ARTIFICIAL PROPAGATION" OF SHAD 467 



nally becoming more and more numerous. The mature eggs are 

 finally freed from the remainder of the ovary and extrusion begins, 

 a liquid stream of eggs and mucus flowing from the oviduct on the 

 sliglitest pressure of the abdomen. 



Freshly deposited shad eggs are of a pale amber or pink color, and 

 are transparent. They are about -jif inch in diameter and somewhat 

 flattened and irreguhirly rounded in form. The egg membrane is 

 much wrinkled and lies in close contact with the contained vitcllus. 

 Immediately after fertihzation the egg becomes spherical through 

 the absorption of water and apparently gains very much in bulk, 

 measuring about V7 of an inch in diameter; but this gain is only the 

 distended eg^ membrane, the vitelhis or true germinal and nutritive 

 portion not haAnng increased. The vitellus is heavier than water, 

 and a large space filled with fluid now exists between it and the mem- 

 brane, the vitellus rolling about and changing its position as the po- 

 sition of the egg membrane is altered. No adhesive material is 

 found on the outside of the membrane, though when fii'st extruded 

 the eggs are covered with a somewhat sticky ovarian mucus. 



In a state of nature the shad deposits its eggs loosely in the rivers 

 without building a nest, the two sexes running along together from 

 the channel toward the shore and the eggs and milt being ejected 

 simultaneously. On quiet evenings, at the height of the season, 

 spawning shad may be heard surging and plunging along the shores. 

 By fishermen this is termed "washing." 



Shad are prolific, but much less so than many other food fishes. 

 The quantities of eggs taken by spawn takers do not represent the 

 actual fecundity, for many are cast in advance of stripping. The 

 average number is not more than 30,000. Single fish have been kno^vn 

 to yield 60,000, 80,000, 100,000, and 115,000 eggs, and on the Dela- 

 ware River, in 1885, one yielded 156,000. Many eggs fail to be fer- 

 tilized, and but a comparatively small percentage of those impreg- 

 nated are hatched. After being extruded the eggs sink to the bottom, 

 where they remain imtil hatched subject to the attacks of fish and 

 other water animals. Eels are very destructive to shad spawn and 

 often attack shad caught in gill nets, devouring the undeposited eggs 

 and sometimes mutilating half the catch of a gill-net fisherman. 



The development of fungus is one of the greatest dangers to shad 

 eggs in a natural state, and another potent agency for their destruc- 

 tion is the mud brought down by heavy rains, Wrying and suffocating 

 the eggs. 



After spawning, shad are denominated "down-runners," "racers," 

 and "spent fish." They are then very lean and hardly fit for food, but 

 they soon begin to feed and have become fatter by the time they 

 reach salt water in the summer or fall. 



YOUNG SHAD 



In the Middle Atlantic States the young fish remain in the rivers 

 mitil the cool weather of fall comes; then they begin to di'op dowTi- 

 stream, and by the last of November have passed out into the oceans 

 or bays and are lost sight of until they come back, 3 or 4 years later, 

 full-gro^Ti and ready to spawn. They leave the Potomac River 

 when the water falls to about 40°, by which time they are about 3 

 inches long. They have been observed in great abundance about 



