Module 4 Stream Invertebrate Survey Interpretation
Macdonald Creek, Jul 07, 2013 | Survey ID: 14
A) ABUNDANCE AND DENSITY
ABUNDANCE total number of organisms from Column B: 198
DENSITY invertebrate density per square meter
# of 30cm x 30cm samples: 1
(total # counted 198) / (# of 30cm x 30cm samples x.09m2 1 / (Area: 0.09)) : 2,200.00
B) PREDOMINANT TAXON: Mayfly, (82)
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) = 3
Pollution Tolerant Index = 12
EPT INDEX
Good Acceptable Marginal Poor
greater than 8 5 - 8 2 - 5 0 - 2
Total number of EPT taxa from Column C = 6
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 169 / total 198 = 0.85
D) DIVERSITY ASSESSMENT
Total Number of Taxa: 14
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:
82 / 198 = 0.4141
SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 2
EPT Index: 3
EPT to Total Ratio: 4
Predominant Taxon Ratio: 3
Total: 3

Field Data as Collected
Polution Tolerance
Number Counted
Number of Taxa
Common Name
Category 1 - Polution Intolerant 6 2 Caddisfly
Dobsonfly
1 Gilled Snail
82 2 Mayfly
Riffle Beetle
81 2 Stonefly
Water Penny
Sub Total: 170 6
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 16 5 Aquatic Worm
1 1 Blackfly Larva
Leech
Midge Larva (chironomid)
Planarian
Pouch Snail
Truebug Adult
11 2 Water Mite
Sub Total: 28 8