Fish & Water - Sounds Wild
Salmon Senses

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Salmon senses

I approach a coastal stream and a school of salmon darts away, quickly regrouping on the other side of the stream. Salmon are equipped with a range of senses, including good eyesight. Fish eyes function like our eyes, with a pupil, lens, and a retina filled with sensory cells: rod-shaped cells that work best in low light, and cone-shaped cells that detect colors. Their eyes are adapted for life in water. A fish's lens is spherical and retains that shape whereas the lens in our eye is oval and flexible and changes shape with the visual range.

Fish also have taste buds, located in the mouths and throats of most fish, but some fish also have taste buds on their gills and even their fins. Catfish have taste buds on "whiskers" near their mouths, and some catfish have taste buds all over their bodies.

The nasal organs of fish function only to detect odors. This sensory system is particularly important to salmon. Salmon remember the specific smell of the water in their birth or natal streams, and remember how it changes as they migrate to the sea as smolts. They use the memory of the smell to help them hone in on their natal stream when they return to spawn.

Sharks, tuna and salmon can detect the Earth's electromagnetic field, which allows them to maintain a compass heading at sea. Salmon spend one to five years in the ocean and migrate thousands of miles at sea before returning to their natal streams to spawn. Their ability to navigate at sea helps them to return to the coastal areas where they first entered saltwater; then their sense of smell helps lead them directly to their natal stream.