Marine Toxin Levels Dropping, But Not Enough for Razor Clam Digs


State shellfish managers were hoping for some good news this week from domoic acid tests on razor clams. They didn't get it.

"We were hoping that today's razor clam domoic acid results would allow us to open Mocrocks," said Fish and Wildlife Coastal Shellfish Manager Dan Ayres Tuesday.

Instead, results showed levels above the maximum allowable parts per million of domoic acid in clam meat — 20 — taken in test digs at Mocrocks. To open any beach to digging, domoic acid levels in razor clams must be below 20 parts per million in two sets of consecutive tests done at least seven days apart.

In the recent test, levels were just 1 part per million on the south end of Mocrocks, but were between 20 and 27 in parts of the beach north of there.

"Reopening this fishery after a long domoic acid cloture has always been frustrating. (We) continue to follow the historical pattern of slowly depurating (losing) domoic acid and for the last several months we have observed the levels bounce around considerably," said Ayres, who added the recent round of tests "shows some nice declines on all beaches" over the past few weeks.

Tests over the last year showed domoic acid levels OK for consumption until late October, when digs were canceled. At Mocrocks, the levels have dropped over the past several weeks, down to well below dangerous levels, but the latest test dig showed levels up to 20 and over.

Fish and Wildlife has a site dedicated to showing trends in domoic acid levels, There, broken down by beach, you can see the results of the previous year's tests, and also click on the "Show historical data" to see the numbers from previous years. Since October, the graphs for each beach show clearly the "bounce around" in levels referred to by Ayres.