Adaptation enables natural populations to survive in a changing
environment. Understanding the mechanics of adaptation is therefore
crucial for learning about the evolution and ecology of natural
populations, and for better conservation and management of natural
resources such as fish stocks. In this review we focus on the impact of
random sweepstakes on selection in highly fecund populations. In random
sweepstakes the distribution of individual recruitment success is highly
skewed, resulting in a huge variance in the number of offspring
contributed by the individuals present in any given generation. We also
describe selective sweepstakes which are well approximated by recurrent
selective sweeps of strongly beneficial allelic types arising by
mutation. We demonstrate that both types of sweepstakes reproduction may
facilitate rapid adaptation. Finally, we review an important case study
in which a model of recurrent selective sweeps is shown to essentially
explain population genomic data of the highly fecund Atlantic cod, with
broad implications for studying the evolution and ecology of highly
fecund populations across domains of life.