Life history variability in maturity and the influence of environment in Atlantic Salmon, Salmo salar, and Bullethead Parrotfish, Chlorurus sordidus and C. spilurus, under climate change

Abstract

Life history transitions are periods between lifecycle stages defined by physiological, morphological, or spatial change. By assessing the timing of transitions, we increase our understanding of the trade-offs in traits to maximize fitness. One such transition is maturity, which we study because it is required for successful reproduction. In this thesis, we explore maturation strategies and the drivers of their plasticity in two fish taxa. Here we show evidence of (1) inter- and intra- population variability in mature male parr age at maturity driven by intrinsic population-level differences and thermal experience in Atlantic Salmon and (2) population demography as a driver of size at phase change in protogynous Bullethead parrotfish. Identifying the drivers of plasticity in maturity traits and how maturation timing may change with environmental variability in fish taxa can provide ecological predictions of population dynamics and inform fisheries management.