1. Little Creatures that tell us If our natural waterways are healthy
Macroinvertebrates
Little Creatures that tell us
If our natural waterways are healthy

2. Benthic Macroinvertebrates
Benthic means: living at the bottom of a body of water (stream, river, pond)
Macro- large
Invertebrate- animal without backbone
Macroinvertebrate- large water dwelling invertebrate able to be seen without a microscope

3. What are Macroinvertebrates?
Organisms that have no backbone
Visible without a microscope
Found in Fresh Water Streams
Eats leaves & algae in stream
Source of Energy for larger animals

4. What are Macroinvertebrates?
Snails
Crayfish
Worms
Fly larva
Mayfly, caddisfly, stone fly larva
Clams
Water beetles

5. Indicator Species Indicator Species means…
They tell scientists when there is a problem in nature- specifically the stream environment
The problem being pollution

6. Why are Macroinvertebrates Important?
Source of Energy for larger animals
Brook Trout or other fish eats them…
Then fish are eaten by birds, raccoons, humans
Helps with the Food Web

7. Where do Macroinvertebrates live?
Bottom of a Stream
Attached to rocks
Attached to plants
In fast moving water, need oxygen

8. Why are Macroinvertebrates Important?
They are good indicators of the stream’s overall health
These animals are different sizes, shapes, and have different adaptations that make it easy for scientists to learn if a stream is healthy

9. Why do they need clean water?
To survive the macroinvertebrates that show that the water is clean need…
Lots of oxygen to survive
Poor oxygen, they die and provide no food for the Trout, kingfishers, Salmon, etc.
Those macroinvertebrates that need poor dirty water to survive-
tell scientists that the water is polluted

10. Macroinvertebrates

11. What do Macroinvertebrates tell Scientists about a Stream?
Some macroinvertebrates are only found in Healthy untouched waters- not polluted- these tell scientists that the water is pure and good
Others are found in moderate or OK waters- these may have some pollutants- they tell the scientists that the water is starting to get worse
Also other macroinvertebrates only survive in poor water, this tells scientists that the water quality is poor and needs help

12. Which Macroinvertebrates tell that there is good quality water?
Different kinds of stoneflies, mayflies, and caddisflies tell a scientist the stream is healthy.
Scientists look for a variety of the above

13. Stonefly Larva

14. Which macroinvertebrates do you find in a Moderately clean Stream?
The number of different macroinvertebrates becomes less as pollution rises
There will be fewer stoneflies, many fewer mayflies, and only some types of caddisflies
Soft-bodied worms and fly larva also increase
Beetles are probably still in the stream; mollusks are not.

15. What macroinvertebrates are in poor quality streams?
Stoneflies are not present at all
A few mayflies and caddisflies- may be there
Most found are soft-bodied animals: fly larvae, leeches and planaria (round worm, tape worm).
Amphipod- fast moving shrimp looking creature

16. Macroinvertebrate Identification Key GROUP 1 DO NOT TOLERATE POLLUTION
Stonefly nymph
5-35mm
Caddisfly larva
2-40mm
Mayfly nymph
3-10mm
Alderfly nymph
10-25mm
Fishfly larva
5-16mm
Stonefly adult
10-40mm
Caddisfly adult
14-25mm
Mayfly adult
5-25mm
Alderfly adult
24-50mm
Water penny
4-6mm
Hellgrammite
(dobsonfly larva)
25-90mm
Freshwater mussel
2-250mm
Pouch snail
2-70mm
Ramshorn snail
Snipe fly larva
12-18mm

17. Macroinvertebrate Identification Key GROUP 2 TOLERATE SOME POLLUTION
Dragonfly larva
15-50mm
Damselfly larva
10-50mm
Water beetle larva
2-6mm
Whirligig beetle
3-15mm
Riffle beetle adult
2-4mm
Dragonfly nymph
30-50mm
Damselfly nymph
Water beetle
3-40mm
Whirligig beetle larva
3-12mm
Water strider
10-25mm
Dragonfly adult
17-200mm
Damselfly adult
25-55mm
Backswimmer
5-16mm
Waterboatman
Cranefly larva
Scud (amphipod)
5-21mm
Crayfish
10-150mm
Water scorpion
20-43mm
Sowbug
5-22mm
Freshwater clam
30-270mm

18. Macroinvertebrate Identification Key GROUP 3 TOLERATE POLLUTION
Blackfly larvae
3-12mm
Midge larva
2-15mm
Mosquito larva
1-6mm
Flatworm (planaria)
Freshwater worm
1-30mm
Blackfly adult
2-5mm
Midge adult
3-4mm
Mosquito adult
6-13mm
Leech
5-40mm
Water snail
2-70mm

19. Macroinvertebrate means…
Small creature that you need a microscope to see
Small creature that you can see without a microscope
Small creature that lives on land
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20. Benthic means… Living at the bottom of a stream
Living on land, near a stream
Living by floating in a stream of 21

21. Macroinvertebrates tell if a stream is healthy or not.
True
False
Unsure
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22. A sample of a Macroinvertebrate is…
Small bird
Mayfly larva
Butterfly larva
Turtle of 21

23. Macroinvertebrates that tell if water is clean need only a little bit of oxygen
True
False
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24. Macroinvertebrates that survive in low oxygen water tell scientists
The water is polluted
The water is clean
That it is water of 21

25. Large amounts of caddisfly larva, mayfly larva, and stone fly larva are found in…
Polluted water
Moderately clean water
Healthy, good quality water
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26. Smaller amounts of caddisfly, mayfly and stone fly larva, along with some worms are in this type of water
Polluted water
Moderately clean water
Healthy, good quality water
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27. Stoneflies are not present at all, more leeches, and fly larvae are found in this stream
Polluted water
Moderately clean water
Healthy, good quality water
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