Abstract. The ensemble CUE (q) of truncated random unitary matrices is a deformation of the usual Circular Unitary Ensemble depending on a discrete non-negative parameter q. CUE (q) is an exactly solved model of random contraction matrices originally introduced in the context of scattering theory. In this article, we exhibit a connection between CUE (q) and Fisher's randomturns vicious walker model from statistical mechanics. In particular, we show that the moment generating function of the trace of a random matrix from CUE (q) is a generating series for the partition function of Fisher's model, when the walkers are assumed to represent mutually attracting particles.