After analyzing how the Dungeness crab high neurotoxin levels were caused by El Niño, a professor from the University of California – Santa Cruz is now attempting to create a forecasting model. This will help scientists and marine biologists predict when a domoic acid neurotoxin outbreak will happen and how long it will last.
Domoic acid concentration levels increase in waters due to blooms of toxic microscopic algae. Once these die off, they contaminate the ocean’s bed and eventually get eaten by crabs. These blooms are greatly influenced by El Niño’s strength, as well as duration.
This could be easily seen last year when all Dungeness crab retailers were forced to pull their product from the market. Even now, several stores are still shut down because the crabs’ toxicity has not reached normal levels at all, mainly due to the fact that large quantities of algae are still present in some coastal waters.
Although some regions have restarted their crab commercialization, the CDC still advises people to remove the viscera and to use specific cooking methods, removing broiling or grilling completely, as well as disposing of the water used in the cooking process. According to the UCSC prof. Raphael Kudela who conducted this analysis, it will still take at least a couple of months before the crab ban gets removed for all Californian stores and fisheries.
The algae bloom, the largest one ever recorded up to this point, was mainly caused by an oceanographical anomaly informally called a “warm blob”. This phenomenon can be described as an increase in warm water temperatures limited to only one specific region.
The “warm blob”’s appearance in Californian waters is extremely unusual if one would take into account that this phenomenon is stopped by the region’s upwelling of cold waters caused by high-driven winds. Unfortunately, in 2013, a blob appeared in the North Pacific only to be joined by another one that developed in 2014 in Southern California.
In 2015, these two blobs collided in order to create a more massive phenomenon that eventually lead to the largest recorded toxic algae bloom, lasting from April until October. These blooms usually happen for limited periods of time in Summer and Fall, but last year, the warm waters allowed algae to reproduce at a heightened level for extended periods, contaminating the ocean floor even more along the way.
Because the fact that the Dungeness crab high neurotoxin levels were caused by El Niño is no longer the case all across Calfornia, the ban has been more or less entirely lifted. But in some cases, waters still have abnormal levels of domoic acid neurotoxin. Hopefully, this will no longer be present in the following months, allowing Californian citizens to partake in crab consumption once again, without the fear of ingesting high amounts of neurotoxin.