The degree that UV-B absorbing compounds provide UV-R protection was examined in four early developmental stages of the sea urchine Sterechinus neumayeri from Cape Armitage, McMurdo Sound. Adult Sterechinus were collected over their bathymetric range of distribution and the concentration of UV absorbing compounds, mycosporine-like amino acids (MAAs), in the gonadal tissues was quantified. Viable ... embryos and larvae obtained from these same individuals were used for laboratory and in situ experiments to assess the effects of UV-dose on development. Exposing these developmental stages to natural solar irradiances under the ice provides information about differential effects of UV-R on embryos and larvae from populations at different depths. In this way, the relative sensitivity of these life-history stages to UV-R can be correlated with their initial MAA concentrations. Cyclobutane pyrimidine dimer formation was analysed from samples.