Module 4 Stream Invertebrate Survey Interpretation
Patenaude Creek, Sep 24, 2018 | Survey ID: 208
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 182
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 1
(total # counted 182) / (# of 30cm x 30cm samples x.09m2 1 / (Area: 0.09)) : 2,022.22
B) PREDOMINANT TAXON: Mayfly, (115)
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) = 2
(# of category 3) = 3
Pollution Tolerant Index = 14
EPT INDEX
Good Acceptable Marginal Poor
greater than 8 5 - 8 2 - 5 0 - 2
Total number of EPT taxa from Column C = 19
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 165 / total 182 = 0.91
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 26
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:
115 / 182 = 0.6319
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 2
EPT Index: 4
EPT to Total Ratio: 4
Predominant Taxon Ratio: 2
Total: 3

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 24 6 Caddisfly
Dobsonfly
Gilled Snail
115 8 Mayfly
Riffle Beetle
26 5 Stonefly
Water Penny
Sub Total: 165 19
Category 2 - Somewhat Pollution Tolerant Alderfly larva
7 1 Aquatic Beetle
Aquatic Sowbug
Clam, Mussel
Cranefly Larva
Crayfish
Damselfy Larva
Dragonfly Larva
Fishfly Larva
Scud
Watersnipe Larva
Sub Total: 7 1
Category 3 - Pollution Tolerant 7 4 Aquatic Worm
Blackfly Larva
Leech
1 1 Midge Larva (chironomid)
2 1 Planarian
Pouch Snail
Truebug Adult
Water Mite
Sub Total: 10 6