Lead-radium dating provides a framework for coordinating age estimation of Patagonian toothfish (Dissostichus eleginoides) between fishing areas

Patagonian toothfish (Dissostichus eleginoides) or ‘Chilean sea bass’ support a valuable and controversial fishery, yet their life history is not well understood and longevity estimates range from ~20 to >50 years. In this study, lead–radium dating provided valid ages for juvenile to older adult groups, which were consistent with the counting of otolith growth zones in transverse otolith sections, and longevity estimates exceeding 30 years. Lead–radium dating revealed minor biases between the radiometric age and interpretation of growth zone counting for regional fishing areas monitored by two facilities, Center for Quantitative Fisheries Ecology (CQFE) and the Central Ageing Facility (CAF), using different age estimation techniques. For CQFE, under-ageing of ~3.3 years was observed for individuals with estimated ages under 20 years. For the CAF, ages were overestimated for young fish and underestimated for the oldest fish. Lead–radium dating detected underlying problems in coordinating age estimation between geographically separated fish stocks, and provided a framework to objectively assess otolith interpretation and growth modelling between laboratories based on age-validated data.