place to place. This peculiar movement accounts for their common name. Their 

 large paired fins, both in the thoracic region, give these small fishes a striking 

 appearance. Many of them are beautifully and brilliantly colored. Un- 

 fortunately, like most dwellers in swiftly running water, they need an abund- 

 ance of oxygen and therefore seldom live long in aquaria where we might 

 admire and study them. 



A few fishes make long journeys for egg-laying. The Atlantic and the 

 Pacific salmon return from their feeding grounds at sea to deposit their eggs 

 in the headwaters of streams. Studies indicate that some return to the same 

 stream, and even to the same tributary, in which they hatched and from which 

 they migrated three or four years before. The Pacific salmon use all their 

 energy in this migration and die shortly afterwards. The Atlantic salmon 

 apparently survive, return to sea, and live to make more spawning trips in 

 other years. Along our coasts each spring multitudes of shad come hurling 

 themselves into the mouths of fresh-water streams to spawn, often in such 

 numbers that they force one another out of the water in their frenzied leapings. 

 Early settlers along the Atlantic coast were observant enough to notice the 

 coincidence of the spring runs of shad with the flowering of a common native 

 shrub, which they called the shadbush. In recent years power dams have kept 

 the shad from their old spawning grounds in many localities. Shad is still sold 

 commercially, however, and shad roe is considered a delicacy. The fishes 

 which come from salt to fresh water to spawn are called anadromous. 



The eel has reversed this process, the females growing to maturity in 

 fresh water but descending streams and going to sea to spawn. They are termed 

 catadromous. As they journey toward the sea their color changes from black 

 to shining white, and they reach the ocean as what the fishermen call "silver 

 eels". Here they join the males, which stay in brackish or salt water, and make 

 a pilgrimage to the South Atlantic, in the region of the Sargasso Sea. The 

 parents do not survive the egg laying. The baby eel is a flattened, ribbon-like 

 creature which, when it was first discovered, was taken for a small, adult, marine 

 fish. After about a year in this stage the American eel becomes more cylindri- 

 cal, takes to living near the surface, and continually swims toward our coasts. 

 It reaches them when it is only about three inches long. The males usually re- 

 main in brackish water, but the females continue their migrations, traveling by 

 night and resting by day, until they distribute themselves all through the 

 streams. The European eel migrates to almost the same breeding grounds as. 

 does the American species. 



Most fishes lay large numbers of eggs, those of most species being unpig- 

 mented, but some, like those of the sturgeon, being colored. A few fishes^ 

 Gamhusia, for example, bring forth living young. The males of many species 

 become more attractive during the breeding season, developing brilliant colors 

 on the body or, as in some of the minnows, pearl organs on the head. FertiUa- 



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