Water Resources Research Act Program

Details for Project ID 2004CT38B

The dual influence of Alewife, Alosa pseudoharengus, on inland water quality

Institute: Connecticut
Year Established: 2004 Start Date: 2004-04-01 End Date: 2006-02-28
Total Federal Funds: $50,255 Total Non-Federal Funds: $140,586

Principal Investigators: David Post

Project Summary: Across North America dams are being removed and fish ladders are being installed allowing migratory fish species access to inland waters that have been isolated, in many cases, for a century or more. This is an experiment of unprecedented scope and scale, with implications for ecological processes ranging from species conservation to water quality management. In coastal systems, such as those found along the Atlantic seaboard, anadromous fishes are the focus of considerable attention. While species such as the Atlantic salmon have garnered the preponderance of attention, ecological interactions and water quality may be most strongly influenced by less glamorous, but historically more abundant fishes such as the River Herring (a name used to collectively refer to alewife, Alosa pseudoharengus and blueback herring, Alosa aestivalis). I seek funding to explore the influence of river herring restoration efforts on the water quality and ecological function of inland water in Connecticut and throughout New England. Of particular interest are the influences of restoring anadromous alewife to lakes and ponds where no pelagic zooplanktivore currently exists, and the restoration of anadromous alewife into lakes and ponds where landlocked populations of alewife currently reside. Objectives: The long-term objectives of this research are to test 1) the ecological and evolutionary implications of the shift from an anadromous to an entirely freshwater lifestyle, including shifts in the relative roles of young-of-the-year anadromous and landlocked alewife on food web structure and water quality, and 2) to quantify the role of anadromous alewife as nutrient vectors. Approach: I will use experimental food web manipulations in mesocosms to evaluate differences in food web impacts of landlocked and anadromous alewife in their first summer of life. Nutrient excretion experiments and modeling will be used to evaluate the role of anadromous alewife as nutrient vectors. Molecular genetic approaches will be employed to evaluate the origin and potential for rapid life history shifts from anadromy to an entirely landlocked life history. Expected results: In the first year of this study I will 1) provide proof of concept for rearing larval anadromous alewife for future stocking efforts and larval anadromous and landlocked alewife for experimental research, 2) test for differences in the effects of anadromous and landlocked alewife in their first summer of life on water quality, 3) produce a general model of nutrient loading by anadromous alewife at various stages of population recovery, and a model specific to the management of Rogers Lake, CT, 4) begin to evaluate the evolutionary origin of landlocked populations of alewife as a first step in attempting to understand the outcome of secondary contact between anadromous and landlocked alewife populations, and 5) begin to monitor Linsley Pond and Rogers Lake to gather pre-manipulation data before fish ladders are installed and anadromous alewife recover into these lakes. These results will address a number of the most pressing research needs by the CT DEP inland water management group, and lay the groundwork for future studies on competition between anadromous and landlocked alewife and the long-term effects of alewife restoration on lake ecosystem processes including water quality.