Are maternal effects in fish adaptive or merely physiological side effects?

Abstract

Abstract In general, maternal effects in fishes have received little attention except as confounding factors in quantitative genetic experiments. However, due to commercial interest in certain fish species, considerable research provides evidence for large and ubiquitous maternal effects in fishes. Here, we review that evidence with a special emphasis on the potential, or demonstrated, adaptive nature of those effects. There is virtually no direct evidence for adaptive maternal effects in fishes; however, strong inferential evidence exists. The bulk of the published research deals with maternal effects in oviparous species, although important work has also been done on viviparous species. Maternal effects on offspring size are best documented; however, evidence for maternal effects on disease resistance, survival and mortality, embryonic levels of hormones, mRNA, environmental contaminants, and behavior is presented as well. We conclude that the study of adaptive maternal effects in fishes is still rudimentary and predict that further research in this area will provide useful and important insights into the evolution of fishes.