402 AMERICAN FISHES. 



purpose of spawning. In these upward migrations the schools of mature 

 fish ascend the rivers either until obstructed by impassable falls or dams, 

 or until the volume of water becomes very inconsiderable. Before artificial 

 impediments were placed in the rivers, the limit of this movement was the 

 natural and insurmountable falls to be found at the head of almost all of 

 our principal streams. For example, in the Savannah River the Shad used 

 to ascend to the Falls of Tallula, at the very source of the river in the 

 northern part of Georgia. In the Potomac they ascend as high as the 

 Great Falls. In the Susquehanna River, in which there exist no natural 

 obstructions, their migration extended up into the State of New York, a 

 distance of several hundred miles above the present limit. On the Hudson 

 River they ascended to Glens Falls. On the Connecticut at one time they 

 went as high as Bellows Falls, but recent obstructions in this river have 

 materially reduced the extent of their range. 



The age at which the Shad reaches maturity and becomes capable of 

 reproducing is not definitely determined ; it is generally held by fish 

 culturists, however, that the female Shad attains this condition when three 

 or four years old. The favorite spawning grounds, or "Shad Wallows," 

 as they are termed by the fishermen, are on the sandy flats which border 

 the streams, and the sand-bars which are found at intervals higher up the 

 river. When the fish have reached suitable spawning grounds and are 

 ready to cast their eggs, they move up to the flats seemingly in pairs. The 

 time of this movement is usually between sundown and ii p. m. When 

 in the act of coition they swim close together and near the surface, 

 their back fins projecting above the water. The rapid, vigorous, spas- 

 modic movements which accompany this operation produce a splashing in 

 the water which can be plainly heard from the shore, and which the fisher- 

 men characterize as " washing." 



The number of eggs in the ovary of a Shad, as in all other fish, bears a 

 certain relation to the size and weight of the fish. As the result of ex- 

 perience in the artificial propagation of the Shad we conclude that a ripe 

 roe Shad weighing four or five pounds contains from 20,000 to 40,000 

 eggs, the average number being about 25,000. A much larger number, 

 however, has been obtained from some individuals. In the season of 

 1 88 1 we obtained from a single Shad, weighing about six pounds, over 

 60,000 impregnated eggs; again, in 1S80. on the Potomac River, the 

 yield of eggs from a single Shad was over 100,000. These were full-sized. 



