In 1991, Frank Cox, a biotoxin coordinator for the Washington State Department of Health, went digging for the clams. He packed his bags and sent the mollusks to a state laboratory to check for paralytic mollusc poisoning, the only marine toxin known to appear on this part of the coast.
The lab crushed the crustaceans and mixed the tissue with solvents. Then they injected the slurry into mice, a testing technique common at the time. But the mice started to do something special. Instead of breathing or dying, common symptoms of paralytic shellfish poisoning, the mice began to scratch behind their ears. The symptom, while seemingly harmless, revealed a disturbing new toxic threat: domoic acid had arrived on the West Coast.
Domoic acid is a deadly naturally occurring neurotoxin produced by Pseudo-nitzschia, a genus of planktonic diatoms or unicellular algae. When this algae is eaten by other marine animals, such as mussels, clams, and sleeper crabs, the acid builds up in their digestive tract and internal organs. And when these tasty seafood treats are ingested by humans, domoic acid can make people sick, causing headaches, stomach cramps, nausea, and diarrhea. In more severe cases, patients may also experience seizures, coma, and even short-term memory loss, which is why the condition is sometimes referred to as amnesic shellfish poisoning. After the world’s first domoic acid poisoning in 1987, three people died.
So when state officials found out what was going on with these mice in the Washington lab, they quickly shut down the entire state coastline. Electronic signs on the highway have warned visitors of the clams, and the Washington Department of Fisheries and Wildlife has sent armed agents to patrol the beaches. “The public didn’t know what was going on,” says Vera Trainer, an oceanographer with the National Oceanic and Atmospheric Administration (NOAA) who studies harmful algal blooms in the Pacific Northwest.
She says that at the time there was tremendous suspicion and anger on the part of members of coastal communities, which include many indigenous tribes who depend on shellfish harvesting for food and income. “People said, ‘Oh, the government is just saying that because they don’t want us to have fun. They don’t want us to get what is owed to us, ”says Trainer.
Since then, toxic algal blooms that create domoic acid have continued to force the closure of state beaches. On a few occasions, once in 1998-1999 and again in 2002-2003, the beaches remained closed throughout the clam season. Now in an article this month in Climatic boundaries, Trainer and colleagues find that climate change could also affect the frequency and severity of these blooms; they write that a heat wave that lasted from 2013 to 2015 made the flowers still more common. But the article also describes a solution: a unique partnership in which scientists and members of the coastal community can help monitor and manage these now long-lasting toxic blooms.
“This may not be the perfect, wonderful answer everyone wants,” says Trainer. She acknowledges that scientists haven’t found a way to stop the blooms – and that they may never go away. But she says other kinds of progress have been made. “We just improve ourselves to learn to live with these,” she said. “Yes, we find them in more places. They are more intense. We need to control climate change. But in the meantime, we can work with the people on the coast to develop these systems that will help us always have access to healthy shellfish.
Pseudo-nitzschia are found in oceans around the world, but the area around the west coast – from northern California to Washington – is particularly suited for creating flowers. The topography of the ocean floor and the coastline creates retention areas, areas where water swirls and swirls, bringing all kinds of phytoplankton and algae, Pseudo-nitzschia, up to the surface where there are lots of nutrients and sunlight to help them grow. The trainer describes them as “little oceanic mini-pots”.