**The title, authors, and abstract for this completion report are provided below. For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**
Distribution and factors affecting survival of sea lamprey eggs in and out of nests
Stephen Smith2, and J. Ellen Marsden2
2Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT 05405
Sea lamprey (Petromyzon marinus) is a nuisance species in the Great Lakes and Lake Champlain that has inhibited recovery of salmonid populations. In an effort to optimize control efforts, recent research has focused on creating population models to evaluate various control scenarios. Accurate population parameters, such as fecundity and egg survival rates, are an important component of these models. The purpose of this research was to provide data on these information gaps in our understanding of lamprey life history in Lake Champlain. Fecundity of 29 sea lamprey was determined to be 67,642 ± 6,578 (95% CI). Wet weight of the female was a more significant predictor of fecundity than total length or nine other morphometrics, including GSI. Field trials using exclosure boxes (covered and uncovered) set into spawning gravel and silt showed that egg loss was significantly different between spawning gravel (65.6% ± 7.4%) and silt (93.4% ± 5.3%; p < 0.0001) and was not impacted by the presence of a cover on either substrate (p < 0.143). In laboratory studies of predation, crayfish, logperch, creek chub, and white sucker were allowed 18 hours to feed on sea lamprey eggs on five substrates: no substrate, silt, sand, spawning gravel, and cobble. Substrate type had no effect on the numbers of eggs consumed by predators, but different predators consumed significantly different numbers of eggs (F-ratio = 11.12, df = 3, p <0.0001). Crayfish consumed 74% of available eggs, creek chub consumed 47.2%, white sucker consumed 8.7%, and logperch consumed 3.0% on average. Survival of eggs to stage 12 in an experimental hatching system was significantly different among substrates (F-ratio = 27.74, df = 2, p< 0.0001). Egg survival on silt (69.2%) and sand (50.8%) was significantly higher than survival on spawning gravel (19.1%). These results suggest that initial egg mortality is high because most spawned eggs (90%) are not deposited in the nest and predation on eggs not buried in a nest is likely high. Stream substrate alone does not affect hatching success, and egg mortality may be highly variable depending on stream conditions. However, under certain stream conditions, such as low flow, eggs outside of the nest may have relatively high survival.
**Note: This project was not funded through the Sea Lamprey Research Program.**