Do fish find the bait by sight or smell?

The sense of smell is highly developed in fish and it is probably mainly through this sense that they Iocate their food. Scientists, however, have not yet been able to determine accurately the relative perceptive powers of the various sense organs in fish: Most fish, it is believed, are attracted to the bait by both the sense of smell and sight. The sense of smell is highly developed in most fish and many species are probably attracted to the bait chiefly by that sense. A few years ago the United States Fish and Wildlife Service declared: “From what is known at present it is believed that the sense of smell, along with that of touch, plays a greater role in the life of a fish, as far as obtaining its food is concerned, than that of sight.” Fish that depend upon the sense of smell to locate the bait are not easily caught by artificial baits, whereas fish that bite chiefly by sight are most easily caught by such baits. The sense of sight in most fish seems to be limited more to the perception of changing lights and shadows, and they will snap most quickly at a moving object. There is a common but erroneous notion that a fish smells with its gills. The nose is the seat of the smelling sense in all fish. The Canadian Fisheries Research Board reported some years ago that as a general rule the warmer the water the larger the pieces of food swallowed by a fish. Fishermen were advised to use small pieces of bait when the water is cold and larger pieces when the water is warm.