Alligator gar as a centenarian species: extending lifespan estimates using bomb radiocarbon and laser ablation-accelerator mass spectrometry

Abstract

Context The potential lifespan of alligator gar (Atractosteus spatula) is currently unknown. A previous study applied bomb radiocarbon (C-14) dating to establish ages >60 years, but maximum age was limited by the rise of bomb-produced C-14 in the 1950s. Aims An exceptionally large specimen (2.6 m, 148 kg) was captured in Mississippi and otolith growth zones revealed an age estimate of 95 years. This specimen provided an opportunity to apply new technology to validate the lifespan of alligator gar. Methods Developments in accelerator mass spectrometry (AMS) led to technology that measures( 14)C continuously from carbonates (laser ablation-AMS), as opposed to single sample C-14 analysis. Key results Use of laser ablation AMS on the 2.6-m alligator gar otolith, and two smaller fish aged >60 years, supported ages that were older than original estimates by 5-20 years. Conclusions Our study indicates that alligator gar age can be underestimated for the largest fish, maximum recorded length is 2.6 m based on a historical photograph, and lifespan is at least 75-95 years with support for an age of 100 years for the 2.6-m fish. Implications An increase in lifespan of this magnitude would affect our understanding of population dynamics and recovery efforts.

Keywords

accelerator mass spectrometry; age validation; Atractosteus; Lepisosteiformes; longevity; maximum age; maximum recorded length; otolith

Published in

Marine and freshwater research
2024, Volume: 75, number: 8, article number: MF24024Publisher: CSIRO PUBLISHING

SLU Authors

• Andrews, Allen

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    
  • University of Hawaii at Manoa

UKÄ Subject classification

Fish and Aquacultural Science


Publication identifier

DOI: https://doi.org/10.1071/MF24024

Permanent link to this page (URI)

https://res.slu.se/id/publ/130226