  It is shown that, under a small perturbation of lump (soliton) for
Davey--Stewartson (DS-II) equation, the scattering data gain the nonsoliton
structure. As a result, the solution has the form of Fourier type integral.
Asymptotic analysis shows that, in spite of dispertion, the principal term of
the asymptotic expansion for the solution has the solitary wave form up to
large time.
