Evaluation of Asian carp use of a steeppass fish ladder

Asian carp continue to be a persistent threat to our Illinois waterways. Additional methods that aid in management, control, and removal are being explored. Asian carp are often attracted by water flow for upstream movements and spawning, a behavior we looked to evaluate to see it if it can be exploited for their removal. We assessed both nonnative and native fish passage using Whoosh Innovations steeppass fish ladder installed at The Nature Conservancy Emiquon Preserve’s water control structure. The objectives of this study were to evaluate (1) if native and nonnative fish will use a steeppass fish ladder, and (2) if they are using the ladder, what factors contribute to its use. During a five-day trial in September 2020, water was pumped from Emiquon to operate the steeppass and attract fish. We measured a suite of biotic and abiotic variables before, during, and after steeppass operation, including dissolved oxygen, temperature, conductivity, chlorophyll-a, turbidity, and daily zooplankton samples. We used Wi-Fi-controlled outdoor security cameras to record fish movement over the steeppass and into a holding pool. At the end of the trial, we collected a total of 76 individual fish from seven species out of the holding pool. Gizzard shad were the dominant catch (n=61), and no bighead or silver carp were collected. Most of the fish collected were between 150mm and 450mm. Complications due to low water level during the trial likely had a large influence on size distribution and species composition. We are planning to run additional trials in Spring 2021 with lessons learned from 2020, including adjusting the elevation of the steeppass off the river bottom and using an AI scanner to better capture fish passage. With successful fish passage, this research could have important implications for Asian carp management and native fish passage.