Sea bird mortality at Cabo San Lucas, Mexico: evidence that toxic diatom blooms are spreading.

Domoic acid was found to be responsible for an isolated event involving the massive death of brown pelicans (Pelecanus occidentalis) in January 1996, at the tip of the Baja California peninsula. The death of these sea birds was the result of feeding on mackerel (Scomber japonicus) contaminated by domoic acid-producing diatoms (Pseudonitzschia sp.). The number of dead birds (150 animals) found during a period of 5 days caused alarm and called for a governmental task force that would help to implement emergency measurements to protect other species of bird. Also, local canneries were inspected to verify the safety of their recent production and prevent the toxin entering the human market. Fortunately, the timing, response and coordination of this task force enabled identification of the origin and nature of the toxin that provoked such a phenomenon. Future monitoring is recommended to avoid a larger impact of domoic acid spreading and the occurrence of similar toxic events.