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

West Fork Unnamed Tributary Arbor Lake Grinnell

Fish Session #573

Sample Date
10/10/2003
Timeframe
1040-1115  
Reach Size
518 ft
Method
Standard Wadeable
Sample Quality
Good
Last Update
5/3/2019 9:15:29 AM

Fish Health

# DELTs
0
# Non-DELTs
0

Equipment

Backpack Shockers
1
Blocknets
1
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
37
Warm Water
Fair
Session Comments

No comments recorded.

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
Bluegill
Latin: Lepomis macrochirus
Family: Centrarchidae
Tolerance: Intermediate
Trophic: Insectivore
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
107
Largemouth Bass
Latin: Micropterus nigricans
Family: Centrarchidae
Tolerance: Intermediate
Trophic: Top Carnivore-LMB Exclusion
Is Exotic: False
Is LithoSpawner: False
Is Hybrid: False
48
Green Sunfish
Latin: Lepomis cyanellus
Family: Centrarchidae
Tolerance: Tolerant
Trophic: Generalist
Is Exotic: False
Is LithoSpawner: False
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

FIBI Calculation Factors

Factor Value
Drainage area (mi2) 0.7300
Log(DA) 0.0001
Total Fish 157
Fish per 500 ft 152
Total Species 4
# Excluded Taxa 0
# Exotic Species 0
# LMB-BG 2
Calculation Last Updated 2/7/2025 2:34:37 PM

Fish Index of Biotic Integrity

Metric Name Value Score
Native Species 2 10
Sucker Species 0 0
Sensitive Species 0 0
Benthic Invertivore Species 0 0
Top 3 Abundance Percentage 99.36 10
Benthic Invertivore Percentage 0 0
Omnivore Percentage 0.64 10
Top Carnivore Percentage 0 0
Lithophilous Spawner Percentage 0 0
Tolerance Index 5.06 7.84
Adjusted Catch per Unit Effort 29.92 2.99
DELT Percentage Adjustment 0 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 survey site. Survey sites are compared to reference sites within the same ecoregion. A reference site represents natural stream qualities that are least disturbed by human activities within the watershed. Reference sites are grouped by ecoregion to establish a benchmark against which these survey streams 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 37
Total Reference Site Samples 105
Mean 49.02
Standard Deviation 14.97