Geoducks: Age before beauty

Geoduck, 2012 by Preston Singletary
Photo by Russell Johnson, courtesy of the artist

Gaaw Xaad Kil: Stan
Hlgaagilda Xaayda Kil: Stan
English: Geoduck
Latin: Panopea generosa

Forty feet below the low tideline, a field of siphons tosses millions of eggs into the blurry summer waters of Haida Gwaii. The large, spawning stan, buried deep below the sand, are visible only by the small openings at the end of their long, protruding siphons. From the end of each siphon, a single female can disperse 1-2 million eggs, drawing lightly on her lifetime supply of 5 billion eggs. As the eggs collide with sperm in the drifting haze, millions of new larval stan begin life and drift away on the tide using ‘byssal’ threads that catch the current like parachutes catch the wind.

After developing in open water for 45 to 50 days the larval stan settle in areas of the ocean with a muddy bottom, from 10 to 80 feet below the low-tide mark, though stan have been found as deep as 360 feet. There the juveniles dig themselves into the bottom with a specialized foot and start 100 years of siphoning.

Stan also use their siphons to suck plankton from the water and depending on how nutritious the water is can grow to adult size in 2-5 years; after ten years of rapid development, their growth rate slows significantly. In particular, their shell length grows much more slowly, while shell thickness increases and body weight reaches an average of one kg, with the largest animals weighing over four and one-half kg. Adult stan are distinguished by their enormous siphons, which can stretch to one metre, extending well outside their 20 centimetre shells. This makes stan the largest burrowing clam.

It is not unusual for a stan to live for over 100 years, and the oldest ever found in Gwaii Haanas – in Taa Suu Tasu Sound – was 168 years old. Anyone can tell how old a stan is by counting the rings of its shell. While the mortality rate is high among juveniles, great age amongst adults may result from low predation, although sea otters, dogfish, and starfish have proved their mettle in tackling this deep-rooted creature.

The English word for stan is ‘geoduck’, derived from its Lushootseed name, ‘gʷídəq’, meaning ‘dig deep’. Anyone who has tried to catch the fast-digging clam will agree it is aptly named.