Bomb Radiocarbon, Otolith Daily Increments and Length Modes Validate Age Interpretations of Chilean Jack Mackerel (Trachurus murphyi)

Ages of Chilean jack mackerel ( Trachurus murphyi ) in the southern Pacific Ocean were validated using three methods: 1) daily microincrement readings sagittal otoliths young-of-the year (YOY) fish to validate first annulus; 2) modal progression strong year-classes (PSYC) first, second and third annuli, 3) bomb radiocarbon analysis otolith cores absolute age older >38 cm fork length (FL). A Laird-Gompertz (LG) model was fitted (cm) at (days) relationship ranging from 3.4 25.0 FL 56 550 days age. The LG estimated a mean 22 end life, which large compared with through conventional ageing whole otoliths. comparison between annual growth bands otoliths, showed false increment formed 185 ± 34 translucent 352 79 days, corresponding annulus for 21.4 1.8 cm. PSYC coinciding recruits 2008 (age 0), tracked subsequent years high accuracy, attaining 23, 27 30 2009, 2010 2011, respectively. These modes identified as 1, 2 3 PSYC, matched 2, 4 5 increments Results confirmed that most ages correct, because Δ14C content adult core reference chronology. assayed based on chronology, ranged 7 13 sizes 39 60 FL. validation T. murphy addressed current study provided crucial information enhancing stock assessment output this important transboundary commercial species.