Iowa DNR
BioNet
River & Stream Biological Monitoring
Fish and Benthic Macroinvertebrate Surveys
Physical Habitat Assessments

Silver Creek Dewitt

Fish Session #33

Sample Date
7/22/1998
Timeframe
0920-1050  
Reach Size
781 ft
Method
Standard Wadeable
Sample Quality
Good
Last Update
2/27/2025 12:48:12 PM

Fish Health

# DELTs
12
# Non-DELTs
0

Equipment

Backpack Shockers
2
Blocknets
2
Property Access Notice

This site is on privately-owned land. The DNR obtains permission from the landowner(s) prior to conducting any sampling surveys.

FIBI Score
40
Warm Water
Fair
Session Comments

OVERCAST SKY, RAINING ON AND OFF DURING SAMPLING TIME. AIR TEMPERATURE WAS APPROX. 80 F. FLOW LEVEL WAS NEAR NORMAL BASE FLOW OR SLIGHTLY HIGHER THAN NORMAL. TURBIDITY LEVEL OF WATER WAS MODERATELY HIGH AND THE STREAM BOTTOM WAS VISIBLE TO APPROX. 1.5 FT. FISH SPECIMENS WERE KEPT.

Collected Fish

Identity verification status for this species
Size Class: Typically only collected for sportfish
Taxa excluded from species count metrics.
Click on species name for more information about that species
Species Catch
White Sucker
Latin: Catostomus commersonii
Family: Catostomidae
Tolerance: Intermediate
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
62
Bluntnose Minnow
Latin: Pimephales notatus
Family: Leuciscidae
Tolerance: Tolerant
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
35
Common Carp
Latin: Cyprinus carpio
Family: Cyprinidae
Tolerance: Tolerant
Trophic: Omnivore
Is Exotic: True
Is LithoSpawner: False
Is Hybrid: False
28
Longnose Dace
Latin: Rhinichthys cataractae
Family: Leuciscidae
Tolerance: Sensitive
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
19
Creek Chub
Latin: Semotilus atromaculatus
Family: Leuciscidae
Tolerance: Tolerant
Trophic: Generalist
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
19
Fantail Darter
Latin: Etheostoma flabellare
Family: Percidae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
17
Western Blacknose Dace
Latin: Rhinichthys obtusus
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Insectivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
16
Central Stoneroller
Latin: Campostoma anomalum
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Herbivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
12
Mississippi Silvery Minnow
Latin: Hybognathus nuchalis
Family: Leuciscidae
Tolerance: Sensitive
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
11
Green Sunfish
Latin: Lepomis cyanellus
Family: Centrarchidae
Tolerance: Tolerant
Trophic: Generalist
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
8
Emerald Shiner
Latin: Notropis atherinoides
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Insectivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
4
Bigmouth Shiner
Latin: Ericymba dorsalis
Family: Leuciscidae
Tolerance: Tolerant
Trophic: Insectivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
4
Largemouth Bass
Latin: Micropterus nigricans
Family: Centrarchidae
Tolerance: Intermediate
Trophic: Top Carnivore-LMB Exclusion
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
4
Johnny Darter
Latin: Etheostoma nigrum
Family: Percidae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
3
Brassy Minnow
Latin: Hybognathus hankinsoni
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Herbivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
2
Common Shiner
Latin: Luxilus cornutus
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Insectivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
2
Channel Catfish
Latin: Ictalurus punctatus
Family: Ictaluridae
Tolerance: Intermediate
Trophic: Top Carnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
2
Smallmouth Bass
Latin: Micropterus dolomieu
Family: Centrarchidae
Tolerance: Sensitive
Trophic: Top Carnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
2
Spotfin Shiner
Latin: Cyprinella spiloptera
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Insectivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
1
Suckermouth Minnow
Latin: Phenacobius mirabilis
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: True
Is Hybrid: False
1
Fathead Minnow
Latin: Pimephales promelas
Family: Leuciscidae
Tolerance: Tolerant
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
1
Quillback Carpsucker
Latin: Carpiodes cyprinus
Family: Catostomidae
Tolerance: Intermediate
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
1
Shorthead Redhorse
Latin: Moxostoma macrolepidotum
Family: Catostomidae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: True
Is Hybrid: False
1
Black Bullhead
Latin: Ameiurus melas
Family: Ictaluridae
Tolerance: Tolerant
Trophic: Generalist
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
1
Yellow Bullhead
Latin: Ameiurus natalis
Family: Ictaluridae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
1
Stonecat
Latin: Noturus flavus
Family: Ictaluridae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
1

FIBI Calculation Factors

Factor Value
Drainage area (mi2) 35.9230
Log(DA) 1.5554
Total Fish 258
Fish per 500 ft 165
Total Species 26
# Excluded Taxa 0
# Exotic Species 1
# LMB-BG 1
Calculation Last Updated 2/27/2025 12:48:13 PM

Fish Index of Biotic Integrity

Metric Name Value Score
Native Species 24 9.26
Sucker Species 3 5.92
Sensitive Species 3 3.38
Benthic Invertivore Species 7 7.5
Top 3 Abundance Percentage 48.45 8.5
Benthic Invertivore Percentage 16.67 4.5
Omnivore Percentage 53.49 3.5
Top Carnivore Percentage 1.55 4.52
Lithophilous Spawner Percentage 0.78 0.42
Tolerance Index 6.24 5.97
Adjusted Catch per Unit Effort 20.74 2.07
DELT Percentage Adjustment 4.65 -10

FIBI Score Explained

Sites that score between 26 - 50 are considered fair. Fish abundance ranges from lower than average to very abundant. If fish are abundant, tolerant species are usually dominant. Native fish species usually equal ten or more species. The three most abundant species typically comprise two-thirds or more of the total number of fish. One or more sensitive species, long-lived fish species or benthic habitat specialists such as suckers (Catostomidae) are present. Top carnivore species are often, but not always present in low abundance. Species that are able to utilize a wide range of food items including plant, animal and detritus are usually more common than specialized feeders, such as benthic invertivore fish. Species that require silt-free, rock substrate for spawning or feeding are typically rare or absent. Fish condition is usually good; however, elevated levels of fish exhibiting external anomalies associated with disease or stress are not unusual.

This location has been classified as a Reference Site. Reference sites represent natural stream qualities that are least disturbed by human activities within the watershed. These sites are then grouped by ecoregion to establish a benchmark against which other streams in the same ecoregion are compared.

EcoRegion Comparison

Scores for a sampling session are compared against reference sites within the same ecoregion:

Rolling Loess Prairies

This site is in the Rolling Loess Prairies ecoregion.

Ecoregion Map
Max 83
75th Percentile 59
Median 48
25th Percentile 38
Min 10
This Session's Score 40
Total Reference Site Samples 105
Mean 49.02
Standard Deviation 14.97