Assessing razor clam populations for conservation and recreation
Pick a spot on the beach, pump water into the sand, and count and measure the razor clams that appear. Repeat.
After a few months — and 58 miles of beach — there’s enough data on razor clam quantities and sizes to determine population health and balance recreational harvest opportunities with protecting the resource.
The Washington Department of Fish and Wildlife’s (WDFW) annual razor clam stock assessments typically run from May or June until August or September. As with the digging season, stock assessments are based on low tides.
Biologists and scientific technicians cover all five razor clam beaches: Long Beach, Twin Harbors, Copalis, Mocrocks, and Kalaloch.
Each day the tide is low enough — whether that’s morning or middle of the night — they place a half-square-meter ring on the sand and pump water from the surf at 100–120 gallons per minute. It takes about three minutes for the ring of sand to liquify, causing the clams to slowly be released from underground and float to the surface. The team counts and measures each clam before carefully placing it back in the sand.
“Simply liquefying the sand, rather than digging, allows us to reduce harm to the clams,” said Bryce Blumenthal, WDFW’s recreational razor clam manager. “We replant them, orient them the way they would appear when you dig them up, and they go back into the sand just as well as they came out.”
Digging would also take too long and require clams to create “shows,” or small holes in the sand indicating their presence. Because not all clams show at the same time, it would be impossible to count all of them this way.
Biologists and scientific technicians pump water into six rings every 50 feet from the top of the clam beds to the water’s edge. They can estimate how many are likely in that entire area based on the number of razor clams in each ring.
The starting point is selected at random, and they repeat the process about every mile of the beach.
“It’s systematic, random sampling,” Blumenthal said. “We don’t want bias in our decision-making. We don’t want to do this work in an area where there are a lot of clams and overestimate the population. In the same way, we don’t want to do this in an area where there aren’t a lot of clams and underestimate. We leave it up to chance and do enough sampling to have it even out and be representative of the population at large.”
The 2023–24 recreational razor clam digging season ended May 12, and the 2024–25 season is tentatively slated to open with an Oct. 3–7 dig series. Long Beach, Twin Harbors, Mocrocks, and Copalis are all expected to open to recreational harvest. Kalaloch has been closed since the 2019–20 season, as clams there remain small and low in numbers.
Razor clams measuring at least 3 inches are known as recruits, and those under 3 inches are called pre-recruits. Recruits represent the ideal harvest size, although people legally must keep the first 15 clams they dig, regardless of size or condition, to prevent waste.
The Department assesses and manages each beach individually. For example, because Twin Harbors saw an increase in recruits this year, more digs are scheduled there. Fewer digs are scheduled at Copalis, which saw a six-year low in recruits.
“We like to see clams of various sizes,” said Clayton Parson, a coastal shellfish technician. “It’s always encouraging to see the bigger clams, but if you’re not seeing any pre-recruits behind them, then you know in the future it might be a bit of a light year.”
Fishery managers will monitor harvest throughout the fall and spring to ensure the number of razor clam digs do not threaten sustainability. Limited non-tribal commercial razor clam harvest also occurs in the spring and early-summer in an area known as the “Willapa Spits,” sand islands near the mouth of Willapa Bay that are typically only accessible by boat.
Razor clam populations fluctuate by year and by area of the beach for various reasons, including ocean and weather conditions. This year’s stock assessments showed more small clams and fewer big clams. Overall, though, populations still look strong and healthy.
“It’ll probably be a similar situation to last year, which was good,” Blumenthal said. “There were enough razor clams to allow for ample digging all the way through the season.”
Luck may still vary, as razor clams sometimes go dormant in harsh weather or after spawning. Not collecting your daily limit of 15 clams doesn’t necessarily indicate a low population; it could just mean the clams aren’t cooperating.
When the summer stock assessments finish, WDFW and Quinault Indian Nation (QIN) discuss population estimates and set the total allowable catch for each co-managed beach.
Co-management makes the process more efficient. On Copalis, Mocrocks, and Kalaloch, QIN biologists and technicians conduct stock assessments on half of the beach while WDFW staff work on the other half. They use the same water pumping method and share data for joint population estimates.
The Hoh Tribe also provides staff to help move gear for assessments at Kalaloch, where there is no vehicle access on the beach.
“It’s a well-oiled machine,” Parson said. “Before working with the tribes, we sampled the whole coast on our own. We would start in spring and typically go until September, and it was challenging.”
All scheduled dates for the 2024–25 recreational razor clam season remain tentative. The Washington State Department of Health requires testing of razor clam samples for marine toxins, and final approval usually occurs a few days to a week before the start of each dig series.
Domoic acid levels must fall under the guideline level before a beach can open for harvest. This natural toxin, produced by certain types of marine algae, can be harmful or fatal if consumed in sufficient quantities.
Visit WDFW’s razor clam webpage for more information on management of this fishery. At the bottom of the page is the 2024–25 Razor Clam Management Plan, which includes population estimates, average clam sizes, and average density (clams per square meter) for all five management beaches.
The Washington Department of Fish and Wildlife works to preserve, protect and perpetuate fish, wildlife and ecosystems while providing sustainable fish and wildlife recreational and commercial opportunities.
