WASHINGTON— Responding to a petition by biologist Dwayne Meadows, Ph.D., and following the Center for Biological Diversity’s notice of intent to sue, the National Marine Fisheries Service proposed today to protect 10 giant clam species under the Endangered Species Act.
“These iconic giant clams play a crucial role in the ocean ecosystem and reef habitats, and I’m thrilled they may get the protection they need to survive and flourish,” said Dwayne Meadows, Ph.D. “Giant clams are being exploited purely as a luxury and curiosity, and we’ve got to do everything we can to stop people from harvesting them. These species are also suffering from the climate warming and bleaching effects that are decimating corals. Protection under the Endangered Species Act is an important step toward helping the species rebound.”
Giant clams — the largest grow to a shell length of 54 inches and weigh nearly 500 pounds — live in coastal areas next to coral reefs in the Red Sea and the Indo-Pacific. Giant clams are generally fast-growing and mature between two and nine years of age, depending on the species. The oldest known reliably aged giant clam was 63 years old.
“Preventing U.S. imports of giant clams under the Endangered Species Act is so critical to helping these species avoid overexploitation and fight the climate-related challenges they already face,” said Lauren Parker, an attorney at the Center for Biological Diversity. “Climate change is wreaking havoc on giant clams’ ocean habitat, acidifying waters and creating devastating marine heat waves. I’m so glad the United States is joining the international community in standing up for these beautiful creatures.”
Five giant clam species are proposed for endangered listings — porcelain or China clam, smooth giant clam, true giant clam, devil or tevoro clam, and Red Sea giant clam. Of the five species proposed to be protected as threatened, the horse’s hoof clam was listed based on the threats it faces, while the remaining four were listed because they look similar to the other listed species.
Three of the giant clams proposed for protection occur in the United States — horse’s hoof, smooth giant clam and true giant clam — but the Fisheries Service has not identified any critical habitat areas.
Subsistence and commercial harvest for meat consumption and shell trade are threatening giant clams. The giant clams in the Red Sea have declined to less than 5% of their historical abundance in the 1980s and 1990s. Throughout the Indo-Pacific region the clams have suffered similar rates of decline and completely disappeared in a few locations.
Most countries have laws that prohibit commercial exploitation of giant clams, but the international shell trade continues and subsistence harvest is ongoing in many places. One exception is Australia, where laws prohibiting early harvest and strict enforcement have been largely successful.
Giant clams’ interdependence with coral reefs means they are likely vulnerable in similar ways to climate change and water pollution. The continued loss of coral reefs could decrease the ability of young giant clams to find suitable hard-surface habitat on which to grow. Giant clams are also likely harmed by ocean warming like coral reefs, suffering a similar bleaching response.
The proposed designations follow a 2016 petition submitted by biologist Dwayne Meadows and the Center’s December 2023 notice of intent to sue the Fisheries Service for failing to make a listing decision. The Fisheries Service announced in June 2017 that protections may be warranted.
Listings under the Act will protect these clams from overexploitation due to international trade while helping to raise awareness about these species and their need for protections.
