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Age and Growth Program

Bomb Radiocarbon Age Validation

Mushroom cloud

During the height of the Cold War in the late 1950s to early ‘70s, the United States, Russia, and other countries exploded so many nuclear warheads that it significantly raised the amount of C-14 (also known as bomb carbon) in the atmosphere and in the surface layers of the ocean. Because C-14 has a half-life of 5,730 years, its presence remains in earth’s air and oceans for millenniums and serves as a timestamp in fish otoliths.

When using bomb carbon to age fish, we match the increase in C-14 radioactivity found in otoliths with recognized amounts in the atmosphere or in biological structures of known age.

The essence of this age validation method is as follows: if we know the year a fish was collected and have determined the fish’s age in the laboratory (that’s fish ageing), then we know when the otolith core was laid down and, accordingly, how much C-14 activity there should be in that core.

There is bomb C-14 age validation research currently in process at the AFSC for Pacific ocean perch, Dover sole, yellowfin sole, and northern rockfish. The results will be made available as soon as they are published.



  • WISCHNIOWSKI, S. G., C. R. KASTELLE, T. LOHER, and T. E. HELSER. 2015. Incorporation of bomb-produced 14C into fish otoliths. An example of basin-specific rates from the North Pacific Ocean. Can. J. Fish. Aquat. Sci. 72:879-892. DOI: 10.1139/cjfas-2014-0225.
  • HELSER, T. E., C. R. KASTELLE, and H-L. LAI. 2014. Modeling environmental factors affecting assimilation of bomb-produced Δ14C in the North Pacific Ocean: Implications for age validation studies. Ecol. Model. 277:108-118.
  • KASTELLE, C. R., T. E. HELSER, B. A. BLACK, M. J. STUCKEY, D. C. GILLESPIE, J. McARTHUR, D. LITTLE, K. D. CHARLES, and R. S. KHAN. 2011. Bomb-produced radiocarbon validation of growth-increment crossdating allows marine paleoclimate reconstruction. Palaeogeogr., Palaeoclimatol., Palaeoecol. 311:126-135.
  • HALTUCH, M. A., O. S. HAMEL, K. R. PINER, P. McDONALD, C. R. KASTELLE, and J. C. FIELD. 2013. A California Current bomb radiocarbon reference chronology and petrale sole (Eopsetta jordani) age validation. Can. J. Fish. Aquat. Sci. 70:22-31.
  • Kastelle, C. R., D. K. Kimura, and B. J. Goetz. 2008. Bomb radiocarbon age validation of Pacific ocean perch (Sebastes alutus) using new statistical methods. Can. J. Fish. Aquat. Sci. 65:1101-1112.
  • Kastelle, C. R., D. M. Anderl, D. K. Kimura, and C. G. Johnston. 2008. Age validation of Dover sole (Microstomus pacificus) by means of bomb radiocarbon. Fish. Bull., U.S. 106:375-385. Online.
  • Craig Kastelle, and Thomas Helser. 2010. Regional Environmental Factors Affecting Bomb-Derived Radiocarbon Age Validation Studies. AFSC Quarterly Report Feature (April-May-June 2010). Online.

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