This summer, we learned that a warm blob of ocean water across the Eastern Pacific was feeding a massive algal bloom all the way up and down the US West Coast from Alaska to California. At the time, officials voiced concerns about domoic acid, a potentially lethal neurotoxin secreted by one of the dominant bloom species.
Now the situation appears to have gotten worse: New research shows that domoic acid is indeed making its way up the food chain, poisoning marine mammals and prompting the California Department of Public Health to warn folks off local crabs.
Domoic acid is a naturally-occurring toxin produced by the alga Pseudo-nitzschia, for reasons not yet clear to scientists. What is clear is that domoic acid is no bueno for humans. At unsafe concentrations -- above 20 parts per million for shellfish meat -- it can lead to domoic acid poisoning (DAP). Mild DAP may result in vomiting, headaches and diarrhoea, while more severe exposure can lead to amnesia, coma or death. You do not want to mess around with this stuff.
Algae bloom across the west coast this summer. Image Credit: NOAA
Yesterday, wildlife biologists reported finding domoic acid in the tissue of 36 animals stranded off the California, Washington and Oregon coasts. "We're seeing much higher contamination in the marine food web this year in this huge geographic expanse than in the past," research biologist Kathi A. Lefebvre told The New York Times. Also this week, the CDPH issued a warning about Dungeness and Rock crabs caught between Oregon and Santa Barbara, California:
Recent test results have shown persistently high levels of domoic acid in Dungeness crab and Rock crab, which have been caught along the California coastline. The levels have exceeded the State's action level for the crabs' body meat as well as the viscera, commonly referred to as crab butter, and therefore pose a significant risk to the public if they are consumed.
Like many other strange ecological phenomena the US has witnessed these last few months, the West Coast algal bloom is being fuelled by El Niño, which is going to keep surface ocean waters toasty all winter long. El Niño is dramatically reducing phytoplankton concentrations across the equatorial Pacific. As phytoplankton form the base of marine food chains, this could have an ecological domino effect, suppressing populations of seabirds, marine mammals, and yes, tasty fish.
At least all that rain will be great for fruit and veggies.
Top image: Red rock crab, via Wikimedia