Harmful Algae Bloom

What Is a Red Tide?

Harmful algal blooms, or HABs, occur when colonies of algae—simple plants 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. The human illnesses caused by HABs, though rare, can be debilitating or even fatal. While many people call these blooms ‘red tides,’ scientists prefer the…