AP Photo/Eric Risberg

There have been a lot of stories about the giant toxic algae bloom off the West Coast this year. It has harmed marine life, stymied recreational activities and shuttered commercial fishing enterprises.

Now the algae, a particular single-celled plant called Pseudo-nitzschia that is a food source for small fish and shellfish, is claiming its latest victim: Dungeness and Rock crabs. With the start of the Dungeness crab fishing season just around the corner on November 15, the timing couldn't be worse.

On Tuesday, the California Department of Health warned people to avoid eating Dungeness and Rock crabs due to the detection of dangerous levels of domoic acid, a naturally occurring toxin. According to the officials, the levels of domoic acid in crabs' body meat as well as the internal organs, i.e. crab butter, could pose a serious health risk if consumed.

The symptoms of consuming domoic acid range from headaches, vomiting and dizziness in mild cases of consumption to confusion, disorientation, and even coma or death in severe cases, according to the CDHP. As of Tuesday, there had been no reported cases associated with the toxicity levels. The warning is in effect for crabs caught in waters between the Oregon border and the southern Santa Barbara County line.

While any health scares are yet to be felt, the potential economic impact is rippling across the industry. Jordan Traverso, a spokeswoman at the California Department of Fish and Wildlife, told the Associated Press that California's commercial crabbing industry is estimated to bring in at least $60 million a year.


Geoff Shester, the California program director for Oceana, an ocean conservation group, told Fusion that Dungeness crab, along with market squid, are the two most valuable fisheries in the entire state.

He said that while many ocean researchers are hoping the algae bloom subsides and that this isn't a new normal, "it's a huge warning sign of what can happen when there are changing ocean conditions and climate change impacts."


"This is very consistent with the type of things that start going haywire when we have a warmer ocean," he said.

Shester said the domoic acid from the algae works its way up the food chain, amplifying in concentration as it goes. It starts with the krill eating the plankton, which are then eaten by sardines and anchovies. There have been a number of warnings related to shellfish domoic acid toxicity in the past. Currently in Oregon, mussel harvesting is closed along most of the coast due to elevated levels of domoic acid.

According to Shester, California's Dungeness crab industry has long been a model of sustainable fisheries management. He views it as quite unfortunate that they are being affected so negatively by a situation they didn't cause.


While the hundreds of crab fishers are not directly responsible for their current plight, they are part of the broader issue of humankind's negative impact on the oceans.

"This is a warning sign that not all is well in our oceans," said Shester. "This is at least partially caused by pollution from runoff and climate change, meaning humans are responsible."

Agricultural runoff into the ocean provides nitrates and other fertilizers that can help the harmful algae bloom.


Unusually warm ocean temperatures during what is amounting to a strong El Niño year are also being blamed for the large algae bloom giving rise to the unhealthy concentrations of toxins. While such blooms occur on a rotating basis, researchers with the National Oceanic and Atmospheric Administration said the algae bloom this summer was one of the largest ever seen on the West Coast.

In August, Fusion reported on the "warm blob" of ocean water giving rise to the algae. Washington’s state climatologist Nicholas Bond said that the waters that make up the blob are now “as warm as we’ve ever seen them off the Pacific Northwest” in recorded history. Bond did not attribute the current warm spell to climate change, but rather unusual weather patterns. However he did say the episode could be used as a learning experience and a “kind of a preview to some of the temperatures we’re liable to see much more of in the coming decades” as a result of global warming.