For a solution of the diblock copolymer composed of a hydrophobic block and a weak polyelectrolyte block, we obtain regions of stable aggregate morphologies in pH-solution salinity plane with the aid of the self-consistent field theory in the strong-segregation approximation. Lamellar, cylindrical, branched cylindrical, and spherical aggregates have been considered in the large interval of pH and salinity. The morphology stability maps are obtained to help control self-assembly of aggregates by variation of pH and salinity of the medium. In qualitative agreement with experiment, our calculations predict the coexistence of long wormlike micelles with branched and spherical micelles in transition zones. We compare the results of our calculations with available computer simulation and experimental data on micelles and brushes (planar and curved) formed by a diblock copolymer with one polyelectrolyte block. We show that for both weak and strong polyelectrolytes the agreement between the theory and experiment is satisfactory in most systems.