  We investigate the effects of anisotropy on the stability and dynamics of
vortex cluster states which arise in Bose-Einstein condensates. Sufficiently
strong anisotropies are shown to stabilize states with arbitrary numbers of
vortices that are highly unstable in the isotropic limit. Conversely,
anisotropy can be used to destabilize states which are stable in the isotropic
limit. Near the linear limit, we identify the bifurcations of vortex states
including their emergence from linear eigenstates, while in the strongly
nonlinear limit, a particle-like description of the dynamics of the vortices in
the anisotropic trap is developed. Both are in very good agreement with
numerical results. Collective modes of stabilized many vortex cluster states
are demonstrated.
