A population genomics test of Niagara Falls’ effectiveness as a barrier to fish dispersal

Session: 02b. - Status and Management of Invasive Carps in the Great Lakes

Nathan Lujan, University of Toronto Scarborough, [email protected]
Jason Weir, University of Toronto Scarborough, [email protected]
Brice Noonan, University of Mississippi, Department of Biology, [email protected]
Nathan Lovejoy, University of Toronto Scarborough, [email protected]
Nicholas Mandrak, Biological Sciences, University of Toronto Scarborough, [email protected]

Abstract

As a choke point and presumed barrier to fish dispersal in the lower Great Lakes, the Niagara River and Falls are of interest to natural resource managers as potential control points to limit invasive fish dispersal throughout the Great Lakes. If Niagara Falls is a natural barrier to fish movement, artificial control technologies need only be installed in the Welland Shipping Canal, which parallels the Niagara River. We tested Niagara Falls’ historical importance as a barrier to fish movement by using genome-wide SNPs to estimate genetic structure and gene flow within populations of seven native fish species spanning habitats above and below the falls. Our three-enzyme RADseq pipeline yielded between 474 and 2,770 SNPs for each of the seven species. F-statistics and PCoAs of genomic diversity yielded no evidence of spatial structure in Rock Bass, White Sucker, Largemouth Bass and Shorthead Redhorse, and weak evidence of spatial structure in Brown Bullhead, Greater Redhorse, and Yellow Perch. Simulations based on the site frequency spectrum failed to differentiate between models with vs. without gene flow for any species. We conclude that historical demographic processes related to post-glacial colonization obscure the historical role of Niagara Falls as a barrier to gene flow. 

1. Keyword
fish

2. Keyword
Great Lakes basin

3. Keyword
genetics

4. Additional Keyword
barrier

5. Additional Keyword
fish movement