Welcome to the interactive web schedule for the 2019 Midwest Fish & Wildlife Conference! Please note, this event has passed. To return to the main Conference website, go to: www.midwestfw.org.
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CONFERENCE SCHEDULE UPDATES & CHANGES: As a result of the prolonged government shutdown, we experienced a number of cancellations and changes to the schedule. Cancellations and changes are listed here (as of January 26, 2019).
AUTHORS: Zachary Witzel, Western Illinois University; Kevin Irons, Illinois Department of Natural Resources; James Lamer, Illinois River Biological Station, Illinois Natural History Survey, and Western Illinois University
ABSTRACT: Bigheaded carp (bighead carp and silver carp) are highly invasive fishes in the Mississippi River System and can be detrimental to native fishes and ecosystems. To limit their impact and further expansion, fishermen have been contracted through state and federal agencies to remove bigheaded carp using predominantly gill nets. Mesh size of entanglement gears determines the size structure of fishes able to be captured. To increase efficiency and effectiveness of bigheaded carp harvest and minimize the capture of bycatch, it is important to understand the relationship of gill net mesh size with the size structure of persistent populations. Therefore, the objective of our study is to determine the size of bigheaded carp and commonly encountered bycatch that are effectively caught in different sized gill nets based on their size (bar size = 7.62, 8.89, 10.16, 10.8, 11.43, 12.7, 13.335, and 15.24 cm). Gill nets were used in pools 16 through 20 on the Mississippi River to capture silver carp (n=445) and bighead carp (n=72). Multiple areas were targeted for their capture including backwater, and main channel areas of bigheaded carp. With this information managers will be able to more efficiently target bigheaded carp if knowledge of population size structure is available.
