1. Decline of the Savannah River Redeye Bass (Micropterus coosae) due to Introgressive Hybridization with Invasive Alabama Spotted Bass (Micropterus punctulatus henshalli )
Richard T. Bryan and Wayne S. Starnes
Max Bangs
August 10th, 2012

2. Invasive Species Anthropogenic Threatens Native Taxa Effects
Competition
Predation
Hybridization
Zanden et al. 2004

3. Hybridization Introgression Studies Erosion of genomes Extinction
Mammals (wolves and wildcats, Randi, 2008)
Birds (partridges, Randi, 2008; quail, Chazara et al., 2010)
Tree frogs (Klymus et al., 2010)
Irises (Arnold et al., 2010)
Ichthyofauna (suckers, Douglas and Douglas, 2010; black bass, Oswald, 2007)

4. Micropterus Endemic Eastern North America Widely introduced Hybridize
Four common species
Florida Bass (M. floridanus)
Northern Largemouth Bass (M. salmoides)
Spotted Bass (M. punctulatus)
Smallmouth Bass (M. dolomieu)
Four rare species
Shoal Bass (M. cataractae)
Guadalupe Bass (M. treculi)
Suwannee Bass (M. notius)
Redeye Bass (M. coosae)

5. Redeye Bass

6. M. coosae Altamaha/Ogeechee M. floridanus
M. salmoides
M. treculi
M. notius
M. coosae Mobile
M. punctulatus Mobile
M. cataractae Chattahoochee
M. coosae Chattahoochee
M. coosae Savannah
1.0
Bayesian Tree using
ND2 from Oswald, 2007
.98
1.0
1.0
1.0
1.0
1.0
1.0
.76
1.0
.69
1.0
1.0
1.0
Pictures © Richard T. Bryan and Wayne S. Starnes

7. Savannah River Reservoir System
Lake Jocassee
(+ Smallmouth Bass)
Lake Keowee
(+ Alabama Spotted Bass)
Lake Hartwell
Lake Russell
Picture from Dr. Kenneth Oswald

8. Purpose Examine hybridization over temporal and spatial scales
Future of “Bartram’s Bass” in these impoundments.

9. Collecting Angling/Electroshocking Fin Clip Ethanol Storage
15 sites (avg. 40 fish per site)
Unbiased sampling
Fin Clip
Ethanol Storage

10. Laboratory Methods DNA Extraction from Fin Clip PCR Amplify:
Using a Qiagen Kit
PCR Amplify:
mtDNA ND2 gene
scnDNA Calmodulin intron
scnDNA Actin intron
scnDNA ITS2 intron
Direct Sequencing PCR Products
ExoSAP cleanup
ABI sequencer

11. Analytical Methods Categories ‘Pure’ Hybrid Largemouth Bass (LMB)
Smallmouth Bass (SMB)
Redeye Bass (REB)
Alabama Spotted Bass (ASB)
Hybrid
Alabama Spotted x Redeye (ASB/REB)
Other hybrid
Chaing et al. 2006

12. 2004 Largemouth Bass relatively unaffected
20% - 40% in all lakes
No hybrids found
Smallmouth Bass only found in Lake Jocassee and no hybrids found
Redeye Bass and Alabama Spotted Bass
Hybrids in all four lakes
Redeye heavy impacted

13. ASB x REB
ASB, REB, and ASB/REB made up the majority of the lake composition (53% to 69%)
Composition within varied between lakes
REB ASB ASB/REB

14. ASB x REB Composition within these categories shifted over time REB
ASB/REB
REB ASB ASB/REB

15. Genotype Scoring REB, ASB, and ASB/REB
Individuals given a score between 0 and 6 based on the number of ASB nuclear alleles they possessed
0 = ‘pure’ REB
6 = ‘pure’ ASB

16. Time since Introduction
2004
2010
Jocassee
Hartwell
mtDNA
REB
ASB
Time since Introduction
Russell
Keowee

17. Largemouth Bass Jocassee Keowee Hartwell Russell 2004 20% 37% 47% 44%
Little change temporally
Four hybrids in 2010
Introgression absent
REB buffer?
Future hybridization possible
Jocassee
Keowee
Hartwell
Russell
2004
20%
37%
47%
44%
2010
15%
31%
42%
46%

18. Smallmouth Bass Lake Jocassee 12% to 11% Restricted Seven hybrids
Hybrids with ASB/REB
Introgression
Threat to REB refugia?

19. Why Is This Important “Bartram’s Bass” is being extirpated
Largemouth Bass facing a hybrid threat.
Will this have a greater effect?
© 2008 Pearson Education, Inc.

20. Acknowledgements
Dr. Joseph Quattro
Dr. Kenneth Oswald
SCDNR
Lab Mates

21. Questions