Maternal influences on population dynamics: evidence from an exploited freshwater fish.
We used a field experiment, population modeling, and an analysis of 30 years of data from walleye (Sander vitreus; a freshwater fish) in Lake Erie to show that maternal influences on offspring survival can affect population dynamics. We first demonstrate experimentally that the survival of juvenile walleye increases with egg size (and, to a lesser degree, female energy reserves). Because egg size in this species tends to increase with maternal age, we then model these maternal influences on offspring survival as a function of maternal age to show that adult age structure can affect the maximum rate at which a population can produce new adults. Consistent with this hypothesis, we present empirical evidence that the maximum reproductive rate of an exploited population of walleye was approximately twice as high when older females were abundant as compared to when they were relatively scarce. Taken together, these results indicate that age- or size-based maternal influences on offspring survival can be an important mechanism driving population dynamics and that exploited populations could benefit from management strategies that protect, rather than target, reproductively valuable individuals.
Venturelli
Paul A
PA
Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario M5S 3G5, Canada. venturelli@lsu.edu
Murphy
Cheryl A
CA
Shuter
Brian J
BJ
Johnston
Thomas A
TA
Van Coeverden de Groot
Peter J
PJ
Boag
Peter T
PT
Casselman
John M
JM
Montgomerie
Robert
R
Wiegand
Murray D
MD
Leggett
William C
WC
D000818:Animals; D003247:Conservation of Natural Resources; D017753:Ecosystem; D005260:Female; D005618:Fresh Water; D008297:Male; D008954:Models, Biological; D010473:Perciformes / Q000502:physiology*; D011157:Population Dynamics; D012098:Reproduction; D012744:Sex Ratio