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?