves in the blink of an eye, geologically speaking, and so this is a bit of a wake-up call to check on how resilient clams and mussels are to both natural and human-caused environmental changes."

Dr Katie Collins, Curator of Benthic Molluscs at the Natural History Museum in London, and a co-author of the paper said:

“While it's good news that many of our favourite bivalves to eat have a low baseline extinction vulnerability, it's crucial that we manage them, and the climate, carefully to ensure we can continue to have these bivalves around for the future.”