Abstract
Life history traits are heritable and evolve through natural selection to maximize organisms’ Darwinian fitness in their specific environments. The theory of life history evolution has developed during the last 100 years, and is rooted in the idea that these traits, to a certain extent, are heritable. Concurrently, ecologists have acquired evidence in support of the theory. Thus, a central focus of the present Special Issue is the adaptiveness of natural fish populations, and how environmental variables affect developmental processes within and across generations, which influence phenotypic developments. Habitat selection in stable and stochastic environments dampen abundance fluctuations and promotes phenotypically plastic life histories with morphs using different habitats. Reproduction is a major event in every life history, and the structure of mating systems depends on factors that allow males to obtain and monopolize mating resources. Habitat use and management, and the conservation of populations, are the other central themes of the volume. All habitats used by species require concern so that management actions do not impinge on their habitat selection. It is demonstrated how adult bull sharks use a seascape. For small demersal species, the structure and particle size in the bottom substratum is critical to secure feeding opportunities and shelter. Shelter is particularly important when invasive predators are introduced, and the native fauna meet a new threat against which they have no behavioral defense. Future research directions are discussed at the end of this introduction and in several of the separate papers.