Sensuous usually means a powerful appeal to the senses or to the esthetic faculties; such as, the sensuous delicacy of a rose petal. Sensual, on the other hand, refers more to some sexual application; such as, a sensual sculpture of a nude.

The difference between the two words was the original reason for creating the expression sensuous. The poet, John Milton, is said to have invented the word in order to have a synonym for sensual, minus the association with sex. He used the word in an often-quoted formulation of what poetry should be: “simple, sensuous, and passionate.”

Apparently most fishermen know that fish have a line running along each side of their bodies. It may be distinct or obscure. In some species it’s straight; in others, curved or zigzag. It can be described as a “finely stitched seam where the fish was sewed together”.

“The proper term for this ‘seam’ is the lateral line, and it houses a marvelous, intricate mechanism that operates as a kind of supersense. A fishery biologist once explained it thus: ‘If you could combine your sense of touch with your hearing, making the two into a single sense, you’d probably come close to understanding the kinds of responses the lateral line of a fish relays to its brain.’ ”

It’s through this system that the fish feels/hears low-frequency vibrations, or sounds, carried through the water. The line allows the fish to monitor an amazing mass of information about its surroundings. It instantly knows when there’s the slightest current change, and senses, the direction. The biologist who first explained this supersense, to the author said, “The most minute changes in water temperature also are sensedby lateral-line pickup, and tiny electric charges are zipped from the line pores along nerves to the brain. Such changes may trigger a feeling of comfort, discomfort, or alarm.”

The lateral line also monitors balance, an especially important function in water, where, without a foolproof system, a fish could hardly tell when it was upright. “Perhaps most intriguing,” the biologist explained, “is how the lateral-line system operates a kind of sonar, identifying [within modest range] objects and other fish.”

As the fish swims, its motion sends out vibrations that bounce off nearby objects, bounce back, and are picked up.

The inner ear of the fish, located in its head, hears fairly distant sounds, but it can’t always pinpoint them precisely. “The lateral line knows instantly from which side a vibration originates. Because of the length of the line, the fish is able to triangulate and locate it exactly, especially as the fish moves. The sound is pinpointed as coming from an exact compass point. Fish can find their way in the dark and locate prey by lateral-line monitoring.”