Improving estimates of climate-driven body size changes and range shifts in fishes by accounting for fine-scale spatial heterogeneity

Fish are generally predicted to “shrink” (grow faster but attain smaller adult body sizes) when the oceans warm.

However, observations from natural systems show high variability among species, and this could be because body size responses are usually evaluated as averages over large spatial scales. This overlooks spatial heterogeneity in temperature, warming trends, and the distribution of species.

Species also tend to shift their geographical range to track temperatures they are adapted to, meaning they do not necessarily experience warming.

This project aims to advance our understanding of climate impacts on body size and the spatial distribution of fishes by explicitly accounting for spatial heterogeneity and local-scale responses using state-of-the-art geostatistical models.

We will quantify the degree of warming species experience and contrast that to the overall ecosystem warming, evaluate the role of fishing and other potentially confounding variables, and estimate at which spatial scales body size trends are correlated.

The project starts with local and regional case studies to resolve specific interim aims and ends with a global analysis of size and range shifts using data collated throughout the project.

This will provide a unique test of the generality of body size changes in the ocean due to climate change on a global scale, and how range shifts may allow species to avoid warming, which is crucial for improving climate impact assessments and fisheries management.