Module 4 Stream Invertebrate Survey Interpretation

MCDONALD CREEK-WestV | Survey ID: 135

A) Abundance and density

ABUNDANCE: 254 / NUMBER OF SAMPLES: (2 *.09) = DENSITY: 1,411.11

B) PREDOMINANT TAXON

Mayfly Larva

C) WATER QUALITY ASSESSMENTS

POLLUTION TOLERANT INDEX
Good Acceptable Marginal Poor
greater than 22 22 - 17 16 - 11 less than 11
3 x (# of category 1) = 9
2 x (# of category 2) = 8
(# of category 3) = 5
= 22

EPT INDEX
Good Acceptable Marginal Poor
greater than 8 5 - 8 2 - 5 0 - 1
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 199 / total 254 = 0.78

D) DIVERSITY ASSESSMENT

TOTAL NUMBER OF TAXA: 18

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: Predominant Taxa 149 / 254 = 0.5866

SITE ASSESMENT RATING
Good Acceptable Marginal Poor
4 3 2 1
Pollution Tolerance Index: 4
EPT Index: 3
EPT to Total Ratio: 4
Predominant Taxon Ratio: 3
Total: 3.5

Field Data as Collected

Polution Tolerance

Number Counted

Number of Taxa

Common Name

Category 1 - Polution Intolerant 1 1 Caddisfly
Dobsonfly
Gilled Snail
149 3 Mayfly
Riffle Beetle
49 2 Stonefly
Water Penny
Sub Total: 199 6 3
Category 2 - Somewhat Pollution Tolerant Alderfly larva
1 1 Aquatic Beetle
1 1 Aquatic Sowbug
Clam, Mussel
1 1 Cranefly Larva
Crayfish
Damselfy Larva
Dragonfly Larva
Fishfly Larva
4 1 Scud
Watersnipe Larva
Sub Total: 7 4 4
Category 3 - Pollution Tolerant 29 3 Aquatic Worm
Blackfly Larva
Leech
8 2 Midge Larva (chironomid)
2 1 Planarian
1 1 Pouch Snail
Truebug Adult
8 1 Water Mite
Sub Total: 48 8 5
Total: 254 18 12