SELECTIVE ATTRACTION OF SALMON

The ability to separate or sequester individual fish identified as req uiring further inspection would represent a milestone in the developme nt of inspection and control systems for fish in sea nets. This paper reports work on a technique which enables a visually identified fish t o be selectively drawn away from the other fish and towards the camera . The development of a device capable of sequestering the fish thus lo calised is the subject of future development. The technique for attrac ting the fish relies on the development of a conditioned response in t he whole population which associates a light stimulus with food delive ry. This is found to be a relatively easy and rapid process. The targe t fish is then selectively exposed to this stimulus and so is attracte d to the light source while the others remain undisturbed. Tank trials suggest that a target fish can be selectively attracted to the camera with a reliability approaching 70%. Further work is needed to establi sh whether this concept can be used in sea nets at commercial stocking densities. (C) 1997 Elsevier Science B.V.