604 NATURAL HISTORY OF AQUATIC ANIMALS. 



extent that the Shad under certain circumstances spawn in salt or brackish waters. Experi- 

 ments have, however, been made to verify this supposition, but have proved unsuccessful. 

 Whilst impregnation under such conditions has been shown to be possible, and development has 

 proceeded to a certain point, yet before the hatching took place the development of the embryo 

 broke down. The annual migrations .of the Shad into our streams are made apparently for 

 the sole purpose of reproduction, excepting in the Saint John's River, Florida, where their first 

 movement into the river seems to be attributable to an influence other than that above mentioned. 

 The time of these migrations into the rivers varies with the geographical position of the river. As 

 a general rule, it is usually later as we proceed farther to the north, though we find some excep- 

 tions. It may be stated generally that this migration takes place as Boon as the continental 

 waters have become warmer than the salt- water areas into which they discharge. The schools of 

 fish having entered the streams, ascend until they have reached suitable spawning grounds. The 

 deposit and fertilization of the eggs having been accomplished, their development commences, and 

 in a few days, the period varying with the temperature, the young fish, bursting their shells, make 

 their appearance. These remain in the rivers, feeding and growing all summer, and leave'late in 

 the fall, at which time they are two or three inches in length. The life history of the Shad from 

 this time is unknown to us. The young fish, having disappeared, do not again come under our 

 observation until they return as mature fish to deposit their spawn. 



The motive of their movement into the rivers being for purposes of reproduction, we would 

 expect that with the accomplishment of this desire the mature fish would return to salt water. 

 This is the general impression among fishermen, and may be true as a general fact, but there are 

 instances on record where a full-grown Shad in good condition has been taken in our rivers long 

 after the spawning season is over, and even late in autumn. One of the largest Shad I have ever 

 seen from the Potomac was taken in the vicinity of the White House in the mouth of November. 

 In the season of 1880, I believe, several full-grown Shad were taken below Holyoke Dam on the 

 Connecticut River in the latter part of the summer. These instances would seem to indicate that 

 under certain conditions the Shad may remain in our rivers during the whole season. 



The appearance of the spent fish, or those which have deposited their eggs, enables the fisher- 

 men to recognize them at once, and various names have been given to them. From the fact that 

 they are supposed to be moving down the stream when taken, they are called "Down-runners," 

 and from their lean, slim appearance, they are also called " Racers." 



The Shad make their first appearance in the Saint John's River about the middle of Novem- 

 ber, the height of their spawning season in that river being about the 1st of April. In the 

 Savannah River they appear early in January, and in the Neuse River at a period not much later 

 than in the Savannah. In the Albemarle the important Shad seine-fisheries begin early in March, 

 but doubtless the fish are in the Sound some time before that date; not, however, in numbers 

 sufficient to justify the great expenses attendant upon the pperation of these large seines. In the 

 Chesapeake Bay they make their appearance in February, although the height of the fishing 

 season in its waters is during April and May, and at a date somewhat later in the more northern 

 tributaries. In the Delaware, Connecticut, Merrimac, and Saint John (Nova Scotia) Rivers, Shad 

 are first seen at periods successively later as we proceed farther north. The date of their first 

 appearance in any of these waters, however, varies from season to season, the limit of such varia- 

 tion being from three to four weeks. 



These irregularities in the time of the run into our rivers, which cause so much perplexity 

 and discouragement to the fishermen, are, however, readily explained when we keep in view what 



