High trophic overlap among four air-breathing marine predators of the northern coast of San Jorge Gulf (central Patagonia) during the Late Holocene

CÉVOLI, ANTONELLA; SVOBODA, ARIADNA; VALES, G. DAMIÁN

Workshop; IV Taller de Arqueología e Isótopos Estables en el Sur de Sudamérica; 2023

CADIC

Knowledge of past marine food webs is essential forunderstanding the structure and functioning of current ecosystems, as well asfor predicting their future responses to environmental changes. The aim of thisstudy is to assess trophic resource partitioning among four air-breathingmarine predators inhabiting the northern coast of San Jorge Gulf during theLate Holocene. For this, we analysed stable isotope ratios of nitrogen and 15 13C) in bone collagen of sea lions Otaria flavescens (n = 5), fur seals Arctocephalus australis (n = 20), penguins Spheniscus magellanicus (n = 7) and cormorants Fam.Phalacrocoracidae (n = 10) remains dated from 3300 to 600 14C BP recovered from coastal archaeological sites ofthe study area. The SIBER plots showed -space, although the sea lions showed awider isotopi 13 15N values among taxa 2 = 3,61, p = 0,192). These results suggest a highdegree of trophic overlap among these predators during the Late Holocene andagree with the findings of previous works in other regions of the SouthwesternAtlantic Ocean (i.e., Península Valdés and adjoining areasand the Beagle Channel). Our next goal is to investigate the trophic resourcepartitioning in modern conspecifics to determine whether the regional marine foodweb has changed as a result of environmental shifts that occurred in the last3000years.