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

Thompson River Decatur City

Fish Session #1330

Sample Date
9/23/2011
Timeframe
1130-1225  
Reach Size
1161 ft
Method
Standard Wadeable
Sample Quality
Good
Last Update
2/25/2015 8:31:32 AM

Fish Health

# DELTs
1
# Non-DELTs
0

Equipment

Backpack Shockers
0
Blocknets
2
Barge Shocker
True
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
43
Warm Water
Fair
Session Comments

Wide channel and swift current in some areas made sampling a bit difficult.

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
Channel Catfish
Latin: Ictalurus punctatus
Family: Ictaluridae
Tolerance: Intermediate
Trophic: Top Carnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
483
Red Shiner
Latin: Cyprinella lutrensis
Family: Leuciscidae
Tolerance: Tolerant
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
393
Suckermouth Minnow
Latin: Phenacobius mirabilis
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: True
Is Hybrid: False
99
Sand Shiner
Latin: Miniellus stramineus
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Insectivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
34
Stonecat
Latin: Noturus flavus
Family: Ictaluridae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
16
Green Sunfish
Latin: Lepomis cyanellus
Family: Centrarchidae
Tolerance: Tolerant
Trophic: Generalist
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
14
Bluntnose Minnow
Latin: Pimephales notatus
Family: Leuciscidae
Tolerance: Tolerant
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
13
Bullhead Minnow
Latin: Pimephales vigilax
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
12
Bigmouth Shiner
Latin: Ericymba dorsalis
Family: Leuciscidae
Tolerance: Tolerant
Trophic: Insectivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
9
Flathead Catfish
Latin: Pylodictis olivaris
Family: Ictaluridae
Tolerance: Intermediate
Trophic: Top Carnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
9
Fathead Minnow
Latin: Pimephales promelas
Family: Leuciscidae
Tolerance: Tolerant
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
8
Shoal Chub
Latin: Macrhybopsis hyostoma
Family: Leuciscidae
Tolerance: Intermediate
Trophic: Benthic Invertivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
5
River Carpsucker
Latin: Carpiodes carpio
Family: Catostomidae
Tolerance: Intermediate
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
5
Quillback Carpsucker
Latin: Carpiodes cyprinus
Family: Catostomidae
Tolerance: Intermediate
Trophic: Omnivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
1
Largemouth Bass
Latin: Micropterus nigricans
Family: Centrarchidae
Tolerance: Intermediate
Trophic: Top Carnivore-LMB Exclusion
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
1

FIBI Calculation Factors

Factor Value
Drainage area (mi2) 601.7000
Log(DA) 2.7794
Total Fish 1102
Fish per 500 ft 475
Total Species 15
# Excluded Taxa 0
# Exotic Species 0
# LMB-BG 1
Calculation Last Updated 10/10/2025 8:08:05 AM

Fish Index of Biotic Integrity

Metric Name Value Score
Native Species 14 6.09
Sucker Species 2 4
Sensitive Species 0 0
Benthic Invertivore Species 3 4.29
Top 3 Abundance Percentage 88.48 1.79
Benthic Invertivore Percentage 10.89 1.79
Omnivore Percentage 39.2 5.39
Top Carnivore Percentage 44.65 10
Lithophilous Spawner Percentage 8.98 2.99
Tolerance Index 6.98 4.79
Adjusted Catch per Unit Effort 57.28 5.73
DELT Percentage Adjustment 0.09 0

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 Candidate Reference Site. Further study is required to determine if this site represents natural stream qualities that are least disturbed by human activities within the watershed.

EcoRegion Comparison

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

Loess Flats and Till Plains

This site is in the Loess Flats and Till Plains ecoregion.

Ecoregion Map
Max 63
75th Percentile 47
Median 41
25th Percentile 35
Min 16
This Session's Score 43
Total Reference Site Samples 49
Mean 40.8
Standard Deviation 12.08