[1] Stanford Univ, Hopkins Marine Stn, Dept Biol, Pacific Grove, CA 93950 USA
[2] Univ Manchester, Fac Biol Med & Hlth, Div Cardiovasc Sci, Manchester M13 9NT, Lancs, England
[3] NOAA, Northwest Fisheries Sci Ctr, Seattle, WA 98112 USA
[4] Stanford Univ, Hopkins Marine Stn, Tuna Res & Conservat Ctr, Pacific Grove, CA 93950 USA
[5] Univ Bordeaux, INSERM U1045, LIRYC Inst Rythmol & Modelisat Cardiaque, Campus Xavier Arnozan PTIB, F-33600 Pessac, France