Hatch Timing and Growth of Age-0 Largemouth Bass in Wisconsin

Largemouth bass have protracted spawning periods that can last up to several weeks. As a result, growth, total length (TL), and recruitment of age-0 largemouth bass may be regulated by hatch timing, but these relationships have not been thoroughly examined for largemouth bass in northern lakes. Our objective was to determine if hatch timing influences TL and growth rate of age-0 largemouth bass in Wisconsin lakes. Initial results suggest that largemouth bass hatching in Wisconsin lakes can occur over periods exceeding 40 days. Total length of age-0 bass was negatively related to hatch timing (i.e., earlier hatched fish attain greater TLs), but these relationships were often weak. Hatch timing also explained significant variation in daily growth rates, with late-hatched fish typically growing faster than those hatching early in the year. Due to differences in length observed at the end of their first growing season, it is likely that early-hatched age-0 largemouth bass will experience higher survival than fish hatching later in the year if overwinter survival is length-dependent. Climatic conditions that promote early hatching of largemouth bass or extend growing seasons could increase bass recruitment, resulting in relatively high abundance of adult bass in the future.