EGU24-19585, updated on 11 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Temperature alters the size selectivity of Southern Ocean fish

Patrick Keith1,2, Simeon Hill2, Lucía López-López3, Benjamin Rosenbaum4,5, Ryan Saunders2, Geraint Tarling2, and Eoin O'Gorman1
Patrick Keith et al.
  • 1University of Essex, School of Life Sciences, Colchester, United Kingdom of Great Britain – England, Scotland, Wales (
  • 2British Antarctic Survey, High Cross, Madingley Rd, Cambridge, CV3 0ET, UK
  • 3Ecosystem Oceanography Group GRECO, Oceanographic Centre of Santander (CN IEO, CSIC)
  • 4EcoNetLab, German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
  • 5Institute of Biodiversity, Friedrich Schiller University Jena, Jena, Germany

A primary response of many marine ectotherms to warming is a reduction in body size, to lower the metabolic costs associated with higher temperatures. The impact of such changes on ecosystem dynamics and stability will depend on the resulting changes to community size-structure, but few studies have investigated how temperature affects the relative size of predators and their prey in natural systems. We utilised >3,700 prey size measurements from ten Southern Ocean lanternfish species sampled across >10° of latitude to investigate how temperature influences predator-prey size relationships and size-selective feeding. As temperature increased, predators became closer in size to their prey, driven primarily by a decline in predator size and an increase in the relative abundance of intermediate-sized prey. The potential implications of these changes include reduced top-down control of prey populations and a reduction in the diversity of predator-prey interactions. Both of these factors should reduce the stability of community dynamics and ecosystem resistance to perturbations.

How to cite: Keith, P., Hill, S., López-López, L., Rosenbaum, B., Saunders, R., Tarling, G., and O'Gorman, E.: Temperature alters the size selectivity of Southern Ocean fish, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19585,, 2024.