Ergodicity of the 3D stochastic Navier–Stokes equations driven by mildly degenerate noise

We prove that any Markov solution to the 3D stochastic Navier–Stokes equations driven by a mildly degenerate noise (i.e. all but finitely many Fourier modes are forced) is uniquely ergodic. This follows by proving strong Feller regularity and irreducibility.