  We complete previous investigations on the statistics of velocity
fluctuations arising from a random distribution of point vortices in
two-dimensional hydrodynamics. We show that, on a statistical sense, the
velocity created by a point vortex is shielded by cooperative effects on a
distance $\Lambda \sim n^{-1/2}$, the inter-vortex separation. For $R\gg
\Lambda$, the ``effective'' velocity decays as $R^{-2}$ instead of the ordinary
law $R^{-1}$ recovered for $R\ll \Lambda$. These results are similar to those
obtained by Agekyan [Sov. Astron. 5 (1962) 809] in his investigations on the
fluctuations of the gravitational field. They give further support to our
previous observation that the statistics of velocity fluctuations are
(marginally) dominated by the contribution of the nearest neighbor.
