By systematic variation of the oxygen concentration it is demonstrated that the oxygen vacancies in the CuO2 planes are indeed the predominant pinning centers in Bi2Sr2CaCu2Oδ+6 (Bi-2212) single crystals. Both the critical current density and the pinning energy increase proportional to the square root of the vacancy concentration. We also show that a change of the superconducting parameters upon annealing, predominantly of λL(0), gives rise to a considerable decrease of the critical current.