Captive gummy sharks, Mustelus antarcticus, form hypermineralised bands in their vertebrae during winter

Abstract

The subjective interpretation of the growth increments in shark vertebrae and uncertainty over the temporal periodicity of their formation decrease confidence in the accuracy of ages estimated from increment counts. To determine the periodicity with which growth increments are formed in the vertebrae of gummy shark, Mustelus antarcticus, fluorochrome dyes were injected into captive sharks at quarterly intervals. Variation in the vertebral growth rate between fluorochrome labels was examined and compare with measurements of the density of mineralisation of vertebral sections. The slowest rates of vertebral growth and the highest radiographic densities were found in the vertebral tissues forme..