AUTHORS: Seth J. Fopma, Iowa Department of Natural Resources
ABSTRACT: Suitable overwintering habitat is considered to be a limiting factor for Centrarchids in the Upper Mississippi River (UMR). Lock and dam construction in the 1930’s greatly increased total aquatic area of the UMR and provided deep backwater areas favorable to Centrarchid populations; however, sediment deposition has reduced the quantity and quality of deep water habitats presumably limiting overwinter survival. The U.S. Army Corps of Engineers’ Upper Mississippi River Restoration Program (UMRR) initiated a Habitat Rehabilitation and Enhancement Project (HREP) project on Pool 12 of the UMR in 2013. Project objectives included the development of approximately 63 acres of suitable overwintering habitat in four backwater lakes found throughout Pool 12 where insufficient overwintering habitat was thought to limit Centrarchid survival. Habitat restoration in Tippy Lake occurred during 2017 with the goal of increasing the availability of habitat suitable for overwinter survival. Pre-project telemetry efforts utilized radio telemetry during the winter of 2014-2015 to estimate habitat utilization distribution of crappie (n = 50). Telemetry efforts resumed during the winter of 2023/2024 to assess crappie habitat utilization post-project. Relatively recent advances in acoustic telemetry technologies offered researchers the opportunity to compare telemetry methods during the post-project evaluation. Radio (n = 20) and acoustic (n = 20) tags were implanted into crappie November 15-16, 2023 and fish were tracked through the first week of June 2024. Habitat utilization distributions pre and post-project were similar when evaluated using data generated from radio telemetry efforts but differed from estimates calculated using acoustic telemetry data.
