Module 4 Stream Invertebrate Survey Interpretation
Maple Creek, Jul 25, 2017 | Survey ID: 184
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 123
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 3
(total # counted 123) / (# of 30cm x 30cm samples x.09m2 3 / (Area: 0.27)) : 455.56
B) PREDOMINANT TAXON: Aquatic Sowbug, (48)
C) WATER QUALITY ASSESSMENTS
POLLUTION TOLERANT INDEX
Good Acceptable Marginal Poor
greater than 22 22 - 17 17 -11 less than 11
3 x (# of category 1) = 6
2 x (# of category 2) = 10
(# of category 3) = 4
Pollution Tolerant Index = 20
EPT INDEX
Good Acceptable Marginal Poor
greater than 8 5 - 8 2 - 5 0 - 2
Total number of EPT taxa from Column C = 4
EPT TO TOTAL RATIO
Good Acceptable Marginal Poor
0.75 - 1.00 0.50 - 0.75 0.25 - 0.50 0 - 0.25
# of EPT 7 / total 123 = 0.06
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 15
PREDOMINANT TAXON RATIO
Good Acceptable Marginal Poor
0 - 0.40 0.40 - 0.60 0.60 - 0.80 0.80 - 1.0
PREDOMINANT TAXON RATIO:
48 / 123 = 0.3902
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 3
EPT Index: 2
EPT to Total Ratio: 1
Predominant Taxon Ratio:
Total: 1.5

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 5 3 Caddisfly
Dobsonfly
Gilled Snail
2 1 Mayfly
Riffle Beetle
Stonefly
Water Penny
Sub Total: 7 4
Category 2 - Somewhat Pollution Tolerant13 1 Alderfly larva
Aquatic Beetle
48 1 Aquatic Sowbug
Clam, Mussel
Cranefly Larva
1 1 Crayfish
Damselfy Larva
1 1 Dragonfly Larva
Fishfly Larva
28 1 Scud
Watersnipe Larva
Sub Total: 91 5
Category 3 - Pollution Tolerant 6 2 Aquatic Worm
Blackfly Larva
Leech
15 2 Midge Larva (chironomid)
Planarian
1 1 Pouch Snail
Truebug Adult
3 1 Water Mite
Sub Total: 25 6