As a result of these special conditions, tens of millions of years ago, during the ice age, when salmon could freely swim up and down Taiwan's waterways, groups of salmon, relying on their memory of the water's chemical composition, would swim upstream at spawning season to lay their eggs in the upstream portions of various rivers in Taiwan.
因此，千萬年前，仍處在冰封期，鮭魚可以自由上下來去台灣溪澗時，一群群年輕的鮭魚，靠著對水中化學物質的記憶，在產卵季節群起逆流而上，溯溪回台灣各個河流上游產卵。