Skip to main content
Unsupported Browser Detected

Internet Explorer lacks support for the features of this website. For the best experience, please use a modern browser such as Chrome, Firefox, or Edge.

Giant Clam (Hippopus spp.)

Giant Clam (Hippopus spp.)

Hippopus spp.

640x427-Clam_Hippopus_Hippopus.jpg
Also Known As
Horse's hoof clam, Bear paw clam

Protected Status

ESA Candidate
Throughout Its Range
CITES Appendix II
Throughout Its Range

Quick Facts

Weight
Up to 500 pounds
Length
Up to 4.5 feet
Lifespan
100 years
Threats
Climate change, Disease, Habitat degradation, Illegal trade and poaching, Overfishing, Sedimentation and pollution
Region
Pacific Islands
Photo of three giant clams taken from above. Clams have golden brown and reddish brown color with ripple appearance. Giant clams. © Doug Helton, WOD submission

Giant clams. © Doug Helton, WOD submission

About the Species

Giant clams are the largest living marine bivalves and typically inhabit tropical coral reefs in coastal regions throughout the Indo-Pacific Ocean. Giant clams are members of the Subfamily Tridacninae, which consists of two genera: Hippopus and Tridacna.

Currently, seven giant clam species are candidate species for listing under the Endangered Species Act. This includes two species in the genus Hippopus (H. hippopus and H. porcellanus) and five species in the genus Tridacna (T. derasa, T. gigas, T. mbalavuana (tevoroa), T. squamosa, and T. squamosina (costata).

Protected Status

ESA Candidate

  • Throughout Its Range

CITES Appendix II

  • Throughout Its Range

Scientific Classification

Kingdom Animalia
Phylum Mollusca
Class Bivalvia
Order Cardiida
Family Cardiidae
Genus Hippopus
Species

Last updated by NOAA Fisheries on 09/15/2022

Featured News

Zoomed in of a giant clam from Guam. A grant project in Guam is setting up giant clam aquaculture in two southern villages, Inalåhan and Malesso. Giant clams are a culturally important species in Guam, where they’re also regulated due to overharvesting. Credit: David Burdick
Feature Story

Guam Eyes Food-Secure Future with Giant Clam Aquaculture

Pacific Islands
A photo of several of the species at risk: Acanthurus achilles, Caranx melampygus, Tripneustes gratilla, Acanthurus triostegus, Scarus rubroviolaceus, Cephalopholis argus, Octopus cyanea, Lutjanus kasmira, Panulirus penicillatus, Triaenodon obesus, Selar crumenophthalmus, Ctenochaetus strigosus, Naso unicornis, Zebrasoma flavescens, Tridacna maxima. Fifteen of the 83 species included in the Pacific Islands vulnerability assessment. From left to right: Acanthurus achilles, Caranx melampygus, Tripneustes gratilla, Acanthurus triostegus, Scarus rubroviolaceus, Cephalopholis argus, Octopus cyanea, Lutjanus kasmira, Panulirus penicillatus, Triaenodon obesus, Selar crumenophthalmus, Ctenochaetus strigosus, Naso unicornis, Zebrasoma flavescens, Tridacna maxima. Photo credit: Bruce Mundy.
Feature Story

Examining Marine Life Vulnerability to Climate Change

Pacific Islands
View More News

Related Species

640x420-Giant-Clam.jpg

Giant Clam (Tridacna spp.)

In the Spotlight

Last updated by NOAA Fisheries on 09/15/2022

Management Overview

Currently, seven giant clam species are candidate species for listing under the Endangered Species Act. This includes two species in the genus Hippopus (H. hippopus and H. porcellanus) and five species in the genus Tridacna (T. derasa, T. gigas, T. mbalavuana (tevoroa), T. squamosa, and T. squamosina (costata).

Regulatory History

In 2016, we were petitioned to list 10 species of giant clams as endangered or threatened under the ESA.

We reviewed the petition and determined that a status review should be conducted for Hippopus hippopus and H. porcellanus. A status review is currently underway.

Key Actions and Documents

Actions & Documents

90-Day Finding on a Petition To List 10 Species of Giant Clams Under the Endangered Species Act

We, NOAA Fisheries, announce our 90-day findings on a petition to list ten species of giant clam as endangered or threatened under the U.S. Endangered Species Act (ESA). We find that the petition presents substantial scientific or commercial information…
Information Gathering
,
National
Published

More Information

Last updated by NOAA Fisheries on 09/15/2022

Science Overview

Last updated by NOAA Fisheries on 09/15/2022