596 KATUEAL HISTOEY OF AQUATIC ANIMALS. 



of mistake on the part of those making the assertion, and since the presumed or actual introduc- 

 tion of Shad into these waters, we cannot settle the question by actual identification of specimens. 

 " If the true Glupea sapidissima is natural to the waters of the Alabama, or if the plants in the 

 Ooosa in 1848, and the plant in Conlej^ Creek, near Montgomery, in 1856, were successful, then 

 there must exist in the waters of the Alabama certain conditions which are unfavorable to natiu'al 

 increase, and all the efforts of the United States Commission to establish an annual run of Shad 

 in the Alabama Eiver by artificial plantings will prove abortive. 



" On the other hand, if the planting operations of the United States Commission are success- 

 ful in establishing a run of Shad in this river, the result will prove that the Shad are not indigenous 

 to these waters and that previous plants were unsuccessful. Two or three years will settle this 

 question. 



" There seems to be nothing in the conditions presented by the Alabama Eiver to prevent the 

 establishment of a run of Shad in that river, unless the low temperature of the river during the 

 running season of the fish prevents maturity of the ova." 



The geographical range of the Shad, as already stated, was confined to the Atlantic coast of 

 the United States until, by the operations of the United States Fish Commission, its limits were 

 vastly extended. Euns of Shad, sufficiently large to be of commercial value, have been estab- 

 lished in several of the tributaries of the Mississippi Eiver, notably the Ohio Eiver; and the 

 several plants made from time to time in the Sacramento Eiver, on the Pacific coast, have resulted 

 in the colonization of this species in all the rivers of the Pacific slope, from the Sacramento to 

 Puget Sound. 



Migrations. — It is doubtful whether there is any general coastwise movement of the 

 Shad. That there is an occasional migration of this kind is evidenced by the following facts: 

 The Shad of the rivers of the South Atlantic coast, as a rule, have black-tipped caudal and 

 dorsal fins, which distinctive marks of coloration are absent in the Shad of more northern rivers; 

 and yet occasionally these southern Shad are caught as far north as the tributaries of the 

 Chesapeake and Delaware Bays. These fish have undoubtedly been born and bred in southern 

 waters, and their appearance so far north would indicate that occasionally this southern variety 

 strays beyond its normal range.' At one time^ it was imagined that the whole body of American 

 Shad, having wintered in the south, started northward with the new year, and as each river mouth 

 was reached a detachment would leave the entire mass for the purpose of ascending the river, the 

 last remaining portion of the immense school entering the Gulf of Saint Lawrence. 



At a later date it was thought more reasonable to suppose that the young fish, hatched out in 

 ■any particular stream, went out into the sea and remained within a moderate distance of the coast 

 until the period again occurred for their upward river migration. Their appearance, first in the 

 ■ extreme southern river of the coast, the Saint John's, and at later dates successively in the more 

 northern rivers, was thought to confirm this view. It will be seen, in the discussion of the relation 

 of the movements of the Shad to the water temperature, that this order of appearance when 

 preserved may be reasonably accounted for; there are, however, exceptions. For instance, the 

 lEdisto Eiver is many miles nortli of the Savannah, and yet the run of Shad in the former is 

 ^usually coincident with that in the latter. This leads us to believe that the Shad are generally 

 distributed along the coast at all times, entering the rivers as soon as the temperature of the 



' Report United States Fish Commission, part il, p. 48. 



'It may liere be mentioned tliat there are probably several well-defined hydrographical areas along the Atlantic 

 «oaat beyond each of which Shad indigenous to that area rarely stray. Each race has its own peculiar characteristics. 



