Physics to Fish: Allometric Scaling and the Mid-trophic Ladder

Raghu Murtugudde, University of Maryland, ragu@essic.umd.edu (Presenting)
Patrick Lehodey, CLS, plehodey@cls.fr
Inna Senina, CLS, isenina@cls.fr
John Sibert, PFRP-UH, sibert@hwaii.edu
Laurent Bopp, LSCE, laurent.bopp@lsce.ipsl.fr

With the impacts of climate change quite clearly manifesting themselves in all aspects of the Earth System, projections of climate change must now be quantified not only for the physical components but also for ecosystem and biogeochemical responses. Well-known allometric scaling laws can now be used to go from molecular level reactions involved in metabolic processes to spatially explicit population dynamics. The relation between body mass and biomass and between habitat temperatures and metabolic rates at rest are combined with the empirical scaling information for age at maturity to habitat temperature to develop a top-predator model going from primary production up the mid-trophic ladder. The age-structured mid-trophic forage between 2cm-20cm consisting of crustaceans, cephalopods, and fish are predicted given the primary production from an OGCM-biogeochemical model. The age and size structured tune population dynamics are predicted for the past 50 years and for climate change scenarios. The utility of the metabolic theory of ecology vs dynamic energy budgets need to be explored further but it is evident that the time for such models even if they minimally realistic, has arrived.