Growth of Freshwater Drum from Lotic and Lentic Habitats in Alabama

We analyzed variations in the age and growth of freshwater drum Aplodinotus grunniens in Alabama rivers and reservoirs. Lotic environments produced significantly more robust freshwater drum (associated with higher growth rates) than did lentic settings. Shorter reservoir retention times (more lotic reservoirs) also produced more robust and faster‐growing freshwater drum, which supported the hypothesis that hydraulic‐based habitat was an important variable in determining freshwater drum condition and growth. Linear declines in relative weight and percent lipid were revealed along a hydrologic gradient in Lake Logan Martin and were strongest in older freshwater drum. Von Bertalanffy predictions supported these results but also exposed a unique caveat: If freshwater drum lived long enough (>12 years), they were ultimately able to grow to larger sizes (>L∞) in reservoirs. Freshwater drum may be capable of moving between available lentic and lotic habitats during their lifetime to maximize invertebrate and fish prey bases. These results exposed interesting possibilities for the biology and movement of freshwater drum, which apparently live much longer (>30 years) than originally thought and may be of some use in extensive ecological time series analyses.