EPA 820-F-17-010
Example 2: Recreational water managers in Indiana use a 4-level alert system, based on testing results. Signs
contain information on how to identify a harmful algal bloom (HAB), and the effects a HAB may have on
people, pets and fish.
Does the Beach Have Blue-green Algae?
Blue-green algae can be found in many of Indiana's lakes and reservoirs. Swimmers,
boaters and pet owners can enjoy water based recreation, but should be on the lookout
for evidence of harmful algal blooms (HABs).
Blue-Green Algae
Algae of many species occur naturally in Indiana's lakes
and reservoirs. Blue-green algae is common and not a
problem unless levels are high. When levels are high,
toxins may be produced as algae cells grow and die.
What Does Blue-Green Algae Look Like?
When conditions are right, HABs may occur. An HAB occurs when algae reproduce
quickly, creating mats of algae or discoloration of the water because of the large
quantity of algae cells present. High nutrient levels from lawn and agricultural
fertilizers, sunlight and warm, shallow water all contribute to HABs.
Colors may vary from green, blue-green, brown, black, white, purple, red or black.
How Can Exposure to High Levels of Blue-Green Algae
Affect People, Pets and Fish?
Algae may look like a film, crust, puff balls, grass clippings, dots, spilled paint, pea
soup, foam, wool, streaks or cottage cheese curds.
Watch for signs that might indicate a blue-green algae bloom in this lake or
reservoir and report your sighting to the property office.
Pet Owners
Pets can be poisoned by
the toxins produced by
some algae.
Precautions:
Do not allow your pets to
swim in or drink water
where algae is present.
Rinse pets with soap and
water if they swim in
murky water.
Do not let your pet lick
algae off their fur.
Fishing
Some toxins may
accumulate in the tissues
of ffsh.
Precautions:
Do not cut into organs
when filleting your fish.
Rinse the fillets with
clean water before
freezing or cooking.
Avoid consuming the
guts, where toxin
accumulation is greatest.
Eat in moderation.
Today's Alert Level
Precautions:
Avoid contact with
algae.
Avoid swallowing water
while swimming.
Take a bath or shower
with warm, soapy water
after coming in contact
with lake water
Do not use lake water
for cooking or bathing.
Blue-green algae and toxin levels are tested in this body
of water. Alert levels vary with testing results:
Swimmers and
boaters
LOW RISK
Don't drink the water
Shower after you swim
US Army Corps
of Engineers
IDEM
RESERVOIRS
Photos courtesy of IDEM and DNH
ADVISORY
Swimming and boating permitted.
Avoid contact with algae.
Avoid swallowing water while swimming.
Take a bath or shower with warm soapy water after
coming in contact with lake water.
Do not use lake water for cooking or bathing.
Do not allow your pets to swim in or drink water
where algae are present.
CAUTION
All Recreation Advisory
precautions, plus . . .
Children and those with
compromised immune systems
should not swim.
BEACH CLOSED
Algae and toxin levels make this
beach currently unsafe for
swimming.
ADVISORY
Don't drink the water. Shower
after you swim. Keep pets
out of the water.
Indiana's lakes and reservoirs provide great recreational
opportunities. Learn to recognize blue-green algae, be
alert, take precautions and have fun on the water!

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