Alexandrium spp.

Chain of Alexandrium catanella cells. Photo credit: Melissa Carter

Toxin Produced:  Saxitoxins

Syndrome:  Paralytic shellfish poisoning

This toxin was first discovered in 1927 after a shellfish poisoning event affected over one hundred people in central California. Saxitoxin is now recognized as one of the most deadly algal toxins.

The dinoflagellate Alexandrium catanella (formerly Gonyaulax catanella/catenatum) produces saxitoxin, a highly potent neurotoxin which, if consumed, causes paralytic shellfish poisoning (PSP). Ingestion of saxitoxin by humans, primarily through eating shellfish, can result in numbness, ataxia, incoherence, and in extreme cases, respiratory paralysis and death.