458 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



to their spawDiug-grounds, and from these puny parents nought but 

 small puny offspring pan be propagated. 



The cause of decrease in the number of fishes taken can, I think, be 

 placed uuder the following heads : 



1. Erection of insurmountable dams: 2. Destruction of young fry: 

 3. Destruction of seed-fishes: 4. Destruction of spawn, 



(3 a.) Erection of dams. — The erection of an insurmountable dam, cut- 

 ting off parent fish from their wonted spawning-grounds, has been fre- 

 quently followed by the total disappearance of the fishes from even the 

 lower reaches of the river. A notable example of this took place upon 

 the erection of the dam at Fairmount, Philadelphia. Before this large 

 numbers of shad were taken in the reach of the river between the falls 

 and its mouth. In a few years they had utterly vanished. 



I am aware that it is the general belief that the fishes were driven 

 away by the coal-tar thrown into the river from the city gas-works, but 

 careful investigation has shown that shad-fishing was extinct several 

 years previous to the constrnction of the gas-works. 



A fish-way, capable of carrying shad, has long been a desideratum. 

 Great hopes are entertained of the capabilities of that recently erected 

 by Mr. Brackett at Holyoke, but the matter is still but an exi)eriment. 



Shad are taken in large numbers directly below the LackawaxenDam 

 upon the Delaware; but few, if any, ascend beyond this point. How- 

 ever, in this case there are ample spawning-grounds below. Should any 

 of the new jilans for fish-ways now before the public prove a success the 

 removal of these impediments is but a work of time. 



(3 b.) Destruction of fry. — Few persons have any idea of the immense 

 quantity of young fishes destroyed on their way to the sea. In our more 

 northern rivers, with which I am best acquainted, the number devoured 

 by carnivorous fishes is enormous. In 1870 a large number of young 

 rock-fishes were examined, and in every case young shad were found in 

 their stomachs. From one fish, eighteen inches in length, seven young 

 shad were taken. 



Fish-baskets destroy millions. In 1871 I made a careful and thorough 

 examination of the upper waters of the Delaware River, for the purpose 

 of investigating this point. The fticts elucidated were astounding. It 

 was ascertained that a scoop-shovel, with which to shovel out the dead 

 young shad which accumulated in the basket, was an important part of 

 the fishermen's equipment. One proprietor acknowledged that as much 

 as a two-horse load of dead young shad had been shoveled from his bas- 

 ket during a single day. I am happy to state that through the active 

 exertions of the fish-police these engines of destruction have entirely dis- 

 appeared from the River Delaware, and I believe also from the Susque- 

 hanna, though they still abound in the more southern streams. The 

 good effect of their destruction in the Delaware is already shown by the 

 fact that the number of young shad seen descending that river during 

 the past autum n has been far greater than ever previously noticed. Wing-' 



