Some of the summer's most extreme low tides are happening this week, which will provide the best chances to harvest clams and oysters.

"Shellfish populations are healthy and abundant, plus we've had some season harvest extensions on beaches," said Camille Speck, a state Fish and Wildlife biologist in Brinnon. "Hood Canal is a very robust shellfish area.

"I would encourage people to go now, especially if they plan on harvesting geoducks, since there aren't going to be many good low tides after (this month). You'll still be able to harvest steamer clams during some of the low tides in August."

The majority of geoduck populations are hunkered down well below the intertidal area, and are best usually on a minus-2-foot or lower tide. Many of the prime geoduck beaches in Hood Canal can only be accessed by boat; they can be found at http://wdfw.wa.gov/fishing/shellfish/geoduck/.

Dosewallips State Park had an extension on its shellfish-gathering season, and is open until Oct. 31. It has clams and oysters, but it takes a little walk to get out onto the beaches.

"Fort Flagler State Park had a one-month extension (open through Sept. 30), and is excellent for native littleneck and butter clams," Speck said. "Twanoh State Park doesn't open until Aug. 1 (through Sept. 30), but it is a good manila clam beach and has good oyster beds (open year-round)."

Belfair State Park is often overlooked, and is open year-round for clams and oysters, but be cautious of the muddy beach.

North Bay in Case Inlet across from Allyn is an easy, short walk, and abundant with steamer clams.

"North Bay is one of our strongest sites for harvesting, and open year-round," Speck said. "The caveat is the extremely limited parking for vehicles, and there is no parking allowed on the shoulder of the road."

The public tidelands at North Beach extend more than 1,000 feet to the south, and the farther the walk, the easier it becomes to harvest shellfish. Clams can also be found high on the beach line.

"North Bay has a replanted oyster bed, and while it does get picked over, people may still have good luck," Speck said.

One location that doesn't get much traffic is the Quilcene Bay Tideland, open for clams and oysters through Dec. 31. The steamer clam numbers at Quilcene Bay are quite good, and it's ideal for those looking to get smaller-sized clams as the minimum size is 1 ¼ inches (1 ½ inches is the standard on all other beaches).

"West Penn Cove is open again after being closed recently from the sinking (of a derelict crab boat)," Speck said. "It is a good mussel beach, and we plant oysters there too. The two open-access areas for vehicles are off State Route 20, or turn onto Madrona Way where we plant the oysters right out in front. Birch Bay (north of Bellingham) is closed for paralytic shellfish poisoning."

But before hitting the beach, be sure to do some research.

There is a year-round shellfish ban on all beaches on the east side of Puget Sound, from Everett south to Olympia, due to pollution and marine toxins, and waste-treatment plant closures.

Shellfish gatherers also need to be aware that harmful algae blooms, commonly called red tide, can pop up on beaches at a moment's notice. Toxic blooms in shellfish can cause illness or even death.

Before heading to a beach, call the marine biotoxin hotline at 800-562-5632 or visit the website at www.doh.wa.gov. Also, check the state fisheries hotline at 866-880-5431 and website at http://wdfw.wa.gov.