  In this paper, we first investigate necessary optimality conditions for
problems governed by systems describing the flow of an incompressible second
grade fluid. Next, we study the asymptotic behavior of the optimal solution
when the viscoelastic parameter tends to zero, and prove that the corresponding
sequence converges to a solution of an optimal control problem governed by the
Navier-Stokes equations whose optimality conditions are recovered by passage to
the limit.
