Fish Assemblages of the Wabash River Mark Pyron

Wabash River Fishes 1.Large river 2.High diversity 3.History of human impact 4.Fish assemblages respond to... 5.What are our goals?

Wabash River: a large river & significant natural ecosystem Longest free-flowing river east of Mississippi River 772 km rivertrek.org

Wabash River varies from narrow smaller upstream...

to downstream sandy beaches on insides of bends...

to vegetated riparian buffers.

Wabash River Fishes 1.Large river 2.High diversity 3.History of human impact 4.Fish assemblages respond to... 5.What next?

High fish diversity > 100 species

High fish diversity River carpsucker Freshwater drum Gizzard shad fishbase.org

High mollusk diversity 30+ mussels (18 extinct) > 9 gastropods inhs.illinois.edu

Wabash River Fishes 1.Large river 2.High diversity 3.History of human impact 4.Fish assemblages respond to... 5.What next?

James Gammon Depauw U Evaluated fish communities as biological indicators 1967 – 1998 Middle Section of Wabash River PSI (Duke) + Eli Lilly funded

Gammon showed: Fish assemblage quality decreased with impacts = agriculture + point source Poor fish assemblages 1967 – 1984 Improved point source treatment

Historic causes of degradation Pollution – Industrial point source – Municipal waste – Agricultural practices – Reservoir releases

Legislative Improvements Clean water act = decrease industrial pollution Agricultural programs = reduction in silt loss, nutrient loss Combined sewage overflows = improving

Wabash River Fishes 1.Large river 2.High diversity 3.History of human impact 4.Fish assemblages respond to... 5.What next?

Gammon Long term Wabash River Fishes:

Index of Biotic Integrity

Discharge at Montezuma

Four large floods at Montezuma

Were there patterns with floods and fish abundances? No simple patterns with flood timing, duration, frequency, rise rate;

Were there patterns with floods and fish abundances? No simple patterns with flood timing, duration, frequency, rise rate; Patterns with other hydrology variables = 90-day max, low pulse number

Species richness higher with gravel substrate and depth variation

Fish assemblages respond to... Point source pollution Disturbance = floods, droughts Habitat quality

Current issues Nutrient release – Sewage treatment plants – Agriculture toxics.usfs.gov

Current issues Hydrologic alterations – Reservoir release does not mimic natural flow regime – Agriculture: fields drain rapidly, causing fluctuation in rivers flickr.com

Current issues Hydrologic alterations – Majority of streams – Increased minimum flows, decreased maximum flows, increased fall rates, decreased high pulse count, increased zero flow days

Current issues Riparian zone quality – Degraded with erosion Floodplain connections – Downstream reaches – Off-channel habitats connected with flooding – Fishes, plants – Soil improvement wesselmannaturesociety.org

Current issues Invasive species – Common carp – Silver and bighead carp – Grass carp – Zebra mussels – Others?

Wabash River Fishes 1.Large river 2.High diversity 3.History of human impact 4.Fish assemblages respond to... 5.What next?

Collaborative restoration projects BMPs across watershed

BMPs Successful at small scales High cost at scale of entire watersheds streams.osu.edu

Collaborative restoration projects BMPs across watershed Rehabilitate off-channel habitat

Off-channel habitat can be productive for fishes – Degraded from siltation – Isolation from main channel Reconnect to main channel by removing barrier or adjusting hydrograph nishurs.blogspot.com

Collaborative restoration projects BMPs across watershed Rehabilitate off-channel habitat Reconnect floodplains

Significant plant, macroinvertebrate, and fish production sites Remove levees Modify hydrograph / dam release regime stacey.peak-media.co.uk

Collaborative restoration projects BMPs across watershed Rehabilitate off-channel habitat Reconnect floodplains Dam release modification – Successful elsewhere – Before / after details?

Dam release modification Predicted to improve ecosystem health > 20 successful projects in US – Green River, Kentucky – Bill Williams River, Arizona – Savannah River, Georgia – Tallapoosa River, Alabama flickr.com

Best strategy for Wabash River: combination of projects Increase BMPs Dam release modification Gravel supplements Reconnect off-channel habitat Riparian improvements Monitor for results or modify activities

Can we create new collaborative Wabash River projects?