Blooms of harmful algae, like this 'red tide' off the coast of Texas, can cause illness and death in humans and animals.

Harmful Algal Blooms: Regional Information

If you live near the coast or the Great Lakes, you've probably experienced a harmful algal bloom — HAB for short. HABs occur when algae — simple photosynthetic organisms that live in the sea and freshwater — grow out of control while producing toxic or harmful effects on people, fish, shellfish, marine mammals, and birds. Visit our new portal for region-specific HAB information, links, and resources.

Go There