Abstract
The origin of populations of the landlocked Sea Lamprey Petromyzon marinus in Lakes Champlain and Ontario, whether by artificial canals or by natural colonization following the last ice age, is controversial, in part because the related history and ecology had been poorly documented. This situation favored a native classification for the populations in both lakes based mainly on genetics. A native classification for the Lake Champlain population was predicated on either of two erroneous dates of first record, 1841 and 1894, whereas the correct date, 1929, was much more recent and strongly supports a nonnative classification. The detection of the Sea Lamprey in Lake Champlain occurred shortly after the opening in 1916 of the Champlain Barge Canal, which opened the upper Hudson River to fish passage. The case for a native Lake Ontario population did not account for a watershed breach in 1863 between the Susquehanna River, where the Sea Lamprey had been common, and the Lake Ontario drainage. Shortly after this canal-related connection was made, Sea Lamprey populations became abundant, nearly simultaneously, in four locations in the Lake Ontario drainage, suggesting this breach was the entry point for the founding population. The genetic distances between the landlocked populations and the Atlantic Ocean population appear to have been caused by recent bottlenecks rather than long-term residence; a recent genetic bottleneck was detected in the Lake Ontario population. Native classifications rested, in part, on extraordinary ecological scenarios, whereas nonnative classifications are consistent with experience in the upper Great Lakes and with well-known vectors of range expansion (canals, dam openings, watershed breaches). These findings in aggregate favor a nonnative classification of the Sea Lamprey in both lakes.
Received November 7, 2013; accepted December 16, 2013
ACKNOWLEDGMENTS
I especially thank Jill Wingfield for providing a critical review and reworking the figures, and two peer reviewers: Douglas Carlson and one anonymous. I also thank the following individuals for their help in producing this paper: Jean Adams, Daniel Bishop, Douglas Carlson, Prosanta Chakrabarty, Janet Eshenroder, Paige Etter, Neave Fraser, Thomas Grasso, Brad Hammers, Andre Kitzman, Charles Krueger, Randy Jackson, Rich Langdon, Bridget Lavelle, Nancy Leonard, Scott Miehls, Fraser Neave, Anthony Opalka, Amelia O’Shea, Matt Paul, Scott Prindle, Bill Schoch, Sarah Seegert, C. Lavett Smith, Gerry Smith, Wendy Stott, Paul Sullivan, Daniel Ward, Fred Wehner (Tug 44), Craig Williams, Bradley Young, and Emily Zollweg. This project also benefited greatly from the Canal Society of New York State, the Erie Canal Museum, the Old Fort House Museum of Fort Edward in New York, Sim's Museum at Camillus State Canal Park, and the William L. Clements Library at the University of Michigan.