Module 4 Stream Invertebrate Survey Interpretation
TWINS RIVER | Survey ID: 253
A) Abundance and density
ABUNDANCE: 27 / NUMBER OF SAMPLES: (3 *.09) = DENSITY: 100.00
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) = 21
2 x (# of category 2) = 22
(# of category 3) = 8
= 51
EPT INDEX
Good
Acceptable
Marginal
Poor
greater than 8
5 - 8
2 - 5
0 - 1
Total number of EPT taxa from Column C = 2
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
20 / total
27 =
0.74
D) DIVERSITY ASSESSMENT
TOTAL NUMBER OF TAXA: 2
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 17 / 27 = 0.6296
SITE ASSESMENT RATING
Good
Acceptable
Marginal
Poor
4
3
2
1
Pollution Tolerance Index: 4
EPT Index: 2
EPT to Total Ratio: 3
Predominant Taxon Ratio: 2
Total: 2.75
| POLLUTION TOLERANT INDEX | |||
|---|---|---|---|
| Good | Acceptable | Marginal | Poor |
| greater than 22 | 22 - 17 | 16 - 11 | less than 11 |
3 x (# of category 1) = 21
2 x (# of category 2) = 22
(# of category 3) = 8
= 51
2 x (# of category 2) = 22
(# of category 3) = 8
= 51
| 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
20 / total
27 =
0.74
| 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: 2
EPT to Total Ratio: 3
Predominant Taxon Ratio: 2
Total: 2.75
EPT Index: 2
EPT to Total Ratio: 3
Predominant Taxon Ratio: 2
Total: 2.75
Field Data as Collected
Polution Tolerance |
Number Counted | Number of Taxa | Common Name |
| Category 1 - Polution Intolerant | 0 | 0 | Caddisfly |
| 0 | 0 | Dobsonfly | |
| 0 | 0 | Gilled Snail | |
| 17 | 2 | Mayfly | |
| 0 | 0 | Riffle Beetle | |
| 3 | 0 | Stonefly | |
| 0 | 0 | Water Penny | |
| Sub Total: | 20 | 2 | 7 |
| Category 2 - Somewhat Pollution Tolerant | 0 | 0 | Alderfly larva |
| 0 | 0 | Aquatic Beetle | |
| 0 | 0 | Aquatic Sowbug | |
| 0 | 0 | Clam, Mussel | |
| 0 | 0 | Cranefly Larva | |
| 0 | 0 | Crayfish | |
| 0 | 0 | Damselfy Larva | |
| 0 | 0 | Dragonfly Larva | |
| 0 | 0 | Fishfly Larva | |
| 0 | 0 | Scud | |
| 0 | 0 | Watersnipe Larva | |
| Sub Total: | 0 | 0 | 11 |
| Category 3 - Pollution Tolerant | 0 | 0 | Aquatic Worm |
| 0 | 0 | Blackfly Larva | |
| 0 | 0 | Leech | |
| 0 | 0 | Midge Larva (chironomid) | |
| 0 | 0 | Planarian | |
| 0 | 0 | Pouch Snail | |
| 0 | 0 | Truebug Adult | |
| 7 | 0 | Water Mite | |
| Sub Total: | 7 | 0 | 8 |
| Total: | 27 | 2 | 26 |