Module 4 Stream Invertebrate Survey Interpretation
Mccartney Creek, Mar 30, 1999 | Survey ID: 41
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 62
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 3
(total # counted 62) / (# of 30cm x 30cm samples x.09m2 3 / (Area: 0.27)) : 229.63
B) PREDOMINANT TAXON: Stonefly, (17)
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) = 0
(# of category 3) = 4
Pollution Tolerant Index = 13
EPT INDEX
Good Acceptable Marginal Poor
greater than 8 5 - 8 2 - 5 0 - 2
Total number of EPT taxa from Column C = 14
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 38 / total 62 = 0.61
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 22
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:
17 / 62 = 0.2742
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 2
EPT Index: 4
EPT to Total Ratio: 3
Predominant Taxon Ratio: 4
Total: 3.25

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 5 3 Caddisfly
Dobsonfly
Gilled Snail
16 7 Mayfly
Riffle Beetle
17 4 Stonefly
Water Penny
Sub Total: 38 14
Category 2 - Somewhat Pollution Tolerant Alderfly larva
Aquatic Beetle
Aquatic Sowbug
Clam, Mussel
Cranefly Larva
Crayfish
Damselfy Larva
Dragonfly Larva
Fishfly Larva
Scud
Watersnipe Larva
Sub Total: 0 0
Category 3 - Pollution Tolerant 7 2 Aquatic Worm
3 1 Blackfly Larva
Leech
12 4 Midge Larva (chironomid)
Planarian
Pouch Snail
Truebug Adult
2 1 Water Mite
Sub Total: 24 8