Module 4 Stream Invertebrate Survey Interpretation
BOWKER CREEK | Survey ID: 237
A) Abundance and density
ABUNDANCE: 231 / NUMBER OF SAMPLES: (3 *.09) = DENSITY: 855.56
B) PREDOMINANT TAXON
Midgefly 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) = 42
2 x (# of category 2) = 44
(# of category 3) = 16
= 102
EPT INDEX
Good
Acceptable
Marginal
Poor
greater than 8
5 - 8
2 - 5
0 - 1
Total number of EPT taxa from Column C = 1
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
33 / total
231 =
0.14
D) DIVERSITY ASSESSMENT
TOTAL NUMBER OF TAXA: 26
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 66 / 231 = 0.2857
SITE ASSESMENT RATING
Good
Acceptable
Marginal
Poor
4
3
2
1
Pollution Tolerance Index: 4
EPT Index: 1
EPT to Total Ratio: 1
Predominant Taxon Ratio: 4
Total: 2.5
| POLLUTION TOLERANT INDEX | |||
|---|---|---|---|
| Good | Acceptable | Marginal | Poor |
| greater than 22 | 22 - 17 | 16 - 11 | less than 11 |
3 x (# of category 1) = 42
2 x (# of category 2) = 44
(# of category 3) = 16
= 102
2 x (# of category 2) = 44
(# of category 3) = 16
= 102
| EPT INDEX | |||
|---|---|---|---|
| Good | Acceptable | Marginal | Poor |
| greater than 8 | 5 - 8 | 2 - 5 | 0 - 1 |
| 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
33 / total
231 =
0.14
| PREDOMINANT TAXON RATIO | |||
|---|---|---|---|
| Good | Acceptable | Marginal | Poor |
| 0 - 0.40 | 0.40 - 0.60 | 0.60 - 0.80 | 0.80 - 1.0 |
| SITE ASSESMENT RATING | |||
|---|---|---|---|
| Good | Acceptable | Marginal | Poor |
| 4 | 3 | 2 | 1 |
Pollution Tolerance Index: 4
EPT Index: 1
EPT to Total Ratio: 1
Predominant Taxon Ratio: 4
Total: 2.5
EPT Index: 1
EPT to Total Ratio: 1
Predominant Taxon Ratio: 4
Total: 2.5
Field Data as Collected
Polution Tolerance |
Number Counted | Number of Taxa | Common Name |
| Category 1 - Polution Intolerant | 33 | 1 | Caddisfly |
| 0 | 0 | Dobsonfly | |
| 0 | 0 | Gilled Snail | |
| 0 | 0 | Mayfly | |
| 0 | 0 | Riffle Beetle | |
| 0 | 0 | Stonefly | |
| 0 | 0 | Water Penny | |
| Sub Total: | 33 | 1 | 14 |
| Category 2 - Somewhat Pollution Tolerant | 0 | 0 | Alderfly larva |
| 0 | 0 | Aquatic Beetle | |
| 19 | 1 | Aquatic Sowbug | |
| 0 | 0 | Clam, Mussel | |
| 0 | 0 | Cranefly Larva | |
| 1 | 1 | Crayfish | |
| 0 | 0 | Damselfy Larva | |
| 0 | 0 | Dragonfly Larva | |
| 0 | 0 | Fishfly Larva | |
| 49 | 4 | Scud | |
| 0 | 0 | Watersnipe Larva | |
| Sub Total: | 69 | 6 | 22 |
| Category 3 - Pollution Tolerant | 39 | 4 | Aquatic Worm |
| 2 | 1 | Blackfly Larva | |
| 11 | 2 | Leech | |
| 66 | 6 | Midge Larva (chironomid) | |
| 2 | 1 | Planarian | |
| 4 | 3 | Pouch Snail | |
| 0 | 0 | Truebug Adult | |
| 5 | 2 | Water Mite | |
| Sub Total: | 129 | 19 | 16 |
| Total: | 231 | 26 | 52 |