Midwest Fish & Wildlife Conference 2019

AUTHORS: Jeremy Hammen*, U.S. Fish & Wildlife Service, Columbia Fish & Wildlife Conservation Office; Jahn Kallis, U.S. Fish & Wildlife Service, Columbia Fish & Wildlife Conservation Office; Emily Pherigo, U.S. Fish & Wildlife Service, Columbia Fish & Wildlife Conservation Office; Jason Goeckler, U.S. Fish & Wildlife Service, Columbia Fish & Wildlife Conservation Office

ABSTRACT: Effective fisheries management requires representative data that can be collected in an efficient, reasonable timeframe. This can be difficult for invasive species, like Bigheaded carp, where conventional methods can be limited in their ability to assess populations. Recent gear development and evaluation efforts have provided crucial information on the advancements in sampling methods and tools for Bigheaded carp. Information gained from these studies could be used to give managers and researchers the ability to appropriately assess these Bigheaded carp populations over a temporal and spatial scale. A pool-wide Bigheaded carp monitoring design using one of these novel gears, the electrified dozer trawl, was developed to evaluate the population characteristic differences throughout the Illinois River. Preliminary (first year) results demonstrated that population demographics at the pool level differed throughout the Illinois River. Relative abundance and size structure change throughout the Illinois River and small fish (< 200mm) were absent from the upper two pools. Additionally, it appears that habitats (main channel border, side channel, backwater) may differ in Bigheaded carp demographics but results after the first year were not significant likely due to small sample size. Estimated sample sizes based on minimizing variation in relative abundance and size structure appear to be representative through one year. Early results suggests that management of Bigheaded carp in the Illinois River may be different from pool to pool. Additionally, further refinement of the sampling efforts may be possible (i.e., smaller sample size) to make monitoring these populations more efficient and effective. Maintaining successful management activities for Bigheaded carp will require cost-effective sampling efforts in a representative and effective matter. This work will benefit those management efforts in the Illinois River and this study could provide the framework to expand throughout their Mississippi River basin where Bigheaded carp are located.