Abundance, size structure, and spawning locations of Robust Redhorse stocked in the Ogeechee River, Georgia
September 2010 - December 2011
- US Fish and Wildlife Service
- GA Department of Natural Resources
As part of the ongoing recovery effort for the robust redhorse, refugial populations have been established in several rivers in GA and SC. One such population was established in the Ogeechee River, GA, which has received about 40,000 fingerling robust redhorse during the period 1997-2004 (J. Evans, GDNR, pers. comm.). The overall status of this population, including size-structure, abundance, and habitat use is unknown. Further, successful reproduction and recruitment of wild-spawned fish has not yet been documented for this population. The goal of the proposed work is to evaluate reproduction and recruitment success for the population of robust redhorse stocked into the Ogeechee River. Specific objectives include: 1) estimating the size structure of the population to determine if reproduction and recruitment are occurring, 2) documenting spawning location(s), and 3) estimating the number of individuals in the adult population. The first component of the project will address the question of where in the river robust redhorse are spawning and will be based on the use of radio telemetry to locate spawning aggregations during the spawning season. During the fall, 30 robust redhorse will be captured with boat-mounted electrofishing and surgically implanted with ATS radio transmitters. The radio-tagged fish will be tracked monthly after the initial tagging until March 2011. Beginning in April 2011 and continuing through the end of June 2011, the fish will be tracked weekly to identify where in the system robust redhorse are spawning. These data should allow for habitat characterization and protection of spawning site(s) within the Ogeechee River. The second component will address the questions of: a) how many robust redhorse have survived in the Ogeechee and; b) what is the size structure of this population. This component will be based on a capture recapture approach in which boat-mounted electrofishing will be used to sample robust redhorse throughout their known range in the Ogeechee River. Additional surveys that are based on seines and other gear types will specifically target juvenile robust redhorse during late summer and fall.