Early Development and Feeding Plasticity in An Invasive Population of Lake Trout

Session: Exploring Predator-prey Dynamics and Feeding Ecology in the Great Lakes (1)

J. Marsden, University of Vermont, Rubenstein School of Environment and Natural Resources, [email protected]
Lee Simard, University of Vermont, [email protected]
Robert Gresswell, U.S. Geological Survey, Northern Rocky Mountain Science Center, [email protected]
Megan Euclide, University of Vermont, [email protected]

Abstract

An invasive population of lake trout in Yellowstone Lake has grown exponentially, likely because the lake is a species-depauperate system without any major predators of lake trout early life stages. We hypothesized that, without a predation threat, lake trout free embryo feeding and growth in Yellowstone Lake may be greater than in their native range, leading to increased survival of age-0 individuals and the rapid population growth observed in Yellowstone Lake. We compared length, development, and feeding of free embryos in Yellowstone Lake with data from Lake Champlain, VT. The majority of free embryos (96%) in Yellowstone Lake were feeding compared to 81% in Lake Champlain. The average length of lake trout free embryos in Yellowstone Lake was significantly greater than free embryos in Lake Champlain at the same developmental stages. With an abundance of available food and no threat of predation, free embryos remained on the spawning site in Yellowstone Lake much later into the summer than in Lake Champlain, allowing them to achieve a greater maximum length before they left the site. This higher feeding and growth likely leads to high survival of lake trout free embryos in Yellowstone Lake, contributing to the population’s rapid growth.