Marine News from the Great Lakes

What You Need to Know about “HABs”

Published: Friday, July 8, 2016

What You Need to Know about “HABs”

Harmful algal blooms have been brought into the national spotlight as large blooms have been observed in Lake Erie and elsewhere throughout the country. While much is yet to be studied, Ohio has made significant advances in understanding blooms, as well as developing best practices to help prevent them. Below is an overview of HABs as well as some helpful tools and tips for enjoying a safe boating season on the water!

What is a harmful algal bloom?

  • A harmful algal bloom, or HAB, is any large increased density of algae that is capable of producing toxins. In freshwater, such as Lake Erie, those algae tend to be cyanobacteria, more commonly known as blue-green algae, which are always present in the water to some extent but grow excessively under certain conditions. The “harmful” in HAB comes from toxins produced by the cyanobacteria. Most harmful algal blooms occur in mid-to-late summer, when spring rains have brought nutrients –such as phosphorus and nitrogen – to our waterways and water temperatures reach above 60 degrees Fahrenheit.

If toxins have been detected in one part of the lake, is the water in the whole lake unsafe?

  • Toxin can persist in the water for more than 30 days, but is rapidly diluted and quickly reaches safe levels as the bloom dissipates and also as you move away from the bloom. Water treatment plants in Lake Erie’s western basin routinely monitor the water they bring in for human use, so affected areas can know about a problem quickly.

Are fish in a harmful algal bloom safe to eat?

  • As long as standard guidelines are followed, such as properly cleaning and rinsing fish fillets, the Ohio Department of Natural Resources considers fish from the lake safe to eat.

What tools are available for boaters?

What can I do to help?

  • When detergents are necessary, use soaps that are phosphate free, biodegradable, and non-toxic.
  • Use restrooms onshore, and when underway, use approved MSDs or portable toilets.
  • Conserve water when washing your boat and put a spray nozzle on your hose.

For more information about Harmful Algal Blooms, visit the Ohio Sea Grant website,

tags: Environmental Impact

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