Human operation of continuum “continuous-backbone” manipulators remains difficult, because of both the complex kinematics of these manipulators and the need to coordinate their many degrees of freedom. We present a novel synergy-based approach for operator interfaces, by introducing a series of octopus-arm inspired grasp-synergies. These grasp-synergies automatically coordinate the degrees of freedom of the continuum manipulator, allowing an operator to perform kinematically complex grasping motions through simple and intuitive joystick inputs. This effectively reduces the complexity of operation and allows the operator to devote more of his attention to higher-level concerns (e.g. goal, environment). We demonstrate the grasp-synergies interface design in both simulation and hardware using the nine degree of freedom Octarm continuum manipulator.