Module 4 Stream Invertebrate Survey Interpretation
Alouette River, Jun 22, 2024 | Survey ID: 270
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 45
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 1
(total # counted 45) / (# of 30cm x 30cm samples x.09m2 1 / (Area: 0.09)) : 500.00
B) PREDOMINANT TAXON: Water Mite, (12)
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) = 6
(# of category 3) = 3
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 = 7
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 19 / total 45 = 0.42
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 16
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:
12 / 45 = 0.2667
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 3
EPT Index: 3
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 1 1 Caddisfly
0 0 Dobsonfly
0 0 Gilled Snail
11 3 Mayfly
0 0 Riffle Beetle
7 3 Stonefly
0 0 Water Penny
Sub Total: 19 7
Category 2 - Somewhat Pollution Tolerant0 0 Alderfly larva
2 2 Aquatic Beetle
1 1 Aquatic Sowbug
0 0 Clam, Mussel
0 0 Cranefly Larva
0 0 Crayfish
0 0 Damselfy Larva
0 0 Dragonfly Larva
0 0 Fishfly Larva
2 1 Scud
0 0 Watersnipe Larva
Sub Total: 5 4
Category 3 - Pollution Tolerant 4 3 Aquatic Worm
0 0 Blackfly Larva
0 0 Leech
5 1 Midge Larva (chironomid)
0 0 Planarian
0 0 Pouch Snail
0 0 Truebug Adult
12 1 Water Mite
Sub Total: 21 5