Bomb-produced radiocarbon age validation of Greenland halibut (Reinhardtius hippoglossoides) suggests a new maximum longevity

Bomb-produced radiocarbon (14C) was used to validate age estimates of Greenland halibut (Reinhardtius hippoglossoides) using a stained otolith cross-section method. The Delta 14C in eastern Bering Sea (EBS) Greenland halibut otoliths was compared to both EBS and Gulf of Alaska (GOA) Pacific halibut (Hippoglossoides stenolepis) otolith reference chronologies to evaluate which reference chronology was most suitable, and to quantitatively estimate age determination bias. Using Bayesian analysis and a coupled-function model, the Delta 14C in the Greenland halibut showed greatest similarities to the Delta 14C in the GOA reference chronology. Although the model indicated under ageing, the bias was not large. Assigning an age less than the true age by more than a one year is about 73%, and less than the true age by more than 2 years is only about 25%. When considering the age at which Greenland halibut is only 7.5% of its maximum longevity (50+ years) and that the probability of underageing by 3 years being less than 5%, it is likely that between-age-reader variation will cancel out any systematic bias that exists in the age determination protocols. Prior to the use of stained cross-sections the maximum age was 38 years, now a maximum age of 53 years is supported.

Automated summary

Bomb-produced radiocarbon was used to validate age estimates of Greenland halibut, with the results showing similarity with the Pacific halibut from the Gulf of Alaska. Despite some under ageing, the bias in age determination was not significant.