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Harmful Algal Blooms reported at Ackley Lake State Park

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ackley lake state park
Posted at 12:50 PM, Aug 24, 2022
and last updated 2022-08-24 14:51:00-04

GREAT FALLS — An August 18, Montana Fish, Wildlife, and Parks was notified by the Montana Department of Environmental Quality (DEQ) of a blue-green bloom at Ackley Lake State Park in Judith Basin County.

FWP said in a news release that these algal blooms are not uncommon in waters across central or eastern Montana as we head into late summer and early fall.

These outbreaks are known as Harmful Algal Blooms (HABs), as they sometimes pose health risks for people, pets, livestock, and wildlife.

What are Harmful Algal Blooms (HABs)?
According DEQ, HABs are caused by blue-green algae that are native to Montana’s freshwater lakes and reservoirs. They are not “Aquatic Invasive Species.” Scientists believe the blooms are occurring at more locations, however, with increased frequency and longer duration than they have in the past. Causes may include warmer water temperatures, longer summer growing seasons and increased nitrogen and phosphorus runoff from a variety of human activities.

Some algae can create toxins that may harm people and animals. Use caution during a HAB event (or a potential HAB event) as your health can be impacted when you are near the water, consume the water, or swim in the water.

What does a HAB look like?
Blue-green algae blooms often look like pea soup, grass clippings, or green latex paint. The algae are usually suspended in the water column or aggregated into floating mats. The bloom can be many colors including green, blue, gold, or red.

Not all varieties of blue-green algae are harmful, but some, under certain conditions, can produce dangerous cyanotoxins. The following are some recommendations and considerations concerning HABs:

  • Do not drink, swallow, or swim in water that shows signs of a HAB and be sure to keep kids and pets or livestock out.
  • Direct contact, ingestion or inhalation of cyanotoxins may irritate the skin, eyes, nose, throat and respiratory system, or cause nausea, vomiting, diarrhea, headache or liver and kidney damage.
  • Harmful algal blooms pose an unknown health risk to humans through fish consumption. 
  • If you suspect a HAB-related illness in a person or animal, call Poison Control immediately at 1-800-222-1222.
  • When in doubt, stay out!

Similar algal blooms have been reported recently at Canyon Ferry Lake and Hauser Lake. To learn more about or to report a suspected HAB, click here.


ackley lake state park