Puget Sound Clam and Oyster FAQ
Frequently asked questions about clam and oyster regulations and management


The first step in setting a season on a public beach is to estimate how many clams and oysters live there. Each year, state and tribal shellfish biologists perform clam and oyster population surveys on important public beaches. Shellfish populations vary from year to year on a beach based on many factors, including water temperature, food availability, harvest, disease, flooding and other environmental disturbances. This survey information is used to cooperatively recommend sustainable, annual clam and oyster quotas on a beach-by-beach basis. By federal law, half the quota on every public beach is available to sport harvesters (the state share) and the other half to treaty tribes (the tribal share). Biologists then recommend a season that is predicted to be long enough to harvest most of the state share of clams and oysters on a beach without exceeding it.

How are these predictions made for each beach? Besides the annual state share of clams and oysters, there are three other important factors to consider when recommending clam and oyster seasons:

  • The number of daylight clamming tides.
    Sport harvesting of clams and oysters is only practical on most beaches during the daytime, and only on tides lower than about 2 feet. On average, there are 144 such tides each year, but every year is different, and the number of clamming tides also varies from week to week. One thing that makes a big difference from year to year (and week to week) is how many minus tides fall on weekends and holidays.
  • The number of people predicted to harvest clams and oysters each daylight clamming tide.
    This varies dramatically from beach to beach. The number of people using the the beach also varies a lot depending on how high or low the tide is, and whether it's a weekend or a weekday. It also varies quite a bit from year to year. Agency biologists conduct numerous ground and aerial surveys of sport clam and oyster harvesters each year on all the important beaches, and this historical record is used to help make those predictions.
  • The average catch of clams and oysters taken by individual harvesters each day.
    This varies from beach to beach, mostly depending on the species of shellfish available. This information comes from numerous creel surveys conducted every year in which sport harvesters are interviewed as they leave the beach, and their catch is counted and weighed.


    Finally, there are often other factors to consider when recommending a season. At many beaches, for example, concerns about public health, parking facilities, user conflicts, or special events must be considered. And as much as possible, managers try to spread out the harvest opportunities within a geographic area. Ultimately, setting sport clam and oyster seasons is a cooperative effort among WDFW, State Parks, county governments, and the public. Seasons are recommended annually to the Fish and Wildlife Commission, and formal public comment is encouraged, either in person or by letter. The Fish and Wildlife Commission sets the Puget Sound clam and oyster seasons at their meeting in early February each year, and these seasons go into effect on May 1st, appearing in the Sport Fishing Rules pamphlet. These seasons are sometimes modified by emergency regulations, so be sure to check by either calling the toll-free Shellfish Rule Change hotline (1-800-880-5431) or on the Emergency Rule Change website.


GPS way-points mark sample locations on a typical public clam beach.

Each year, state and tribal shellfish biologists perform clam and oyster population surveys on the important public beaches. The goal of each survey is to estimate the total number and weight of clams and oysters on the beach, especially those that are of legally harvestable size. This information is then used to help recommend clam and oyster seasons.

Surveys are conducted in the late spring or summer after the sport clam and oyster season has ended on the particular beach, wherever possible. A team of biologists arrives at the beach several hours before low tide. They begin the survey at a random starting point on the beach close to the boundary, and then proceed to dig samples systematically at intervals along the entire beach. The goal is to obtain a truly representative sample of shellfish from the beach, with no bias toward either "good" or "bad" areas.

Clams of each species are sorted and counted from the samples, and some of these samples are bagged up and taken back to the laboratory where they are individually measured and weighed. The information gathered on the average number of clams per square foot, their average weight, and the total area surveyed provides an unbiased estimate of the number and weight of clams on the entire beach.

The lead biologist uses a hand-held GPS unit to accurately space out the sample locations and record their exact position. Each sample is marked with a flag, and biologists carefully dig a square foot sample at each flag.

These estimates are then used to recommend the annual quota for the next year's season. For example, management plans currently recommend that the annual quota for native littleneck clams on a beach be 25% of the total estimated weight of legal-sized clams (those with shells larger than 1.5 inches). For Manila clams, a non-native species introduced from Asia in the early part of the last century, the annual quota is 33% of the total estimated weight of legal-sized clams. The surveys also provide valuable information on whether or not younger clams and oysters have settled on the beach, any shifts in the species of clams living on the beach, and specific areas within the beach which may have increasing or decreasing numbers of shellfish.


Photo by Peter Haley, 2003,
courtesy of the Tacoma News Tribune
Estimates of how many clams and oysters are harvested off a beach each year help biologists manage the seasons so that the harvest remains sustainable. Federal courts also require the state to estimate the recreational catch of clams and oysters on the important public beaches of Puget Sound. Each year, biologists take to the sky to "count heads" on public beaches from agency aircraft. Supplemented with ground based counts, this information -- the number of sport harvesters on the beach -- is combined with catch rate information gathered on the beach during creel surveys. Along with the number of clamming tides, this information allows biologists to estimate the total sport catch of clams and oysters on individual public beaches.

Flight routes cover all the important public beaches and "follow the tides" throughout Puget Sound so that a head count of sport harvesters is made close to the time of local low tide on each beach. Only sport harvesters are counted. That count at low tide is then expanded to produce an estimate of the total number of sport harvesters using the beach all day (on most beaches, the total number of harvesters all day long is roughly three times the number digging on the beach exactly at low tide). Approximately 50 flights are made each season between March and September, and these provide reliable estimates of the total sport use on weekends, weekdays, and at different tide levels. (Feel free to wave as we fly over!)

Meanwhile, information on the average daily catch rate of sport harvesters is being gathered on the beaches themselves. On random days throughout the season, agency creel survey technicians interview sport harvesters leaving the beach, counting and weighing their catch. This provides accurate estimates of both the average catch per harvester, and the different species of clams coming off the beach. And if you're unsure of the finer differences between clam species, be sure to ask our technicians, they're happy to show you. They're also happy to help you understand the regulations, or even to share clamming and oystering tips.

Estimates from the aerial surveys and beach-based creel surveys are combined to estimate the season-long sport catch of clams and oysters on important public beaches throughout Puget Sound. This information helps biologists to sustain the shellfish populations, and is also vital in setting the clam and oyster seasons.


The legal minimum size for Manila clams, native littleneck clams, butter clams and cockles on public beaches is 1.5 inches. There is no minimum size for any other species of clam (this includes geoducks, horse clams, varnish clams, and softshell clams) nor is there any minimum size for mussels. At Quilcene Bay WDFW Tidelands, the legal minimum size for clams is 1.25 inches.

Minimum sizes are set for these clam species for two reasons:

To maintain a sustainable resource. These clams reach sexual maturity and have a chance to spawn at least once before they reach 1.5 inches; and,

To prevent waste of the resource. Clams grow fastest when they are small, so taking them before they reach 1.5 inches wastes all that potential for growth. Undersized clams and any clams not taken can be easily replaced in the harvest hole and covered shallowly; they'll survive just fine, grow bigger and have a chance to spawn. Click here for more information on the requirement to fill clam holes.

Why aren't there size limits for geoducks and horse clams? Because once dug, these deep-dwelling clams have a very poor chance of surviving if they are replaced in the harvest hole. Likewise, the fragile shell of eastern softshell clams makes them poor candidates for surviving. For these reasons all eastern sofshell, geoduck, and horse clams must be retained regardless of condition as part of the limit.

How can you tell if your clam is above the legal minimum size? It's easy with a light plastic clam, shrimp, and crab gauge, sold cheaply at most sporting goods stores. Just try to fit the clam through the hole; if you can turn the clam in any way so that it won't fit through the hole, that clam is above the minimum size. If it falls through no matter how you turn it, it's too small and must be returned to the hole. And notice that this same gauge is designed for measuring Dungeness crabs and shrimp to determine if they are above the legal minimum size.

By the way, you may notice very small Manila clams being sold in supermarkets. These clams are grown by private shellfish farmers on private tidelands, and they aren't governed by the legal minimum size. Most of these shellfish farmers buy or grow "seed" with which to replant their private beds.

The vast majority of oysters on public beaches are Pacific oysters which were introduced from Japan. The legal minimum size for oysters on all tidelands is 2.5 inches. The minimum size for oysters is mainly designed to protect the native Olympia oyster (Ostrea conchaphila). Olympia oysters, once common in Puget Sound, were practically wiped out by pulp mill effluent and over-harvest in the early part of the last century. Restoration efforts are underway, and small pockets of these native oysters remain on many Puget Sound public beaches. They obviously need protection, but they are not easy to identify - to many harvesters they just look like small Pacific oysters. So the easiest way to protect them is to prevent any harvest of oysters smaller than 2.5 inches (because Olympia oysters almost never reach that size). Small Olympia oysters often attach to Pacific oyster shells, so be sure to shuck all your oysters on the beach and leave the shells there. Click here to read about the requirement for oyster shucking on the beach.


A shellfish/seaweed license is required for anyone 15 years of age or older to harvest clams and oysters. Consult the current Fishing in Washington Sport Fishing Rules pamphlet or visit the Licensing web site for more information. You can also buy a fishing license on-line at this site.

Click here to find a license vendor in your area.


The Fishing in Washington Fishing Rules Pamphlet that is issued each May lists all of the seasonal clam and oyster beaches and their seasons. Web pages that provide seasons for most of these beaches can also be accessed at http://wdfw.wa.gov/fishing/shellfish/beaches. Driving directions and specific access instructions are provided for some beaches.

Seasons for beaches that open before May or that may be closed or opened by emergency regulation can be tracked on the web pages or by calling the Shellfishing Rule Change Hotline at (866) 880-5431.

Because pollution and biotoxin conditions change rapidly, harvesters are also reminded to call the Marine Biotoxin Hotline (800) 562-5632, or check the internet on the day you plan to harvest.


Through treaties with the United States, the tribes reserved their right to half of the harvestable surplus of shellfish on all public lands and private tidelands within the treaty case area of Puget Sound, except those lands which have been "staked and cultivated." These treaty rights have been reaffirmed by the United States Supreme Court.

You can get more detailed information on tribal shellfish management activities by clicking here.

Each year, the state and tribes negotiate and sign management plans which govern the harvest of clams and oysters on public tidelands. These plans stipulate the amount of clams and oysters available for harvest on all important public beaches, minimum size limits, methods of surveying beaches and reporting catch, penalties for over-harvest of the shares, and many other fishery management issues. By law, the harvestable amount of clams and oysters is shared 50:50 between the state and tribes, unless the parties decide that "trading" portions of their share on certain beaches is mutually advantageous. The scientific survey methods used by state and tribal biologists to estimate clam and oyster populations are virtually identical, and our biologists often collaborate on surveying beaches for clams and oysters. State and tribal shellfish biologists also share scientific data, catch information, and collaborate on new methods to improve management of the clam and oyster resources.


Manila clam "seed" being broadcast on an enhanced shellfish bed.

The harvestable amount of clams and oysters on all public beaches is shared equally among sport harvesters and treaty tribes. Only the method of regulating those harvests differs. The main difference between tribal harvest and "state" harvest of clams and oysters on public tidelands is that tribal harvest is primarily commercial (although treaty ceremonial and subsistence harvest also occurs). Also, the number of tribal diggers is a small fraction of the number of non-tribal sport diggers. Tribal members may harvest more days and have higher individual harvest limits because there are far fewer tribal harvesters compared to recreational diggers.

Tribal commercial clam and oyster harvests must, by agreement, be scheduled for certain days on certain beaches. Tribal monitors weigh and record the catch as it comes off the beach. When the tribal share of clams and oysters on a beach is reached for the year, the tribal fishery is closed on that beach.The state's share of clams and oysters on public tidelands, on the other hand, is reserved almost exclusively for sport harvesters. On the majority of public tidelands, the sport clam and oyster season is open year-round, seven days a week, and thousands of sport harvesters participate in the fishery. On the major public beaches (those with specific clam and oyster shares), the taking of the sport share is regulated by daily limits and by setting seasons. These daily limits and seasons are designed to provide the most recreational opportunity, over the longest period of time, for the most people. The sport catch, unlike the tribal commercial catch, cannot realistically be monitored and weighed on public beaches which are open seven days a week and visited each day by scores of sport harvesters. Instead, the sport catch of clams and oysters is estimated each year by aerial and creel surveys performed by Washington Department of Fish and Wildlife biologists.

A geoduck which grew from "seed" on an enhanced shellfish bed.

These two strategies for regulating tribal commercial and state recreational fisheries therefore achieve the same goal: The harvestable surplus of clams and oysters on public beaches is shared equally among tribal and sport harvesters.


Shellfish enhancement is a management tool used by Washington Department of Fish and Wildlife to increase opportunities for recreational harvest on certain public beaches by adding to the clam and oyster resource which occurs naturally. Our enhancement technique is to routinely "seed" suitable beaches with juvenile clam and oysters. Not all beaches need enhancement; many public beaches in Hood Canal, for example, provide plenty of sport harvest opportunity based entirely on natural clam and oyster production. And not all beaches are suitable for enhancement; wave action, strong currents, unsuitable habitat, and the presence of natural predators rule out the chances for successful enhancement on many public beaches. But on those public beaches suitable for enhancement, planted "seed" generally grows to harvestable size in two to three years.


The state presently seeds enhanced beds with Manila clams and Pacific oysters. These are the primary species currently being sold as "seed" and we have a long history of success planting them. We also planted geoduck clams until the closing of the state shellfish hatchery. When our hatchery was operating, we raised much of the shellfish seed ourselves. Since the hatchery closure, we purchase clam and oyster seed through a competitive bidding process from commercial shellfish hatcheries operating in Washington and California.

Oyster shell cultch containing "seed" oysters is washed onto a public beach.

Clams and oysters are "broadcast spawners," meaning that the eggs, sperm, and resulting larvae mingle and move about in Puget Sound's swift water currents. It is unlikely that offspring from the planted clams and oysters would settle as larvae on the same beach from which they originated. For this reason, artificial shellfish beds periodically need to be re-seeded. Shellfish enhancement on individual beaches is not intended to be self-perpetuating, but the progeny from planted shellfish likely add to the general clam and oyster population in Puget Sound.