Changes in Largemouth Bass Growth, Condition, and Behavior in Response to a Large-Scale Habitat Enhancement in an Aging Reservoir

1. Reservoir aging and the resulting loss of structural habitat can limit fisheries, in particular growth rates of fishes. Habitat enhancement using artificial structure could provide the necessary resources to more efficiently transfer energy to Largemouth Bass and thereby increase population growth rate. We evaluated the effects of habitat enhancement on Largemouth Bass in a 60-year-old reservoir. We used radio telemetry to quantify seasonal home range sizes, habitat use, and daily movement of Largemouth Bass before and after a large-scale habitat enhancement (i.e., artificial habitat covered approximately 13% of the shoreline). Prior to the treatment, home ranges averaged nearly 8 hectares with a maximum of 25 hectares. Additionally, daily movements were very high with some Largemouth Bass moving as far as 3.5km in 24 hours. Our results one year post-enhancement showed that Largemouth Bass are attracted to the treatment sites and that growth rates and condition of memorable size Largemouth Bass are trending up. Additionally, we found that daily movement and home range sizes remained similar to the pre-enhancement period. So, condition improved and growth increased, but likely not because of decreased activity. Artificial habitat can be used in aging reservoirs to enhance available habitat to benefit sport fishes.