How can bioenergetics help us predict changes in fish growth patterns?

• The von Bertalanffy growth function is an integrated bioenergetics function.
• Re-examining this function can help better understand how demographic and environmental variables may affect growth.
• Can use bioenergetics and ecological arguments to estimate density-dependent growth.
• Environmental variables will affect various components of growth differently.
• Incorrectly predicting growth variation can lead to serious errors.

Individual growth rates are an important component of ecological processes and models. Understanding how and when growth rates may vary is necessary for predicting changes in size-specific rates like reproductive output, age at recruitment to fishing gear and even market prices. The von Bertalanffy growth function (VBGF) is the most common growth function used today. This model is integrated from a simple bioenergetics model; re-examining the link between von Bertalanffy growth and bioenergetics will help predict how environmental and demographic rates influence growth rates over time. In this paper, we discuss how a simple bioenergetics model can help predict density dependent growth and demonstrate how to incorporate environmental drivers into the VBGF based on the original bioenergetics model. Finally, we discuss difficulties and pitfalls in linking environmental and demographic variation to changes in growth.