Previous work has demonstrated that survival of largemouth bass Micropterus
salmoides through the first year of life can be size dependent, favoring l
arger individuals. Because size, diet biomass, lipid accumulation, and ulti
mately overwinter survival of juveniles are typically positively related to
age, early spawning is clearly advantageous. However, a true understanding
of which largemouth bass cohorts contribute to the new year-class remains
somewhat unclear because these conclusions have largely been based upon fis
h collected during summer rather than fish collected during spring. Conceiv
ably, even earlier hatched cohorts of largemouth bass could have existed in
many of these studies, and these fish may simply not have survived to the
summer collection period. In order to assess this possibility, we quantifie
d first-summer survival of largemouth bass cohorts collected during 1992 an
d 1993 in Auburn, Alabama, ponds (which were 2-5 ha each). Our results indi
cate that it is early-hatched cohorts that likely contribute to the new yea
r-class. Although we found that early-hatched cohorts were lost between May
and July, these losses were not attributable to age-dependent mortality; i
nstead, sampling biases associated with avoidance of seines by older, large
r young-of-year largemouth bass appear to have driven these shifts. In addi
tion, because we found that size-dependent cannibalism during summer acted
to remove smaller, later-hatched largemouth bass, early hatching may enhanc
e survival during larval and early juvenile stages in southern systems (and
not just during the winter period). Given this information, fishery manage
rs may potentially be able to implement harvest regulations that are design
ed to protect large, early-spawning adults, thereby increasing the probabil
ity of producing a strong year-class by enhancing first-summer growth and,
ultimately, recruitment to adult stages.