Investigating the Ecological Impacts of Anadromous Alewife Restoration in New EnglandEPA Grant Number: FP916341
Title: Investigating the Ecological Impacts of Anadromous Alewife Restoration in New England
Investigators: Palkovacs, Eric P.
Institution: Yale University
EPA Project Officer: Michaud, Jayne
Project Period: January 1, 2004 through December 31, 2006
Project Amount: $93,504
RFA: STAR Graduate Fellowships (2004) RFA Text | Recipients Lists
Research Category: Academic Fellowships , Aquatic Ecosystems , Fellowship - Aquatic Ecology and Ecosystems
The restoration of anadromous alewife (Alosa pseudoharengus) runs via dam removal and fish ladder construction means that these fish again will have access to inland waters from which they were excluded and that migratory and landlocked alewife populations will be brought into contact with each other. This study focuses on the ecological implications of restoring anadromous runs to lakes that have been without alewives as a result of downstream dams, as well as the ecological and evolutionary implications of restoring anadromous alewives to lakes that currently contain landlocked populations. The objectives of this research are to: (1) use molecular genetic markers to investigate the evolutionary origin of landlocked alewife populations; (2) conduct a comparative study examining the morphological and life history changes that have accompanied the shift from an anadromous to an entirely freshwater lifestyle; and (3) conduct a series of experiments to investigate the causes and ecological consequences of phenotypic changes in landlocked versus anadromous alewives.
Comparative data, including genetic markers, and phenotypic and life history traits, will be collected from anadromous alewife runs and landlocked populations throughout New England. Experiments will be conducted in several lakes in southern Connecticut. Common environment experiments will allow the partitioning of phenotypic differences into genetic and plastic (environmentally determined) components. Mesocosm experiments run in several lakes differing in zooplankton resource levels will test the relative strength of trophic interactions and the outcome of competition between anadromous and landlocked juvenile alewives.
The landlocked alewife, as a specialist planktivore in freshwater lakes, has been associated with changes in zooplankton community structure that often result in increased phytoplankton abundance and decreased water clarity, leading some to speculate that restored runs of the anadromous alewife will have similar effects. Evolved trait differences between anadromous and landlocked alewives, however, give reason to expect that anadromous alewives, in fact, will not exert strong top-down trophic control. Therefore, in contrast to the large effects of landlocked alewives, I predict that restored anadromous alewives will have very minimal effects on water quality. In addition, anadromous alewife runs will be restored to some lakes currently containing landlocked populations. If the two types are unable to interbreed, anadromous juveniles will face strong competition from well-established landlocked populations. Based on theoretical expectations, the outcome of this competition is predicted to depend on the initial abundance of zooplankton resources.