National Park Service Grant for St. Croix and Mississippi Rivers Asian Carp Food Web Research

Zooplankton are key primary consumers in aquatic systems, limiting algal blooms and in turn supplying food for higher invertebrates and fish. Both species of Hypophthalmichthys can decimate zooplankton populations, and in both natural and experimental systems this impact has been shown to increase algal blooms and harm other planktivorous fish and fish fry.

STATEMENT OF JOINT OBJECTIVES/PROJECT MANAGEMENT PLAN: Test the null hypothesis that food web structure does not differ between the St. Croix and Mississippi Rivers or between habitat types within rivers. Establish robust baseline data on pre-invasion food web structure to quantitatively evaluate future control and remediation efforts. Compare results with literature on Hypophthalmichthys spp. food preferences to identify habitats with food web structure most favorable to the growth and reproduction of invasive. Compare the St. Croix and Mississippi River Parks and identify rivers and/or habitat types with food web structure most dependent on pathways likely to be disrupted invasive carp. Results will be combined with known habitat preferences of the different carp species to direct removal and eradication policies and develop predictions about most likely impacts of carp on threatened and endangered species. Determine if gizzard shad are more dependent on planktonic (via zooplankton) or detrital carbon sources and if that varies in the presence of Asian carp (the latter portion of this objective depends on sampling in the Illinois River where Asian carp are abundant).
Zooplankton were sampled in Lake St. Croix and above the dam at St. Croix Falls (WI) in 2010 and 2011. Results from analysis of the 2010 samples are complete and intriguing. This project is complete with one caveat: zooplankton richness and abundance was an order of magnitude higher than expected based on similar systems. Sample preparation and counting took nearly three times as long as expected, so only samples from 2010 were counted. Samples from 2011 were taken but will be counted in fall, 2013 pending further support. While crustacean plankton preserve well, the smaller plankton like rotifers do not. If the samples are not analyzed by the end of 2013 they will no longer be useful given the importance of rotifers and protists in river systems.

RECIPIENT INVOLVEMENT: The College will provide the qualified researcher to conduct the project to meet the objectives and established management plan.

NATIONAL PARK SERVICE INVOLVEMENT: Participate and collaborate jointly with the Recipient in carrying out the scope of work. To provide a NPS technical representative to assist with specifics of the project as needed. Review and approve one stage of work before the next stage can begin. Review and approve proposed modifications or sub-grants, prior to award. Direct or redirect the work because of interrelationships with other projects. Immediately halt an activity if detailed performance specifications are not met. Oversee Recipient discretion with respect to scope of work, organizational structure, staffing, mode of operations and other management processes, combined with close monitoring or operational involvement during performance under this Task Agreement.