Module 4 Stream Invertebrate Survey Interpretation
Mcleod River, Jun 17, 2001 | Survey ID: 167
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 55
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 1
(total # counted 55) / (# of 30cm x 30cm samples x.09m2 1 / (Area: 0.09)) : 611.11
B) PREDOMINANT TAXON: Mayfly, (31)
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 = 3
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 39 / total 55 = 0.71
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 9
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:
31 / 55 = 0.5636
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 3
EPT Index: 2
EPT to Total Ratio: 3
Predominant Taxon Ratio: 3
Total: 2.75

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 2 1 Caddisfly
Dobsonfly
Gilled Snail
31 1 Mayfly
Riffle Beetle
6 1 Stonefly
Water Penny
Sub Total: 39 3
Category 2 - Somewhat Pollution Tolerant Alderfly larva
Aquatic Beetle
Aquatic Sowbug
Clam, Mussel
1 1 Cranefly Larva
Crayfish
Damselfy Larva
1 1 Dragonfly Larva
3 1 Fishfly Larva
Scud
Watersnipe Larva
Sub Total: 5 3
Category 3 - Pollution Tolerant 4 1 Aquatic Worm
Blackfly Larva
Leech
Midge Larva (chironomid)
1 1 Planarian
Pouch Snail
Truebug Adult
6 1 Water Mite
Sub Total: 11 3