Our coast’s many fanatical razor clam diggers feel whipsawed between news that local sands swarm with delicious bivalves but that a new blob of warm seawater might produce a toxic bloom and make these clams inedible.
At this point, such worries are premature. The most recent monitoring found no upsurge in concentrations of the type of diatom that sometimes produces toxin.
Even those who wouldn’t be caught dead splashing in the surf in rubber boots plunging shovels and clam guns into the dimpled sands have to care about this issue. Recreational clamming pumps millions into the coastal economy during fall, winter and early spring months when businesses desperately need the cash infusion. Clams also form a key part of our ecological food web, sustaining Dungeness crab and other valuable species.
In the early 1990s, clam seasons have been rocked by the emergence of domoic acid. Produced by marine microorganisms that sometimes generate this toxin when exposed to warmer water, domoic acid can cause illnesses and death in mammals and birds, while apparently doing no harm to the clams that ingest it in the process of filter feeding.
There was an especially bad local domoic outbreak in 2015, toward the end of the previous development of a blob of warm seawater that started in late 2013. The 2014-15 season was ended slightly early because of domoic concentrations in clams, and aftereffects lingered through the first half of the 2015-16 season. After the toxin cleared from clams, Washington agencies packed as much harvest as they could into the remainder of that season. A similar strategy jammed as many digging days as possible into the 2016-17 season despite the longest domoic-related closure since 2002. The toxin also impacted commercial crabbing off and on in these years.
The 2017-18 and 2018-19 seasons didn’t include domoic outbreaks, but the previous enormous clam population had dissipated — possibly having died of old age. While many tiny clams were found during the summer 2018 population study, there were few sizable adults, and only four digging days were permitted last season.
Now, a harvest quota of 5.2 million — the most in modern history — has been announced for 2019-20. And almost simultaneously, there’s news a big patch of warm seawater has formed offshore — the “Return of the Blob” that Washington State Climatologist Nick Bond predicted three years ago at a Long Beach science conference. Local people have known for several weeks that nearby waters were becoming unusually warm, based on the kinds of marine life being observed and caught by fishermen.
Clam fans anticipate feeling like Charlie Brown does when Lucy snatches away the football just as he’s about to kick it.
Several points to bear in mind:
• When the previous blob formed offshore in the fall of 2013, it took a couple years before domoic acid began to be generated and reached hazardous levels in clams. So we could be OK for the whole 2019-20 season. In addition, this year’s blob is shallow and could be dissipated by the seasonal storms that have already been arriving.
• Connections between warm ocean water and the on-switch for domoic production still are poorly understood. So we may luck out altogether — or we might get clobbered sooner rather than later.
• State and federal agencies have for years set the “action threshold” for domoic acid at 20 parts per million in clams, but it’s entirely possible this may be lowered. There is a suspicion among scientists that long-term exposure to even lower toxin levels can result in harm.
• These huge pools of unusually warm seawater are popping up here and there around the world. In the South Atlantic off Uruguay, a blob similar to ours has decimated the surf clam industry. This may be a sign of things to come. “When temperatures rise 1.5 to 2 degrees Celsius (2.7 to 3.6 degrees Fahrenheit) for the globe, according to a recent report by the United Nations Intergovernmental Panel on Climate Change, one of the most severely affected ocean animals will be bivalve species — clams, oysters, mussels and their relatives. Above 1.8 degrees Celsius (3.2 degrees Fahrenheit) or so, they face “very high risks” of population decline if not extinction, the report said,” the Washington Post reported on Sept. 11. Large areas of our planet are already reaching — and even surpassing — these temperatures.
• Effective monitoring of actual ocean conditions before toxins enter the near-shore food web is vital. In addition, the states must strive for more timely information about clam conditions, and more closely tailor digging times and places to take advantage of clean clams. A new testing system under development promises to deliver toxin results within an hour of sampling, in contrast to as much as a couple days now.
• During previous domoic outbreaks, digging would have been more-often permissible if authorities had been willing to open miles-long segments of beach where domoic levels were low. State agencies believe this would be difficult to manage, as personnel could have a difficult time regulating digging in closed areas when some people walk to the beach through the dunes and wouldn’t see closure signs. These potential issues seem relatively easy to address.
• With an historically large harvest quota subject to potential spoilage if there is a toxin surge, WDFW’s decision to begin the local season early is very welcome. The agency should maximize harvest opportunities throughout the coming fall and winter. While some quota obviously must be preserved for spring and the April 11, 2020 Long Beach Razor Clam Festival, we should dig like crazy while we can. The 36 days of digging between now and the end of 2019 is a good start.
Ultimately, it may perhaps be possible to bio-engineer the offending algae so it does not produce domoic acid, or to develop other novel solutions to the problem. Without smart thinking, the warming ocean threatens not only shellfish, but an economy and lifestyle built around them.
Economic and environmental harm from marine toxins argues for investment in good science and aggressive follow through.