The valuable sea cucumber Holothuria scabra, known as ‘sandfish’, has potential for restocking. However, there is little information available to determine the size of the no-take zones (NTZs) needed to protect the released animals so that they can form nucleus breeding populations. To do this, we measured short-term movement paths of released juvenile (1–105 g) and wild adult (130–690 g) sandfish in a seagrass bed in New Caledonia. We then developed an individual based model (IBM) to predict long-term dispersal of sandfish released as juveniles (1–16 g) at 1 individualm-2 within a 1-ha area, drawing on distributions of speed and directionality and the relationship between speed and animal weight from field data. Movement was non-random at the sampling scale used, since animals tended to turn