Facebook-f Instagram Youtube Tripadvisor Tiktok
Search
Close this search box.

Gaper Clam

Tresus capax

Gaper Clam

Tresus capax
Other Common Names
Horse clam; the fat gaper; the Alaskan gaper
At the Aquarium
Sandy Coast
Other Common Names
Horse clam; the fat gaper; the Alaskan gaper

At the Aquarium

Sandy Coast

Appearance

Gaper clams have an oval-shaped shell that is a chalky white color. There is a wide gap at one end of the shell, for the siphons. Their 2 siphons are fused together and have a hard tip, with an inner ring of tentacles.

Habitat

Inhabit sand or muddy sand between 1 and 3 feet below the surface

Diet

Filter-feed on plankton

Life History

In Oregon, gaper clams broadcast spawn between January and April. The planktonic larval stages last between 24 and 34 days and then metamorphosis occurs, followed by the juvenile settling to the substrate.
Gaper clams can live up to 16 years and reach a maximum length of 10 inches

IUCN Status

Ecosystem & Cultural Importance

At least three different species of pea crabs will live in the tissues of a gaper clam, entering through their large and open siphons.
Native peoples harvested gaper clams. Gaper clams support both recreationally and commercial harvests today.
Range
Alaska to California
On the Oregon Coast
You can encounter gaper clams when clamming (permit required) in Oregon bays during low tide. If you do dig up a gaper clam but don’t want to keep it, be sure to place it back into its hole, siphon up. If you leave a gaper clam on the surface, they will die because they are unable to rebury themselves.
Fun Facts
A gaper clam’s age can be determined by growth rings, called annuli, on its shell. Near the hinge of the shell is a cavity called the chondrophore, and by counting the number of rings, you will know the clam’s age.

Citations & Other Resources

Back to All Animals

Contact Us

Facebook-f Instagram Twitter Youtube Tiktok Tripadvisor

Subscribe to E-Newsletter

Subscribe Now

About Oregon Coast Aquarium

Since opening in 1992, the Oregon Coast Aquarium has been a premier attraction on Oregon’s central coast and an enduring advocate for the health of our ocean. For over three decades this 501(c)3 non-profit organization has supported marine wildlife and fostered environmental stewardship through its education programs, community partnerships, and rehabilitation efforts. Accredited by the Association of Zoos & Aquariums, the Oregon Coast Aquarium is consistently ranked as one of the top 10 aquariums in the U.S., providing visitors with opportunities to connect with 15,000 animals spanning 300 different species. The Oregon Coast Aquarium is located at 2820 S.E. Ferry Slip Rd., Newport, OR. Learn more about the Oregon Coast Aquarium and its vital work at aquarium.org, 541-867-3474. Follow us on Facebook or Twitter for the latest updates.

Terms of Use

Privacy Policy

Media Policy

Copyright © 2022 Oregon Coast Aquarium. All rights reserved.

Need to update your cookie permissions?

×
Cookies
We use cookies to improve your experience and see how our guests are navigating the website. If this is alright by you, hit 'Accept All', or 'Settings' to customize and learn more. Read our cookie policy
Settings Accept All
Cookies
Choose what kind of cookies to accept. Your choice will be saved for one year. Read our cookie policy
Save Accept All