The influence of variable discharge on hatching and age-0 growth was examined for fluvial specialist and habitat generalist species of black bass Micropterus spp. in two southeastern U.S. rivers, the Flint River, Georgia (unregulated), and Tallapoosa River, Alabama (regulated by several hydropower dams).  In 2008-2010, 285 Largemouth Bass M. salmoides (generalist) and 254 Shoal Bass M. cataractae (specialist) were collected from two reaches of the Flint River.  In 2010-2011, 309 Alabama Bass M. henshalli (generalist) and 216 Redeye Bass M. coosae (specialist) were collected from two regulated reaches and one unregulated reach of the Tallapoosa River.  Successful hatching of black bass in both rivers generally occurred from late March to early June when water levels were low and stable.  Hatching distributions of all black bass were generally unimodal with little evidence of spawning disruption, except for Alabama Bass in the most-regulated reach of the Tallapoosa River, which appeared to be disrupted by large discharge events.  Mean growth of both species in the Flint River varied from 0.64-0.82 mm/d across reaches and years; Shoal Bass generally grew faster than Largemouth Bass in all reach-year combinations.  Largemouth Bass growth was inversely correlated to discharge variation in one reach, but Shoal Bass growth was not correlated to discharge variation in either reach.  Alabama Bass and Redeye Bass growth in the Tallapoosa River was similar to rates observed for congeners in the Flint River; Alabama Bass grew faster than Redeye Bass.  Growth of both species was inversely related to discharge variation in 5 of 6 reach-species combinations; the only exception was for Redeye Bass in the less-regulated reach.  Results from this study suggest that variable discharge has less influence on successful reproduction of black bass than has been reported for other fishes, but growth may be more affected by discharges resulting from anthropogenic sources than those associated with the natural regime.

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