Kissimmee River Fish Study

  • Passive tracking station at S65A. The truck box is open here to show the battery and receiver inside. The solar panel is facing south for optimal charging capability.

  • Passive tracking station at PC33. Two antennas were installed at this station in anticipation of the high water extending the flood plain on either side of the installation during the rainy season.

  • Mobile fish tagging station in Lake Kissimmee.

  • Largemouth bass being tagged January 21, 2020 by Rachel Grey and Brad Fontaine.

  • Antenna being passed through the body cavity of a large mouth bass during surgery. A hollow needle was used to create the exit and guide passage.

  • Largemouth bass receiving sutures to close incision site.

  • Largemouth Bass #040 recaptured April 27 in Lake Kissimmee after being tagged February 3 in Pool-A and recaptured and released by an angler in Pool-A on February 23. Suture site appears to be healing as does antenna exit. The antenna appears to have been clipped, presumably by an angler who did not know what it was.

The Kissimmee River Fish Study grew out of a need to work with the South Florida Water Management District (SFWMD) to assess the effect of the Kissimmee River Restoration project on fish populations within that area. The Kissimmee River Fish Study has been designed to track the movements of largemouth bass (Micropterus salmoides) within two restored sections of the Kissimmee River; the primary goal of the study is to document the response of adult largemouth bass to annual variations in flow and water quality within restored sections of the Kissimmee River. A secondary goal is to calculate recruitment, growth and mortality rates of largemouth bass and bluegill (Lepomis macrochirus) and evaluate environmental factors influencing these rate functions. A third and final goal is to establish realistic management targets for fish populations and management actions needed to enhance and protect the river’s fisheries. 

Historically, the Kissimmee River followed a meandering 166 km path from central Florida south to Lake Okeechobee. In 1971 a 90 km long canal (C-38) was constructed between Lake Kissimmee and Lake Okeechobee. This canal eliminated flow through most of the historic river channel and disconnected the river from the expansive floodplain marsh. Fish habitat was degraded, and the quality of the river’s fish community declined.  

Attempts to restore portions of the Kissimmee River began in 1999 with the goal of returning the ecosystem to conditions that resembled those present prior to channelization. The first phases of restoration construction, Phase I through Phase IV, were completed between 1999 and 2009. More than 21km of the C-38 canal were filled in, flow was reestablished to more than 38 km of historic river channel, and portions of the river were reconnected with the floodplain marsh. 

The U.S. Army Corps of Engineers' Final Integrated Feasibility Report (IFR) and Environmental Impact Statement states that “comprehensive studies of fish community structure, dynamics, and habitat utilization are required”. The IFR also states that “fish and wildlife monitoring will provide a basis for adaptive management measures that may be needed to facilitate early recovery as well as subsequent persistence of the full complement of natural resource values”. This study hopes to provide a basis for management of fish populations. SFWMD has observed summer fish kills in the restored sections of the Kissimmee River during summer high flows and wants to know the survival rate of adult largemouth bass within the restored sections of the river during these events and whether fish move down into the restored river from upstream following these summer hypoxia (absence of oxygen) episodes.  

Passive and active telemetry of largemouth bass is the primary method of monitoring their movements and habitat use during the study. Researchers tagged 50 largemouth bass in 2020 with internal radio tags and released 10 into Lake Kissimmee, 10 into a water body known as Pool A and 30 into the restored sections of the river. A biologist actively tracks the fish using an antenna and receiver on a boat to locate individuals. When fish are located, water quality and habitat parameters are noted. There are three stationary receivers set up near passage from the lake to Pool A, between Pool A and the C38 canal and at the bottom of Phase I of restoration that can detect fish passing through these areas.  

Largemouth bass and bluegill will be collected in winter/spring 2021 using electrofishing techniques in the restored section of the Kissimmee River. Otoliths (ear bones) will be removed from a representative sample of each species to estimate relative year-class strength, length at age, growth rate, and total annual mortality.  

At the end of the 24-month tracking period, researchers will attempt to collect the remaining largemouth bass implanted with transmitters by boat electrofishing. These bass will be sacrificed, and their otoliths extracted for microchemistry analysis to investigate if there are unique markers that can identify the origin of the fish within the Kissimmee River Basin (e.g. Kissimmee River, Lake Kissimmee, Lake Istokpoga, Lake Okeechobee) or if the fish have been exposed to hypoxia during the period.  

To finish the Kissimmee River Fish Study, an additional 50 fish need to be tagged in the winter of 2020/2021 as well as continuing to track tagged bass through the rest of 2020 and 2021. Otolith analysis still must be completed. Work to be completed after the Kissimmee River Fish Study is finished include preparing a final report for South Florida Water Management District with management recommendations. The potential publication of findings in a fisheries journal will also be evaluated.  

The primary researchers on this project are Reid Hyle and Rachel Grey out of the Palm Bay Freshwater Fisheries office. Brad Fontaine and Arthur Bernhardt have also helped with work on the project. Chuck Hanlon is the SFWMD project manager for this grant and is the primary collaborator outside FWC. FWC is coordinating with Justin Lewis from the University of Florida on otolith microchemistry. The primary researchers received help from 7 other FWRI biologists for the initial tagging event: Stephen Stang, Ryan Henry, Drew Dutterer, Summer Lindelien, Chris Anderson, Jason O’Connor, and Travis Tuten as well as one Division of Freshwater Fisheries Management biologist Steven Kramer.  

Managers of the restored portion of the Kissimmee River will have an immediate use for the results of this study as well as organizations planning river restoration projects in the future. SFWMD should incorporate as much as practical into development of an environmental water management plan as part of the system operating manual for the Kissimmee River Basin.