Movement of Sea Lamprey in the Lake Champlain Basin

Abstract

Sea lamprey ( Petromyzon marinus) are a nuisance aquatic species in the Great Lakes and Lake Champlain that have devastated native fish populations and hampered the restoration of sport fisheries. This study examined inter-basin movement of sea lamprey in Lake Champlain to identify tributaries that contribute parasitic-phase sea lamprey and provide information for prioritizing those tributaries for sea lamprey control. A total of 4,125 recently metamorphosed sea lamprey was captured in tributaries to Lake Champlain and marked using coded wire tags between the fall of 2001 and winter 2003. These sea lamprey migrated to the lake to prey on salmonids and other fishes and returned to tributaries to spawn about 12–18 months after migration. We recaptured 6 tagged sea lamprey from the lake from spring 2002 through winter 2004, and 35 from tributaries in spring 2003 and 2004. We noted no apparent trends in movement among basins. Sea lamprey were collected at distances up to 64 km from their natal tributaries. Tributary contributions of parasites were significantly different from expectations in the 2002 parasitic-phase cohort (χ 2 = 9.668, p < 0.011, 3 df), suggesting differential survival rates among out-migrating transformers from different tributaries. Estimates of the lake-wide out-migrating transformer population for the 2002 and 2003 parasitic-phase cohorts were 269,139 ± 55,610 (SD) and 111,807 ± 23,511 (SD). Results from this study suggest that sea lamprey movement is not inhibited by causeways dividing sub-basins, but movement among sub-basins is somewhat constrained. This indicates that management efforts to control sea lamprey should continue to treat the lake as a single system.