“Efficacy of Upstream Removal Efforts of Asian Carp in the Illinois River: Insights from a Multi-Year Partnership Between Biologists and Commercial Fisherman”

The Illinois Department of Natural Resources is faced with the task of reducing impacts of Asian Carp (AC).  Although the best control strategy for these fish is unknown, much energy has been directed toward contracted commercial fishing efforts to remove large quantities of AC biomass. The goals of removal efforts are two-fold:  to reduce AC populations where commercial fishing is not profitable or permitted, and to prevent further spread of AC into naive environments, namely, the Great Lakes. From 2010-2013 over 1,000 miles of nets has been deployed in the upper Illinois Waterway, removing 160,656 of AC (over 2.1 million pounds). Over this period, recapture rates of marked individuals have been extremely high (26-52%),with annual exploitation rates in backwater areas near 90%, suggesting a fishery vulnerable to this solution. Commercial catches combined with hydroacoustics and side scan sonar indicate that numbers and size of AC in the upper reaches have declined. Although evidence of seasonal immigration is present, declining catch rates over time suggest an overall declining population. While discussions about developing new technologies (electrical/chemical) and physical separation between these historically isolated watersheds continues, an old tool, commercial fishing, has contributed to reducing the threat of further spread.