CATALOGUE OF VERTEBRATES 685 



ward associated with it. It enters the various creeks and many 

 thousands are occasionally taken by nets, in the creeks they have 

 overstocked." 

 C. aestivalis, Mitch. [A. cyanonoton, Stor.) Glut Herring. Blueback. 



Like preceding, but with lower fins and smaller eyes ; has 

 peritoneum black ; of less value as a food fish ; appears later 

 than C. vernalis. 

 C. sapidissima, Wils. [Alosa, prxstabilis, De K.) Common Shad. 



Bluish above ; sides silvery ; a dark spot behind opercle, and 

 sometimes others along line dividing the darker back from the 

 sides ; body deep ; mouth large, jaws equal, the lower fits into 

 notch of upper ; cheeks much deeper than long ; fins small ; 

 dorsal nearer snout than base of caudal ; no teeth (except a few 

 on jaws, deciduous) ; preopercle scarcely prolonged anteriorly 

 below. Dorsal rays, 15; anal rays, 21 ; ventral scutes, 21 + 16. 



" The principal shad river in our State is the Delaware, and 

 in this stream they are not now as abundant, nor met with as 

 large as twenty years ago. Many causes have been suggested 

 for the decrease in the yield, and the destruction of the fishery 

 by the erection of dams has been discussed in all its bearings. 

 The diminution of their numbers is dependent, in all probability, 

 upon the marked increase of rockfish, which devour in immense 

 numbers the young shad that in September descend the river to 

 seek winter quarters in the ocean. The attacks of the rockfish 

 also will explain, in a measure, the scarcity of the large speci- 

 mens occasionally taken, and known as ' brass-backs.' 



" The erection of dams above Trenton would not destroy the 

 fisheries if such dams were erected with a ' fish-way ' that would 

 enable them to pass up stream, without necessitating them to 

 make an actual leap, which the salmon considers no objection. 



" The diminution of the annual catch of shad may also be 

 explained by the prevalence of immense gill-nets in the lower 

 part of the river, which are occasionally so numerous and so 

 completely across the river that it is impossible for any shad to 

 pass them. 



" Shad spawn about the ' falls ' opposite Trenton, more or less 

 frequently, every summer, but the ova are probably always 

 devoured by the swarms of rockfish and white perch that are 

 ever on the alert for the eggs or the young. The shad appears 



