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HAB Species by Name

The below table lists major HAB species and their impacts to human health, wildlife, ecosystems, and economies.  This information is adapted from the IOC UNESCO Taxonomic Reference List (please visit the the IOC Harmful Algal Programme for additional information:

To view information organized by HAB poisoning syndrome/impact, please click here.  Additional information regarding freshwater HAB taxa can be found on the EPA's CyanoHAB website:

Causative OrganismToxin/Bioactive CompoundHuman Health Effects and/or SyndromeImpacts to wildlife and/or domestic animalsEcosystem Disruption ImpactsEconomic ImpactsImpacted Areas in U.S.
Akashiwo sanguineumSurfactantsSuspected respiratory irritantMigratory bird deaths, including protected speciesWater discoloration; Foam formationRehabilitation of protected bird speciesPacific Coast
Alexandrium monilatum
GoniodominFish and shellfish mortalityWater discolorationGulf of Mexico and Atlantic coast up to New Jersey
Alexandrium*; Gymnodinium*; Pyrodinium bahamense SaxitoxinsRespiratory paralysis, death (Paralytic Shellfish Poisoning or PSP)Marine mammal deathsLoss of shellfish harvesting income; human illness from recreational harvest; closure recreational puffer fish harvest in FLPacific coast, including Alaska; NE Atlantic coast;
Anabaena, Aphanizomenon, and Nostoc sp.Anatoxins, saxotoxinsNeurotoxin, respiratory paralysisIllnesses or deaths among livestock, dogs, waterfowl, and fish Impacts to fish and waterfowlWidespread in freshwater systems; Great Lakes
Aureococcus anophagefferens --Long Island Brown TideNot characterizedWater discoloration; seagrass and shellfish die-offs; hypoxic zonesLoss of shellfish harvesting income; interference with restorationMid-Atlantic coast
Aureoumbra lagunensis --Texas Brown Tide
Not characterized: extracellular polymeric substance (EPS); possibly other uncharacterized compoundsWater discoloration; Loss of submerged aquatic vegetationTexas, Florida
AzadiniumAzaspiracid toxinsGastrointestinal impacts, cytotoxic, possible teratogen and carcinogen; (Azaspiracid shellfish poisoning or AZP)Pacific northwest
CylindrospermopsisCylindrospermopsins, saxitonsHepatotoxin, kidney damage, neurotoxinDog, fish kills, bird illnessImpacts to fish and waterfowlLoss of livestock and petsFreshwater systems
Dinophysis; Prorocentrum*Okadaic acid; DinophysotoxinsGastrointestinal distress (Diarrhetic Shellfish Poisoning or DSP)Closing of shellfish fisheriesOregon, Texas, Washington, Long Island Sound; New England
Gambierdiscus*CiguatoxinsSensory and gastrointestinal dysfunction (Ciguatera Poisoning or CP) Unknown; Possible impacts to monk sealsBans on fish sales from affected areas, cost of medical treatment, loss of protein sourceFlorida, Gulf Coast, Hawaii, Pacific, and Caribbean
Heterosigma akashiwoIchthyotoxinsFish killsWater discolorationLoss of fish net pen maricultureWashington; Mid-Atlantic coast
BrevetoxinsNeurotoxicity; Gastrointestinal and sensory effects (Neurotoxic Shellfish Poisoning or NSP), respiratory effectsFish kills; manatee, dolphin, marine turtle, and bird deathsWater discolorationLoss of tourism income; Removal of dead fish from beaches, shellfisheries closing, increased emergency room visits due to respiratory and gastrointestinal illness, wildlife rehabilitationGulf of Mexico and Atlantic coast up to Delaware
KarlodiniumKarlotoxinsFish killsWater discolorationAtlantic and Gulf Coasts
Lyngbyatoxin, Aplysiatoxin, debromoaplysiatoxinDermatitis, gastro-intestinal inflammatory toxinsLivestock deaths (horses), may contribute to fibropapillomatosis in turtlesPossible tourism impacts (beachgoers)Benthic mats in marine and freshwater systems
Macroalgae (Sargassum and Cladophora)H2S, dopamineRespiratory impacts, odorsImpair nesting protected speciesShade submerged aquatic vegetation, overgrow coral reefs and seagrasses, cause hypoxiaHigh biomass necessitating removal from beaches; loss of tourism incomeAll coasts
Reactive oxygen species (ROS); possibly other uncharacterized compoundsFish killsWater discolorationSevere impacts on fish and shellfish maricultrue in AsiaWest Coast, Mid-Atlantic
Marine cyanobacteria (formerly Lyngbya)DermatotoxinsImpact divers on coral reefsOvergrow coral reefsLoss of tourism incomeSouth Florida
MicrocystisMicrocystinsHepatotoxin, damage to kidney and reproductive system, carcinogenic potentialIllnesses and deaths among livestock, dogs, and fish Impacts to fish and waterfowlDrinking water supply disruption, loss of livestock and pets, recreational fishing lossesWidespread in freshwater systems; Great Lakes
OstreopsisOstreocin (palytoxin analogs)Respiratory problems, skin irritation, flu-like symptoms, deathPossible invertebrate mass mortalities and animal deathsLoss of macroalgae and benthic organisms Loss of tourism income; costs medical treatmentCaribbean, Hawaii, Gulf of Mexico
Other Raphidophytes: Chattonella, FibrocapsaIchthyotoxins; BrevetoxinsFish killsWater discolorationMid-Atlantic coast
PlanktonthrixSaxitoxins, microcystinsNeurotoxin, respiratory paralysisWidespread in freshwater systems; Great Lakes
Prorocentrum minimum--Mahogany TidesNot characterizedMortality of spat in shellfish hatcheriesWater discolorationLoss to shellfish hatcheriesChesapeake Bay
Pseudo-nitzschiaDomoic AcidGastrointestinal and central nervous system effects (Amnesic Shellfish Poisoning or ASP)Mass mortality of fish and shellfish, seabird and marine mammal mortalityClosure of shellfish harvesting, loss of tourism income, wildlife rehabilitationWest Coast, Florida, New England

*only some species within the genus produce toxins