Determinants of individual reproductive success in a natural northern pike population, and implications for fisheries management

Knowledge about the relative reproductive success (RSS) of individual fish along with their determinants in the wild is rudimentary. We measured the RRS for an exhaustive sample of sexually mature pike (N=341) in a natural population inhabiting a small lake in Germany. In total, 215 viable offspring were sampled in the study year and assigned by multilocus microsatellite genotype-based parentage assignment to their parents. Only 43.2 % of all potential females and 21.5 % of all males recruited at least one viable young-of-the-year (YOY) to the population. The RRS was not significantly related to body size for both sexes, but there was a clear trend for larger males exhibiting higher RSS. There was no evidence for reproductive senescence, but large and old female pike spawned significantly earlier in the season than smaller fish. The RRS of females was positively related to fast early juvenile growth. This result extends the already known selection for fast juvenile growth to increase chances of survival in this strongly cannibalistic species by a novel finding about the importance of fast juvenile growth for reproductive fitness of female pike later in life. Our findings have practical implications in terms of selection of broodstock for stocking purposes.