The class is talking about the salmons run various species of pacific salmon make a round trip from the small streams where they are born to the sea and then back to the stream of their origin, where they spawn and die. This round trip is known as the salmons run. The end of the salmons run is the beginning of the next generation, pacific salmon hatch on the head waters of a stream as fry. The fish then migrate downstream via rivers and eventually to the ocean, where they require several years to mature while in the sea, salmon from many river systems school and feed together. When mature the salmon form into groups of common geographic origin and migrate back toward the river. They emerge from this juveniles. Is it true that they find their way home by their sense of smell? During the first stage of their return? They navigate by the position of the sun. But later when they reach the river leading to their home stream, their keen sense of smell takes over. Just what is it? They can smell the other fish. The water flowing from each stream carries a unique scent. This scent comes from the types of plants, soil, and other components of that stream. This centers apparently imprinted in the memory of a salmon fry before it migrate to the c I remember having a real shock when I was hiking. Once I was looking at a waterfall and I saw a salmon jump up about ten feet.