Bioenergetics Model and Foraging Hypothesis for Sea Lamprey (Petromyzon marinus)

Abstract

A bioenergetics model for growth of lamprey during the parasitic phase was used to estimate food consumption by lampreys and the impact of lamprey feeding on host fishes. Estimates are evaluated by application to several Great Lakes case histories. Temperature and size-dependence of feeding and respiration were sufficient to account for growth dynamics. The model demonstrates that distribution of host fishes, by determining the thermal history of the lamprey, has important effects on lamprey life history and host mortality. Modeled lamprey growth and feeding rates, relative to size of the host, predict a strongly seasonal host mortality rate peaking in autumn. The predicted mortality pattern corresponds with that of independently derived data. Principles of optimal foraging theory applied to lamprey yield a hypothesis that predicts highest wounding and scarring frequencies at intermediate lamprey: host abundance ratios. A second component of the hypothesis predicts seasonal changes in these frequencies as lamprey size increases. Growth rates of lamprey and their host species plus wounding and scarring frequencies are more sensitive indicators of changing abundance ratios and lamprey effects than population changes resulting from predation by lamprey.Key words: sea lamprey, Petromyzon marinus; model, bioenergetics, growth, consumption, fish mortality, Great Lakes