The evolution of sea lamprey control in the St. Marys River: 1997–2019

Abstract

Abstract The St. Marys River was historically the single largest sea lamprey (Petromyzon marinus) producer in the Great Lakes. Rehabilitation of the once thriving Lake Huron fishery that had collapsed due to overfishing and habitat degradation was significantly inhibited by this uncontrolled source of sea lamprey. In 1997, the Great Lakes Fishery Commission implemented an integrated control strategy that incorporated lampricide control (granular Bayluscide spot treatments), sterile male release technique (SMRT), and enhanced trapping during the spawning migration. A decrease in the abundance of juvenile sea lamprey in the St. Marys River and a decline in lake trout wounding rates in Lake Huron following large-scale granular Bayluscide treatments in 1998, 1999, 2010 and 2011 indicated that lampricide control was most effective in controlling larval sea lamprey abundance in the river. The effects from the SMRT and adult trapping, however, could not be fully determined. Uncertainty in the efficacy of these alternative control techniques and in stock-recruitment relationships, ultimately led to the termination of the integrated control strategy. Since 2012, sea lamprey in the St. Marys River have been controlled exclusively with granular Bayluscide to treat areas with high densities of larvae. An adaptive management approach that considers the best available data has been incorporated to monitor and evaluate the effectiveness of ongoing control strategies. The evolution of sea lamprey control in the St. Marys River has resulted in a 90% reduction in sea lamprey from the river and contributed to recovery of the Lake Huron fish community.