The Nature Conservancy’s Emiquon Preserve Fish and Aquatic Vegetation Monitoring 2024 Field Report

Holda, Toby J.; Solomon, Levi E.; Lamer, James T.

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https://hdl.handle.net/2142/132955 Copy

Description

Title

The Nature Conservancy’s Emiquon Preserve Fish and Aquatic Vegetation Monitoring 2024 Field Report

Author(s)

• Holda, Toby J.
• Solomon, Levi E.
• Lamer, James T.

Issue Date

2026-03-06

Keyword(s)

• Restoration
• Resource Management
• Fish communities
• Vegetation
• Monitoring
• Key Ecological Attributes
• Biomass
• Backwater Lakes
• Illinois River Valley
• The Nature Conservancy
• Illinois Department of Natural Resources (IDNR)
• Illinois River Biological Station
• Submerged aquatic vegetation (SAV)
• Fish assemblages
• Emiquon Science Advisory Council
• Conservation
• Upper Mississippi River Restoration
• Long Term Resource Monitoring (LTRM)
• Fisheries

Date of Ingest

2026-03-09T11:53:08-05:00

Geographic Coverage

Illinois

Abstract

Since 2007, the Emiquon Preserve (Emiquon) has been monitored using Key Ecological Attributes (KEA) to determine the success of restoration on the vegetation and fish communities. The KEA’s were developed to reflect a high-functioning, balanced ecosystem at its upper limits. Vegetation Monitoring: SAV communities were dominated by native species from 2008 through 2023, but in 2024 the community was predominantly invasive (mostly Eurasian milfoil Myriophyllum spicatum), based on both box (34% native) and rake (47% native) surveys from 2024. SAV densities in 2024 were higher than compared to 2021-2023 based on box sampling. However, according to rake sampling estimates, our 2024 estimate was still about as low as our 2023 estimate, both of which were about 10% of densities observed during 2010-2015. Water transparency has remained low since 2020 (< 20 cm mean Secchi readings) and the KEA for Secchi depth has not been met. The community has shifted from more sensitive species to those that are more robust in the face of more turbid water conditions. Specifically, the community has shifted from coontail (Ceratophyllum desmersum), Canadian waterweed (Elodea canadensis), and naiads (Najas spp.) to milfoils (Myriophyllum spp.) and American lotus (Nelumbo lutea) with patches of naiads, coontail, or longleaf pondweed (Potamogeton nodosus) interspersed. Fisheries Monitoring As in all previous years, the Emiquon Preserve’s 2024 fish community continues to be dominated by native fish species in number (99.4%) and biomass (78.5%). In 2024, the community was dominated by Gizzard Shad (Dorosoma cepedianum), Yellow Bass (Morone mississippiensis), Bluegill (Lepomis macrochirus), and Black Crappie (Pomoxis nigromaculatus) by number (Fig. 14). By biomass, the 2024 fish community sampled by our monitoring gears was primarily Common Carp (Cyprinus carpio), Bowfin (Amia calva), and White Crappie (Pomoxis annularis), with Yellow Bass, Black Crappie, Channel Catfish (Ictalurus punctatus), Gizzard Shad, Bluegill, and Largemouth Bass (Micropterus nigricans) contributing noticeable biomass as well. It is worth noting that Yellow Bass collections went from 0 in 2015 and 2 in 2017 to 3,310 in 2021 and are now at 1,961 in 2024 (Fig. 23). As a small piscivore, this rapid population increase may impact other piscivore populations at Emiquon. Overwinter under-ice oxygen levels, when measured, have met the KEA requirement (i.e., between 7 and 10 ppm and between 75% and 110% saturation).

Publisher

Illinois Natural History Survey

Series/Report Name or Number

INHS Technical Report: 2026 (05)

Type of Resource

text

Genre of Resource

technical report

Language

eng

Sponsor(s)/Grant Number(s)

The Nature Conservancy C12-52

Copyright and License Information

This document is a product of the Illinois Natural History Survey, and has been made available by the Illinois Natural History Survey and the University Library, University of Illinois at Urbana-Champaign. It is intended solely for noncommercial research and educational use, and proper attribution is required.

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