Fluid Friction of Fish Slimes

WHEN dissolved in water, the natural slimes of most of the fishes we have tested have a remarkable capacity to decrease greatly the friction of water when flowing in the turbulent state. In one species, a dilute solution of its slime was found to reduce the friction of water by as much as 65.9%; reductions of 57% to 63% were frequently obtained with the slimes of other species. These measurements have led us to the view that the slimes of many (but not all) fishes assist in locomotion by reducing the drag or resistance which water offers to their bodies.