The geoduck (pronounced “gooey duck”) is a large clam native to the west coast of North America. Unlike the giant clam, which is almost all shell, the geoduck has a small shell compared to the soft part of its body, which it cannot retract into the shell. The shell rarely grows larger than about 8 inches (20 cm), but the soft body can be over 3.3 feet (~1 m) long. Geoducks burrow deep into soft, muddy or sandy sediments, and this long “neck” is actually the siphon that the clam uses to bring clean seawater down to the deeply buried shell. They are the largest of all burrowing clams.
Geoducks are filter feeders. The water that they siphon down to the buried main body is filtered for small particles of food, phytoplankton, pelagic crustaceans, and fish larvae. This water is also the source of the animal’s oxygen and is actively pumped over the gills.
This species reproduces through a behavior known as broadcast spawning, where several females release eggs and several males release sperm into the water column, all at the same time. This method increases the likelihood that eggs will become successfully fertilized and that fertilized eggs will not be eaten by egg predators near the seafloor. Geoducks are extremely productive, with the long-lived females producing as many as five billion eggs throughout their lifetimes. Very few of these eggs will survive all the way to sexual maturity. Geoducks have a very long lifespan, with individuals known to reach ages over 165 years old.
Geoducks are a highly valuable seafood species, with individuals demanding as much as US$150 per pound ($US330/kg). As a result, this species is fished commercially and farmed professionally throughout its range. Both of these industries are apparently sustainably managed, and this clam is still common. Conservation scientists have not assessed the geoduck, but it is likely a species of least concern.
Oceana joined forces with Sailors for the Sea, an ocean conservation organization dedicated to educating and engaging the world’s boating community. Sailors for the Sea developed the KELP (Kids Environmental Lesson Plans) program to create the next generation of ocean stewards. Click here or below to download hands-on marine science activities for kids.