1 “I“C First AŶŶual CoŶfereŶĐe Cliŵate ChaŶge aŶd its iŵpliĐatioŶs oŶ eĐosysteŵ serviĐes aŶd soĐiety, “epteŵďer Ϯϯ-24, 2013, Castello Carlo V Lecce, Italy Has the ocean contributed to the decline of European eel recruitment? Results of a 40-year simulation experiment Paper M. Schiavina 1* , R. Casagrandi 1,2 , M. Gatto 1,2 , L. Bonaventura 3 , S. Masina 4,5 and P. Melià 1,2 1 Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Via Ponzio 34/5, I-20123 Milano, Italy; 2 Consorzio Interuniversitario per le Scienze del Mare, via Isonzo 32, I-00198 Roma, Italy; 3 MOX, Dipartimento di Matematica "F. Brioschi", Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20123 Milano, Italy; 4 Centro Euro-Mediterraneo per i Cambiamenti Climatici, Via Aldo Moro 44, I-40127 Bologna, Italy; 5 Istituto Nazionale di Geofisica e Vulcanologia, Via Aldo Moro 44, I- 40127 Bologna, Italy; *Corresponding author: m.schiavina@gmail.com 1. Abstract The European eel stock is declining since the late 70s. The causes of this decline are still debated, but most likely include habitat loss, water pollution, parasite impact, climate change and overfishing. In particular, climate change is deemed to have affected the larval migration of this catadromous fish from its reproductive area (the Sargasso Sea) to European coasts. Temperature changes might have changed the structure of the plankton community and decreased food availability, while changes in oceanic circulation might have affected migration routes and increased exposure to predation. So far, these (non mutually exclusive) hypotheses have been tested only through correlation analyses among aggregated indices of recruitment, oceanic circulation and environmental features. Attempts to describe eel migration by means of Lagrangian simulations with coupled physical-biological models have been limited to short-term analyses and did not provide any information on possible changes of