AUTHORS: James T. Lamer; Mike Spear; Brandon Harris; Sam Schaick; Jesse Williams; Andrew Mathis; Emily Szott; Kaiden Vinavich; Levi Solomon; Kris Maxson; Andrya Whitten; Jason DeBoer, Illinois Natural History Survey; Allison Lenaerts; Eli Lampo, Illinois Department of Natural Resources
ABSTRACT: Invasive carp can have detrimental effects on native ecosystems as they become established. Commercial and informed contracted harvest are currently the most impactful management strategies to reduce numbers and spread. However, evaluating effectiveness of this harvest to determine the proportion of the population impacted to help set management targets and allocate effort has been challenging due to invasive carp long-range movements, episodic recruitment, and difficulty obtaining population estimates through traditional means. Nevertheless, the need to assess population abundance or changes in relative abundance is still necessary to help guide and prioritize management efforts, help forecast future markets needed to grow the infrastructure and demand, and to understand dynamics and threats at the leading-edge populations. This talk provides an overview of some current invasive carp management evaluation tools being explored on the Illinois and Mississippi rivers by the state of Illinois and other state and federal partners. The choice of evaluation technique used varies depending on the state of invasion and the unique properties of each river system. In low density areas, techniques being explored include fisheries-independent monitoring in designated carp-likely habitat strata for silver carp and black carp, relative weight density-dependent baseline deviations in invasive carp and native surrogates, telemetry guided removals and harvest estimates from tagged fish in closed populations, and master chronologies to detect changes in growth over time. In high-density areas, several of the techniques used in low-density areas are combined with fisheries-independent monitoring and the resulting relative abundance estimates are grounded in density-dependent metrics while recognizing and accounting for differences in habitat strata and reach-specific structure.
