Module 4 Stream Invertebrate Survey Interpretation
Maple Creek, Nov 11, 2008 | Survey ID: 5
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 356
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 3
(total # counted 356) / (# of 30cm x 30cm samples x.09m2 3 / (Area: 0.27)) : 1,318.52
B) PREDOMINANT TAXON: Scud, (189)
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) = 4
Pollution Tolerant Index = 23
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 47 / total 356 = 0.13
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 21
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:
189 / 356 = 0.5309
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 4
EPT Index: 2
EPT to Total Ratio: 1
Predominant Taxon Ratio: 3
Total: 2.5

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 9 1 Caddisfly
Dobsonfly
Gilled Snail
38 4 Mayfly
1 1 Riffle Beetle
Stonefly
Water Penny
Sub Total: 48 6
Category 2 - Somewhat Pollution Tolerant1 1 Alderfly larva
1 1 Aquatic Beetle
3 1 Aquatic Sowbug
Clam, Mussel
2 2 Cranefly Larva
Crayfish
Damselfy Larva
Dragonfly Larva
Fishfly Larva
189 3 Scud
Watersnipe Larva
Sub Total: 196 8
Category 3 - Pollution Tolerant 73 3 Aquatic Worm
Blackfly Larva
Leech
4 1 Midge Larva (chironomid)
Planarian
23 2 Pouch Snail
Truebug Adult
12 1 Water Mite
Sub Total: 112 7