Module 4 Stream Invertebrate Survey Interpretation
Maple Creek, Jul 18, 2016 | Survey ID: 137
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 306
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 3
(total # counted 306) / (# of 30cm x 30cm samples x.09m2 3 / (Area: 0.27)) : 1,133.33
B) PREDOMINANT TAXON: Aquatic Worm, (107)
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) = 9
2 x (# of category 2) = 10
(# of category 3) = 3
Pollution Tolerant Index = 22
EPT INDEX
Good Acceptable Marginal Poor
greater than 8 5 - 8 2 - 5 0 - 2
Total number of EPT taxa from Column C = 5
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 120 / total 306 = 0.39
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 19
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:
107 / 306 = 0.3497
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 4
EPT Index: 2
EPT to Total Ratio: 2
Predominant Taxon Ratio: 4
Total: 3

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 32 2 Caddisfly
1 1 Dobsonfly
Gilled Snail
88 3 Mayfly
Riffle Beetle
Stonefly
Water Penny
Sub Total: 121 6
Category 2 - Somewhat Pollution Tolerant Alderfly larva
2 2 Aquatic Beetle
10 1 Aquatic Sowbug
Clam, Mussel
4 1 Cranefly Larva
Crayfish
Damselfy Larva
Dragonfly Larva
Fishfly Larva
39 1 Scud
1 1 Watersnipe Larva
Sub Total: 56 6
Category 3 - Pollution Tolerant 107 3 Aquatic Worm
Blackfly Larva
Leech
Midge Larva (chironomid)
Planarian
4 3 Pouch Snail
Truebug Adult
18 1 Water Mite
Sub Total: 129 7