Modelling growth in fish with complex life histories

Understanding growth in living organisms is central to the study of individuals, populations and communities. In fisheries, in particular, growth modelling is fundamental to the management of fish stocks that can constitute important economic resources. The scientific literature is abundant in studies attempting to define the growth trajectory of different fish species but often little consideration is given to the ecological components of the fish's life history. This review examines ontogeny of fishes with complex life histories, in particular how different phases can effect growth and the interpretation of growth models. Using the blackspot seabream (Pagellus bogaraveo) as an example, we explore alternative approaches to understanding growth in a species that undergoes both sex reallocation and ontogenetic vertical migration. More flexible models are required in order to accurately represent significant lifetime events, specifically accounting for periodical changes in the growth trajectory. Finally, model evaluation and interpretation need to be adequate to the task, particularly when outcomes are used to support resource management, in order to address concerns regarding conservation, sustainability, and successful management in the long term.