Module 4 Stream Invertebrate Survey Interpretation
Coho Creek-maple Rid, Sep 07, 2019 | Survey ID: 219
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 136
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 2
(total # counted 136) / (# of 30cm x 30cm samples x.09m2 2 / (Area: 0.18)) : 755.56
B) PREDOMINANT TAXON: Aquatic Worm, (44)
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) = 6
(# of category 3) = 6
Pollution Tolerant Index = 18
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 15 / total 136 = 0.11
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 18
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:
44 / 136 = 0.3235
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: 4
Total: 2.5

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 1 1 Caddisfly
Dobsonfly
Gilled Snail
14 3 Mayfly
Riffle Beetle
Stonefly
Water Penny
Sub Total: 15 4
Category 2 - Somewhat Pollution Tolerant Alderfly larva
12 3 Aquatic Beetle
20 1 Aquatic Sowbug
Clam, Mussel
Cranefly Larva
Crayfish
Damselfy Larva
Dragonfly Larva
Fishfly Larva
14 1 Scud
Watersnipe Larva
Sub Total: 46 5
Category 3 - Pollution Tolerant 44 3 Aquatic Worm
2 1 Blackfly Larva
Leech
2 1 Midge Larva (chironomid)
5 1 Planarian
6 2 Pouch Snail
Truebug Adult
16 1 Water Mite
Sub Total: 75 9