The effect of suspended sediments on ninespine stickleback,Pungitius pungitius,and golden shiner,Notemigonus crysoleucas,in a current of varying velocity

Synopsis Ninespine stickleback, Pungitius pungitius, and golden shiner, Notemigonus crysoleucas, were exposed at 5 and 20°C to 0, 15, 75 and 150 JTU (Jackson Turbidity Units) of suspended sediments. Fish were tested in a trough inclined at 2.3° with an inflow rate of 27 ml sec^-1. Changes in swimming behaviour were only noted for golden shiner and at 20°C and 15, 75 and 150 JTU. Under these conditions golden shiners were more active, changing from location to location in the apparatus significantly more often at higher than at lower concentrations of suspended sediments. This behaviour is compatible with a fleeing response from a stress inducing agent.