LONG BEACH — After giving south Washington coast clam diggers a pre-Halloween scare, levels of the troublesome marine toxin domoic acid receded in samples collected on Oct. 24. This allowed a seven-day opening to start Oct. 26 and run through Nov. 1.
Before the season and in followups before each individual opening, domoic levels have to be less than 20 parts per million in the meat of clams taken from several locations.
On the Long Beach Peninsula, samples are collected from up to four sites. All must be below 20 ppm before a set of clam digs is permitted anywhere on the peninsula’s 28-mile coastline.
On one occasion in recent years, domoic levels rose above safe levels during a multi-day dig, prompting state officials to urge harvesters to discard their clams.
To avoid such close calls, state agencies not only sample clams but also monitor levels in nearshore ocean waters of the marine diatom, Pseudo-nitzschia, the organism that sometimes produces domoic acid.
In the run-up to the Oct. 26-Nov. 1 opener there was a concern that Pseudo-nitzschia levels might be on an upswing.
Precautions are warranted. This toxin is capable of causing illnesses ranging from indigestion to death in mammals and birds. It is most notorious for its neurological impacts and an illness called amnesic shellfish poisoning that can permanently degrade the ability to form short-term memories.
This year from April 9 through Sept. 17 no samples collected on the peninsula exceeded 2 ppm. Samples collected Oct. 15 topped out at 5 ppm. Samples collected Oct. 20 included a result of 8 ppm from the razor clam reserve area near Surfside and a result of 6 ppm from a sampling area about midway on the peninsula. This upward trend over the course of a few days prompted the delay in formally approving the Oct. 26-Nov. 1 opener.
Samples collected on Oct. 24 found a level of 7 ppm in the northern reserve area and 6 ppm around midway. This eased concerns about a potential upward spike in levels.
The opener announcement was also delayed for the area of beach that WDFW refers to as Twin Harbors, which stretches from the mouth of Willapa Bay north to almost Westport. Testing at diverse locations there rose from a high of 1 ppm on Sept. 16, to 5 ppm on Oct. 15, to 6 ppm in the north and 4 ppm in the middle on Oct. 20. The most recent Oct. 24 tests found a maximum level of 3 ppm in the north and 6 ppm in the middle.
Remaining confirmed digging dates this week are:
• Oct. 30, Wednesday, 9:03 pm, -1.2 feet; Long Beach, Twin Harbors, Copalis
• Oct. 31, Thursday, 9:50 pm, -0.8 feet; Long Beach, Twin Harbors, Mocrocks
• Nov. 1, Friday, 10:38 pm, -0.2 feet; Long Beach, Twin Harbors, Copalis
Providing the domoic level remains low, digging will resume on Nov. 11 for seven days.