Harmful algal bloom on Lake Erie expected to be severe

Jul 12, 2019

The National Oceanic and Atmospheric Administration and its research partners are forecasting that western Lake Erie will experience a significant harmful algal bloom (HAB) this summer. Most of the rest of the lake will not be affected.

In its forecast released Thursday, NOAA said this year’s bloom is expected to measure 7.5 on the severity index, but could range between 6 and 9. An index above 5 indicates blooms having greater impact. Te federal agency said the largest blooms occurred in 2015, with a severity index of 10.5.

"This year, the lake temperature has remained relatively cool due to the higher-than-average rainfall in the region, so the bloom is not expected to start until late July when the water temperature reaches 65 to 70 degrees," NOAA said. "This contrasts with 2018, when exceptionally warm weather at the beginning of June caused an early start."

Credit National Oceanic and Atmospheric Administration

NOAA said Lake Erie blooms consist of blue-green algae that are capable of producing a liver toxin that poses a risk to human and wildlife health. Blooms may also result in higher costs for cities and local governments that need to treat drinking water, prevent people from enjoying fishing, swimming, boating and visiting the shoreline, and harm the region’s summer tourism economy.

"The size of a bloom isn’t necessarily an indication of how toxic it is," the agency said. "For example, the toxins in a large bloom may not be as concentrated as in a smaller bloom. Each algal bloom is unique in terms of size, toxicity, and ultimately its impact to local communities. NOAA is actively developing tools to detect and predict how toxic blooms will be."