Pseudo-Nitzschia: Emerging Harmful Algae Bloom Threat in the Gulf of Maine

In July, 2003 more than twenty whales died on Georges Bank while additional whales and forty-two seals were found dead in the near-shore waters of Maine. Domoic acid derived from a pinnate marine diatom known as Pseudo-nitzschia sp. is believed to be the cause of these mortalities. Humans, marine mammals, and birds are susceptible to domoic acid, which causes amnesic shellfish poisoning. The first cases of amnesic shellfish poisoning were reported in 1987 on Prince Edward Island, and high levels of domoic acid have been found in areas of the Gulf of Maine on multiple occasions since then. Developing an understanding of where the acid is coming from and the tools to monitor for it or its producers is imperative to protecting seafood consumers from humans to whales. While some species of Pseudo-nitzschia are capable of producing domoic acid, not all are, creating the need to know what species are found in the Gulf of Maine and which of them are toxic. Molecular techniques were used to identify Pseudo-nitzschia to the species level. The LSU D1-D3 region of numerous samples of Pseudo-nitzschia collected throughout the Gulf of Maine was sequenced and the resulting sequences were compared to sequences in NCBI's GenBank. Out of the sixty-three sequences resembling Pseudo-nitzschia, four unique sequences were found which each reflect different species or strains. The sequences were also used to determine that molecular probes for species identification developed on the west coast do not match the east coast strains.