Bomb Radiocarbon
Composite image I designed for the cover of Marine and Freshwater Research
November 2011 Issue
Bomb radiocarbon dating of three important reef-fishes of the Indo-Pacific
Published 2011
Bomb radiocarbon dating of three important reef-fish species using Indo-Pacific ∆14C chronologies
Demersal reef fishes of the Indo-Pacific are under increasing pressure as a fisheries resource, yet many of the important life history characteristics required for suitable management are poorly known. The three fish species, eightbar grouper (Hyporthodus octofasciatus), ruby snapper (Etelis carbunculus) and the spangled emperor (Lethrinus nebulosus), are important components of fisheries and ecosystems throughout the Indo-Pacific. Despite their importance, age and growth information is incomplete. Age has been estimated for E. carbunculus and L. nebulosus, but validated age beyond the first few years is lacking, and for H. octofasciatus no age estimates exist. Bomb radiocarbon dating can provide age estimates that are independent of growth-zone counting, but only if appropriate reference ∆14C chronologies exist. In this study, a series of ∆14C records from hermatypic corals were assembled to provide a basis for bomb radiocarbon dating in the western Indo-Pacific region. Results provided: 1) valid age estimates for comparison to age estimates from two facilities investigating growth-zones in otolith thin-sections; 2) support for age estimation protocols using otolith thin-sections; and 3) the information necessary for further refinement of age estimation procedures. Estimates of longevity from bomb radiocarbon dating agree with some prior studies. Hyporthodus octofasciatus, E. carbunculus, and L. nebulosus were all long-lived with life spans of at least 43, 35, and 28 years, respectively.
Authors: Allen H. Andrews, John M. Kalish, Stephen J. Newman and Justine M. Johnston (I was honored to be asked to take lead authorship because of my contribution to the paper).
Introduction for cover image:
The atmospheric detonation of thermonuclear devices in the 1950s and 1960s created a change in naturally occurring radiocarbon (∆14C) that can be traced as a time-specific signal in marine environment, such as with hermatypic corals (inserted plot). Pictured is the cloud produced in 1952 during Operation Ivy by the Mike test ("M" = megaton) at Enewetak Atoll, Marshall Islands (source: U.S. Government under public domain). This change in radiocarbon has become a useful tool in providing validated estimates of age for fishes, such as the pictured spangled emperor (Lethrinus nebulosus, Richard Ling). In this issue, Andrews et al. provide the first application of this sort in the Indo-Pacific region to three important reef-fish species.
Below is a shot of the final journal cover with volume details.
