Statewide Harvest Rules
Puget Sound Clam and Oyster FAQ
Frequently asked questions about clam and oyster regulations and management
Shellfish Harvester Please Fill in Your Holes
Find out why this protects both shellfish and people
 

How to Dig Geoduck Clams

Like climbing Mount Rainier, digging a geoduck is often considered a rite of passage for Washingtonians - and many people will tell you it's nearly as difficult. But with the proper equipment, practice, and a willingness to get thoroughly wet and dirty, just about anyone can bring home this iconic and tasty "king clam."

Geoducks are clams, so recreational digging on public beaches is permitted only when the clam season on a particular public beach is open. Clam seasons vary from beach to beach, and from year to year, so check this website to find the current rules. Geoducks may be taken with a hand-operated instrument only. It is unlawful to thrust any instrument through the "neck" (siphon) of a geoduck, and it is unlawful to possess only the siphon of a geoduck.The daily limit, unchanged for over fifty years, is three geoducks per person. These must be the first three you dig, since adult geoducks will not survive replanting.

You'll also need a tide chart, available at sporting goods stores and in many phone books, to find the days and times of low tides. Most geoducks are exposed only during low tides of -2.0 feet or below. Such tides generally occur during daylight hours only from mid-April to mid-August.

You'll generally need to excavate a hole up to three feet deep to unearth a geoduck. Many people use a big metal or plastic tube to prevent the sides of the hole from collapsing while digging. The tube needs to be wide enough so that you can reach in with a shovel and move the sand and mud out. Some harvesters buy a galvanized garbage can and cut out the bottom, although the angled sides occasionally make it difficult to remove the can from the hole. Other harvesters use a three-foot length of commercial heating/air-conditioning duct (18-inch width). Still others weld a sheet of aircraft aluminum into a tube , or make a tube with PVC.

Using a PVC tube for geoduck
Using a PVC tube for geoduck
click on photo to enlarge
Dirty digging for geoduck

To avoid being cut by the sharp edges in all these homemade tubes, you should cover the top rim with a protective layer of flexible tubing or duct tape. Stainless steel and plastic tubes made especially for geoduck digging are also commercially available. The only other equipment you really need is a good shovel and gloves. Some harvesters prefer a posthole digger to a shovel. And don't wear your good clothes; you're going to get plenty dirty digging for geoducks.

Identification

Geoducks accessible to sport harvest are generally found in sandy or muddy ground and live at depths anywhere from 18 inches to four feet below the surface of the beach. Identification is made by the appearance or feel of the siphons, which are covered with smooth, leathery skin and do not have horny plates attached to the tip. Barnacles and seaweed rarely attach to the tip of geoduck siphons. The two halves of the siphon are joined along their full length, rather than being split. The entire siphon tip has an oblong shape when viewed from the top, and usually measures about two inches across when the siphon is open. Neither of the siphon openings has an inner row of tentacles or "fringe," and the siphon walls are thick. The exterior of the siphon is usually a creamy brown. When the siphon is partially withdrawn, an oblong "dimple" often remains in the substrate, sometimes surrounded by small pellets (pseudofeces).

Geoduck siphon - Photo by Don Rothaus Geoduck siphon
Geoduck siphon

You are more likely, however, to find siphons that are partially or fully withdrawn, as shown below.

Geoduck siphon partially withdrawn

Geoduck siphon partially withdrawn

Geoduck siphon partially withdrawn

Geoducks are most often confused with two other clam species: piddocks (Zirphaea spp.) and horse clams (Tresus spp.). Piddocks are boring clams that live only in clay, shale, hardpan or wood (although sometimes these substrates are covered by a thin layer of sand or mud). Geoducks cannot bore into these hard substrates, and therefore are never found in clay or hardpan. A piddock siphon has a split tip that is usually obvious when the siphon is open, and very thin siphon walls. Unlike the geoduck siphon, which has a leathery feel, the piddock siphon feels slippery and slimy. The exterior of the piddock siphon also has a pattern of tiny white bumps and ridges set against a dark brown background.

Horse clam siphons are frequently mistaken for geoduck siphons, although when they are open it's easy to tell the difference: horse clam siphons have an inner ring of tentacles near the tip (as seen in the photo below), geoduck siphons have no tentacles.

Horse clam siphons usually have hard, horny plates attached to the tip, and these can often be felt with fingertips. Horse clam siphons sometimes have attached barnacles or seaweed, but not always. When the horse clam siphon is withdrawn, the "dimple" or hole tends to be more circular, whereas the geoduck leaves an oblong dimple.

Piddocks - Photo by Don Rothaus
Piddocks
Horse siphon - Photo by Don Rothaus
Horse siphon
Horse siphon show
Horse siphon show

click on photo to enlargeWhat to look fSome harvesters wait until the tide is out to look for siphon "shows" or "dimples." Others like to wade in about six to eight inches of water as the tide recedes. This technique often makes it easier to spot siphons that are fully extended and pumping, but it only works if visibility in the water is good. When the water is stirred up by wave action and wind, you'll need to wait until the tide recedes to look for siphon shows. Many people like to flag siphon shows with a small marker, so that they can come back later, even after the siphon retracts, to dig the geoducks.

Once you've located a geoduck siphon, you can begin digging. As soon as it is disturbed, the geoduck will retract its siphon downward, but the geoduck itself cannot move, so you can take your time digging. If you've got a can or tube, center it on the siphon show, and force it down around the siphon as far as you can. Some diggers like to place a length of 2x4 across the top of the can, standing on it to force the can into the substrate.

Then carefully dig out the sand and mud, without slicing the siphon. As the hole is excavated, it's usually possible to force the can further down.

Once the siphon is fully exposed, continue digging using only your hands, a trowel, or a small coffee can until you can feel the shell itself. Don't be surprised if you are head and shoulders into the hole by this time. Gently wiggle the shell free; don't pull on the siphon since it will break. If you do break off the siphon, be sure to finish digging the clam and take both the siphon and the body in the shell. It is unlawful to possess only the "neck" (siphon) of a geoduck. Geoducks may only be taken with hand-operated instruments and it is unlawful to thrust any instrument through the neck of the animal.


click on photo to enlarge

click on photo to enlarge click on photo to enlarge

Cleaning and Filling In Holes

Rinse the clams well with seawater, then keep them moist by putting them in a wet gunny sack or covering them with wet cloth. Before leaving the beach, refill the holes you've dug. Failure to fill holes is extremely damaging to many species of clams. Small seed clams are smothered and killed by high earth piles left after digging, while other clams are killed by the higher temperature of water that collects in unfilled holes. Harvesting regulations require that all holes created while digging clams must be refilled. Failure to do so may result in fines of up to $75 per hole.