Fauna
Invertebrate · GBIF taxon 2287849

Butter Clam

Saxidomus gigantea

Also known as Washington Clam, Smooth Washington Clam, Money Shell

Heavy, thick-shelled bivalves anchor themselves up to 30 centimeters deep in gravelly intertidal mud along North America's Pacific coastline. Filter feeding through long paired siphons, they extract microscopic algae while anchoring firmly against strong ocean currents. Indigenous coastal communities have relied on these abundant mollusks for thousands of years, leaving vast shell middens that record centuries of marine stewardship.

MarineBivalveIntertidal
Butter Clam reference1 / 7
Licensed reference(c) rlacroix, some rights reserved (CC BY) · cc-by
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Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Key facts
Diet & prey
  • Phytoplankton
  • Microscopic Algae
  • Organic Detritus
Predators
  • Sea Otters
  • Dungeness Crabs
  • Sunflower Sea Stars
ThreatsOcean acidification, habitat degradation, coastal pollution
HabitatsIntertidal and subtidal beaches with sand, gravel, and mud
Life span20–20+ years
Classification
  1. FamilyVeneridae
  2. SpeciesSaxidomus gigantea
Range & activity
Range data is not available yet.
Safe observation
Interaction riskHigh
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is high
Can store lethal saxitoxins from algal blooms; check local biotoxin advisories before harvesting.
Why it is dangerous
Accumulates potent saxitoxins during harmful algal blooms, causing Paralytic Shellfish Poisoning which attacks human nerve function.
How to recognize a risky encounter
Recognized by a thick, heavy, oval shell up to 15 cm long with prominent concentric ridges and no radial lines.
What to do
Always consult local public health harvesting closures, and avoid collecting wild shellfish during red tide events.
Responsible observation
  • Harvesting Safety: Always verify local marine biotoxin hotlines and beach closure status before collecting.
  • Spotting Siphons: Look for double keyhole-shaped depressions in wet sand near the low-tide margin.
  • Ecological Care: Refill any holes dug in mudflats to protect soft-bodied intertidal creatures from exposure.
Related species
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