A meta-analysis and model comparison of juvenile salmon growth across different habitat types

Abstract

The size of an organism is an important factor for a variety of physiological and ecological processes. For fishes, larger size can increase long-term survival and provide a population level benefit. Therefore, threatened and endangered species management often focuses on supporting high quality habitat that provides growth opportunities. There are numerous habitat characteristics that can affect growth, including food availability, temperature, and habitat complexity. Understanding how growth responds to habitat types of different quality is the first step in determining what could lead to increased growth and potentially increased individual survival. We use Bayesian techniques to determine which of the differing methods is best for modeling the effects of habitat type and temperature on growth. To apply this method, we gather data from previous studies of the growth benefits of differing habitats and temperature regimes on Chinook salmon on the Sacramento River, CA, USA. We find a consistent growth benefit of floodplain rearing across multiple studies and show that a Ratkowsky model is the best for modeling this growth data. This information can specifically help managers model and protect the endangered and threatened Chinook populations in this system and more generally understand fish growth across differing habitat types.