Surveys and investigations for sportfish management in lakes and rivers in Illinois: annual Report July 1, 2020 through June 30, 2021

摘要: Black Crappie (Pomoxis nigromaculatus), White Crappie (Pomoxis annularis), and Bluegill (Lepomis macrochirus) are some of the most widely harvested species of fish in Illinois lakes. The high harvest rates of these species make them particularly well suited for evaluating the potential of regulations for managing size structure. In general, regulation outcomes for various types of recreational fisheries have been variable and interpreting the causes for regulation success or failure has been hindered because most studies evaluating regulations were conducted over too short a period, lacked proper controls for comparison, and did not include creel data to document if there were changes in angler catch rates. In Study 101.1, we continued pre-treatment data collection on 12 reservoirs chosen in consultation with Illinois Department of Natural Resources (IDNR) fisheries biologists to be part of an experimental assessment of crappie and Bluegill regulations. The sampling regime for water quality, prey resources, and fish assemblages was conducted from May-November 2020. During 2020, we were unable to conduct creel surveys because of safety concerns associated with the COVID-19 pandemic. The suspension of creel surveys resulted in a one year delay in collecting angler fishing effort and harvest data on two lakes in the Bluegill portion of this investigation; therefore, implementation of experimental Bluegill regulations have been postponed until 2022. Creel surveys resumed in spring 2021 and synthesis of all pre-treatment human dimension data will be reported in the next segment.Biological data collected during this reporting period …