Neither Gooey Nor a Duck

by Gail Wellenstein, Kitsap Beach Naturalist

Geoduck

Low tide walks bring out curious beach walkers happy to share their finds, or others who approach with a plastic grocery bag, offering to let me peek inside to reveal a denizen of the deep intertidal sediment. It’s the elusive geoduck, mascot of Evergreen State University and the butt of many salacious jokes.

Geoducks are the largest burrowing clam in the world and one of the longest-living animals on our planet. Their age is determined by the annual rings deposited on the shell, with an average lifespan of 140 years. The oldest was 179 years old. Geoducks are “broadcast spawners”; males and females release millions of reproductive cells into the water simultaneously. Most eggs are not fertilized, but if it happens, the tiny baby will develop a foot within 48 hours that it uses to dig into the mud.

After the first year, that clam will be at least one foot deep in the sediment and this burrow becomes its lifelong home. They grow quickly the first five years, reaching their maximum size of seven pounds at the age of fifteen. By this time, they may be three or more feet below the surface of the sediment, with the depth being limited by the length of the siphon. The shell of an adult geoduck is six to eight inches long, but the siphon adds three or more feet to their total length. This depth is their main defense against non-human predators. Sea otters are known to dig for geoducks; sea stars will nibble at the siphons, whose tips are at the surface of the sediment.

The siphon has two openings: one for taking in water filled with oxygen and plankton, its main food; and one for releasing water and debris. This filter feeding is beneficial to the environment as it removes algae and excess nutrients from the surrounding waters, improving water quality. The siphon is the edible part of this clam. It’s served sautéed in a stir-fry or eaten raw like sushi. Their meat is slightly sweeter and crunchier than most clams. It’s been a part of the northwestern Native American diet for centuries.

If you have a shellfish/seaweed license, head to beaches with lots of sediment, such as Shine Tidelands, and go at a low tide of at least negative two. The limit is the first one dug per day per license. Geoducks are farmed commercially, with 95% going to China. Because they only live on the Northwest coast of North America, they are considered a delicacy with purported aphrodisiac qualities. A healthy live geoduck can go for up to $100 per pound in Hong Kong. It’s not a surprise that the limited harvest and high prices have led to new crimes of “clam rustling” and “shellfish smuggling”. This might make an intriguing plot line for a Netflix crime series: beautiful setting, skullduggery, international travel. Any takers?