Otolith biochronologies reveal latitudinal differences in growth of Bering Sea yellowfin sole Limanda aspera

Annual growth patterns in the hard parts of marine organisms are often related to factors in the physical environment; investigators are increasingly borrowing methods from the field of dendrochronology (tree-ring science) to explore these relationships. When applied to otoliths of yellowfin sole Limanda aspera, an abundant and commercially important flatfish, this approach has demonstrated a strong positive correlation between otolith growth and bottom temperature in the southeastern Bering Sea. In the present study, we assess whether the biochronology-growth relationship extends to yellowfin sole collected at higher latitudes. Two new northern Bering Sea biochronologies, one from the Bering Strait region and one near St. Matthew Island, were developed and compared with the southeastern Bering Sea biochronology using mixed effects modeling. Despite large distances (up to 600 km), a high degree of synchrony was observed among all three chronologies. However, subtle differences in growth among the three regions were revealed upon closer examination. The relative amplitude of otolith growth differed among the three chronologies, with stronger negative anomalies in the south and stronger positive anomalies in the north. Differences in average length at age were also detected, with fish growing slower to greater lengths at higher latitudes. Lastly, the Bering Strait biochronology had the weakest and most localized relationships with climate variables, suggesting effects of climate may not be felt uniformly across the regions examined. Biochronologies may thus provide a useful tool in evaluating potential biological responses to projected climate change across a species' range.