This is a pre-copy-editing, author-produced PDF of an article accepted for publication in ICES Journal of Marine Science following peer review. The definitive publisher-authenticated version Guerra, A, Rodriguez-Navarro, AB, Gonzalez, AF, Romanek, CS, Alvarez-Lloret, P & Pierce, GJ 2010, 'Life-history traits of the giant squid Architeuthis dux revealed from stable isotope signatures recorded in beaks', ICES Journal of Marine Science, vol 67, no. 7, pp. 1425-1431 is available online at http://icesjms.oxfordjournals.org/content/67/7/1425