“As the spawning season approaches, fishes move toward the shores of ponds and lakes or upstream in the creeks. Some of them, such as perch and sunfish, only swim in among nearby weeds or protecting stones. The journeys vary from such short ones to the famous migrations of river salmon, extending over hundreds of miles; but they all end at spawning grounds or nesting sites. During this time color differences between male and female appear or become more marked.”