Ecological Archives E094-130-A1

Paul E. Bourdeau, Kevin L. Pangle, Emily M. Reed, Scott D. Peacor. 2013. Finely tuned response of native prey to an invasive predator in a freshwater system. Ecology 94:1449–1455.

Appendix A. Details of the methods related to collection and maintenance of experimental organisms.

Collection and maintenance of experimental organisms

All D. mendotae (and diaptomid copepods for experiment 3) were collected from Lake Michigan using a 64-mm mesh zooplankton net with a closed cod-end (closed to protect organisms from being damaged on the mesh often present on cod-ends) towed vertically through the entire water column. Collections occurred along the 45–110 m contour approximately 8 km offshore of Muskegon, Michigan (43°14'03’’N, 86°14'98’’W) during time periods in which Bythotrephes were present. Prior to experiments, Daphnia were maintained in 4-L vessels in aged Lake Michigan water at 20°C with a 14 h light: 10 h dark light regime. They were fed Nanochloropsis limnetica at approximately 6 mg C/L. Five invertebrate predator species were collected in a similar fashion to D. mendotae, but with a 363-um mesh zooplankton net, at two different locations near Muskegon and used for production of predator cue water to be used in the experiments within 24–48 hours of the experiment (details of collection sites/dates, experiment dates, and incubation times for the predators are described for each experiment separately in Appendix B [Table B1]). Perca were collected from a nearshore location (5-m depth) on Lake Michigan, near the mouth of the Muskegon River. They were then maintained in a 50-L glass aquarium, and fed a mixture of zooplankton collected from Lake Michigan for 24 days prior to their use for production of fish kairomone water.

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