Annual razor clamming conservation closure on Clatsop beaches ASTORIA, Ore – The annual summer conservation closure for razor clams begins Thursday, July 15 through Sept. 30 on Clatsop beaches (from Tillamook Head in Seaside to the mouth of the Columbia River.) The annual conservation closure allows newly set young clams to establish themselves on the 18 miles of Clatsop beaches. Protecting the clams on these beaches is vital to their population and future clamming opportunities as more than 90 percent of the total razor clam harvest in Oregon occurs here. The annual closure was established in1967. When razor clamming reopened Oct. 1 last year, a good harvest season was expected as stock assessments showed high abundance with many clams over four inches. However, due to very high levels of domoic acid, razor clamming on Clatsop beaches closed Oct. 30 and remain closed due to continued toxin levels above the closure threshold.