  Although at small Bjorken x gluons originated from different nucleons in a
nucleus overlap in the longitudinal direction, most of them are still well
separated in the transverse plane, therefore cannot fuse. For this reason the
gluon density in nuclei cannot drop at small x below a certain bottom bound,
which we evaluated in a model independent manner assuming the maximal strength
of gluon fusion. We also calculated gluon shadowing in the saturated regime
using on the Balitsky-Kovchegov equation, and found the nuclear ratio to be
well above the unitarity bound. The recently updated analysis of parton
distributions in nuclei \cite{eps08} including RHIC data on high-pT hadron
production at forward rapidities, led to astonishingly strong gluon shadowing,
which is far beyond the unitarity bound. This indicates a misconception in the
interpretation of the nuclear suppression observed at HRIC.
