Insights into mixing and movement of South Pacific albacore Thunnus alalunga derived from trace elements in otoliths

•We measured trace element concentrations in South Pacific albacore otoliths.•Classification accuracy to geographically distant capture locations was high.•Some evidence of different larval sources for the west and east South Pacific.•Cycling in otolith Sr:Ca and Ba:Ca was observed across life-history transects.•Patterns may reflect seasonal north-south movements across oceanic fronts. Information on the movement and stock structure of commercially important tunas underpins the effective management of exploited populations. In the case of the South Pacific albacore (Thunnus alalunga) stock, longstanding questions remain regarding the degree of connectivity among larval pools, the migration routes of juveniles and adults and the biophysical factors influencing these processes. We measured trace elements (Li, Mg, Mn, Cu, Sr, Ba, Pb, Ca) in albacore otoliths collected across a broad geographical range in the South Pacific Ocean to address these knowledge gaps. Capture locations in French Polynesia, New Caledonia and New Zealand were discriminated with high accuracy (overall 85% of individuals correctly classified) based on analyses at the otolith edge (reflecting the final