Long-term variation in the Wabash River ecosystem The Wabash River Workshop IUPUI Dec 13, 2013 Mark Pyron Center of Aquatic Biology and Fisheries Environmental Science

Background –Side scan sonar Long term fish assemblage –Size spectral analysis –Isotope analyses

Wabash River 2nd largest trib of Ohio River 85,000 km 2 watershed 764 km long

Upstream Wabash River: medium-sized river with gravel substrates

Inner bends have sandy beaches

Downstream: large river; some vegetated riparian buffer

and flat meanders

230 km 1. Fish data James Gammon Mark Pyron

Jim Gammon began project m sites Boat electrofishing

Electrofish 500 m Collect all fishes Measure, release Sampling Protocol:

Fish assemblage patterns Major gradient = river distance: substrate and habitat variation Species separate along gradients

Upstream: riffles, pools, gravel- cobble Blue sucker River redhorse

Shovelnose sturgeon Everywhere = Freshwater drum

Downstream: runs, sand-silt Flathead catfish Bigmouth buffalo

Grass carp

Asian carp

Sauger Longnose gar

GIS Approach to Analysis of Fish Assemblages Using Bathymetry, Water Velocity, Sediment and Woody Debris Mark Pyron, Reuben Goforth, Jayson Beugly, Scott Morlock, Moon Kim

Sample 1: June 2009 Acoustic Doppler Current Profiler Interfaced with Differential Global Positioning System receiver 10-km reach at Lafayette, Indiana

Three boats collect fishes: Ball State, Purdue, IDNR Left, Center, Right bank Individual fish assigned lat-long GPS coordinate

Majority of fishes along banks Blue sucker Carpsucker Freshwater drum

CCA 4 x 4 m

CCA 10 x 10 m

CCA 30 x 30 m

Summer 2012 Sidescan sonar map; most of Wabash River Collect fishes at four locations Predict assemblages for entire river

Highest abundances? Rank abundanceSpecies 21.2 %Silver Carp 16.1 %Gizzard Shad 12.1 %Freshwater Drum

CCA: species and environmental variables MEAN DEPTH Gravel

Long term fish assemblage –Size spectral analysis –Time lag ordination –Isotope analyses

Size spectral analysis: examine organisms by size Convert size-abundance matrix into size bins Regress abundances against size bins

Examine organisms by size Convert size-abundance matrix into size bins Regress abundances against size bins Steeper with exploitation Steep regression = inefficient ecological transfer

Spectral analysis Use only individuals > 162 mm SL (susceptible to boat electrofisher) Regime shift in 1990s?

steep regression = inefficient ecological transfer

Trophic Groups

Diet of fishes change? Pilot analysis Isotope analyses: 13C and 15N ratios Museum archives Detritivore = gizzard shad Omnivore = spotfin shiner Piscivore = spotted bass

One trophic level ~ 3 ppt d15N AlgaeMacrophytes

INHS archival fishes: Wabash River

Gizzard shad consume additional sources NANFA.ORG

Gizzard shad consume additional sources Shiner consume lower trophic sources NANFA.ORG

Individuals consume lower trophic levels in upstream locations

ISOTOPE RESULTS Diet of consumer fishes (planktivore / omnivore) in 1990s Different algae? Different nutrients? Impact of Asian carp?

Summary Switch in functional group dominanceSwitch in functional group dominance Omnivores + planktivores to benthivoresOmnivores + planktivores to benthivores Asian carp cause change in food web?Asian carp cause change in food web?