I live in Kitsap county, WA, where the surrounding waters of Puget Sound have the largest and densist population of Geoduck in the world. If you have eaten them in an asian resturant, they were most likely harvested here. I occassionally dig them on those rare occassions when we have -3', or lower, tides. The "citizen" limit is three, and collection is limited to only a few tides a year that are low enough. Scuba divers take a few, as well. For the most part, they are not dug by citizen harvesters through most of their habitat because the tides simply don't go that low. The body is located feet bellow the surface, and it takes skill (and special equipment for the deepest clams) to dig the whole clam without damage. In the past, it was common just to dig deep enough to get ahold of the neck, and rip that off, leaving the body which has more and better meat behind to die. That is now illegal. In my experience in 5 years of digging them, I've never seen anyone rip a neck. And if I did, I'd make sure fish and game knew who did it.
Commercial harvest is done by air supplied divers with water vacuum pumps. A hole 3 or more feet deep is sucked out for each and every clam dug. Since harvest is limited by number, commercials routinely "high-grade", or leave smaller clams on the bottom. High-graded clams cannot re-dig themselves, and always die. Commercial harvest happens below the mean low tide mark so the bottom damage and remains of high-graded clams are invisible to the people who live here.
As bad as commercial harvest of Geoduck is, it is about to become worse. Washington Department of Natural Resources (DNR) has expanded the Geoduck dig allowed off of our shores for commercials. WA DNR has a truelly abysmal record of manageing commercial harvest, with several fish specie that were common just a few years ago now collapsed, and some even endangered. Geoduck follows the same pattern: develop a resource as marketable, then exploit it until it collapses. Dungenous crab and littleneck clams are about the only marine resource that the DNR has successfully managed in Puget Sound, and that is only because these replace themselves fairly quickly.
Geoduck don't replace themselves quickly. A marketable-sized geoduck takes decades to grow. The largest ones are older than anyone reading this. So you can begin to understand my chagrin when I read about my local clam showing up as a curious delicacy in Asia. IMO it will last a short while, the clam population will collapse, and the clams won't recover their distribution and average size within my lifetime or your children's lifetime, if ever.
Please don't help create a commercial market for these. Get the littlenecks. They are cheaper, the harvest is viable, and they taste better. Sustainable harvest for Geoduck is, IMO, just a tiny fraction of the existing population. That is how it has been for these clams for centuries. It is infuriating for me to see our local marine resources pillaged beyond sustainable levels repeatedly, and I fully expect Geoduck to be Puget Sound's next specie to go from locally common to rare or endangered.
Why do you people collect marine animals to put in tanks? Don't you value them? Or are they just curios to impress your friends until they die from your lack of knowledge of their habitat or physiology? Do you have any clue how bad it is for some marine animals, both in the food market and the pet market alike? I am not an environmentalist and this is not a rant. I'm a conservative who believes that it serves everyones best interest to harvest wild resources in a sustainable manner. "Supply and demand", when applied to wild specie that may never recover its distribution if severely denuded, means that there may never be a "supply" again.