Long-term variation in the Wabash River ecosystem

The Wabash River WorkshopIUPUI Dec 13, 2013

Mark PyronCenter of Aquatic Biology and FisheriesEnvironmental Science

• Background – Side scan sonar

• Long term fish assemblage– Size spectral analysis– Isotope analyses

Wabash River•2nd largest trib of Ohio River

•85,000 km2 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

Carroll

Tippecanoe

Warren

Fountain

Parke

Verm

illio

n

Vigo

Sullivan

Terre Haute

Clinton

10 km

Indiana

N

1. Fish data

James Gammon 1974-98Mark Pyron 2000-8

Jim Gammon began project 1974-98

•500-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-cobbleBlue sucker

Riverredhorse

Shovelnose sturgeon

Everywhere =Freshwaterdrum

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 suckerCarpsuckerFreshwater drum

0.20.0-0.2

0.00

-0.08

-0.16

CCA1

CC

A2

Current velocity

Substrate

Water depth

Latitude

Longitude

4 x 4 m resolution

20-2

3

0

-3

CCA1

CC

A2

EmShin

Gar

Walleye

Mooneye

GizShadChanCat Buffalo

BlSucker

GrCarp

Carp

SilvCarp

CarpSu

Redhorse

FreshDrum

Sturgeon

CCA 4 x 4 m

CCA 10 x 10 m

0.20.10.0-0.1

0.2

0.1

0.0

-0.1

CCA1

CC

A2

Woody debris

Current velocity

Substrate

Water depth

Latitude

Longitude

resolution10 x 10 m

420-2

2

1

0

-1

CCA1

CC

A2

EmShiner

Gar

Walleye

Mooneye

GizShad

ChanCat

Buffalo

BlSucker GrCarp

Carp

SilvCarp

Carpsuck

Redhorse

FreshDrum

ShovSturgeon

CCA 30 x 30 m

0.10.0-0.1-0.2

0.1

0.0

-0.1

CCA1

CC

A2

Woody debris

Current velocity

Substrate

Water depth

Latitude

Longitude

30 x 30 m resolution

20-2

2

0

-2

CCA1

CC

A2

EmShin

Gar

Walleye

Mooneye

GizShad

ChanCat

Buffalo

BlSucker

GrCarp

Carp SilvCarp

Carpsucker

Redhorse

FreshDrum

Sturgeon

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

Highest abundances?

Rank abundance Species

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?

1974-94

1994-1999

1999-2008

steep regression = inefficient ecological transfer

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

1970 1975 1980 1985 1990 1995 2000 2005 2010

Size

-Spe

ctra

Slop

eSize spectra slope:

Proxy for ecological (transfer) efficiency

1974-2008 Trophic Groups

Diet of fishes change?Pilot analysis

• Isotope analyses: 13C and 15N ratiosMuseum archives 1960-2008

Detritivore = gizzard shad

Omnivore = spotfin shiner

Piscivore = spotted bass

One trophic level ~ 3 ppt d15N

http://sofia.usgs.gov

Algae Macrophytes

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?

SummarySummary

• 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?