  With the aim to show explicitly the non stationarity of the Zakharov spectra,
obtained analytically as the stationary solution of the four-wave kinetic
equation for stochastic nonlinear surface gravity waves[1,2], we have
calculated directly the proper kinetic integral by means of two independent
algorithms[3,4] both for an isotropic and anisotropic angular distribution of
spectra given on the restricted frequency band.
