  We present an exact diagonalization study of the electron momentum
distribution n(k) in small clusters of t-J model for different hole
concentrations and t/J. Structures in n(k) which were previously interpreted as
a `large' Fermi surface are identified as originating from the well known
many-body backflow. To obtain reliable information about the true Fermi
surface, we focus on the regime t=<J, where the backflow effect is weak and
suppress the formation of a bound state by introducing a density repulsion
between holes. We find clear signatures of a Fermi surface which, contrary to
widespread belief but in agreement with recent photemission experiments and
Monte Carlo studies for the Hubbard model, takes the form of small hole
pockets. Spin ordering is shown to be irrelevant for this form of the Fermi
surface. Comparison of the scaling of n(k) and that of the quasiparticle weight
with t/J indicates that these pockets persist also for t>J.
