LVI REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Removal of ohstructions to the movements of fish and of injurious engines 

 of capture. — A third method of favoring the natural increase of fish 

 consists in removing the natural or artificial obstructions to the ascent 

 of the fisli from the lower to the higher waters of a stream, or their de- 

 scent in the opposite direction. Spawning fish, notably the shad, the 

 fresh-water herring, and the salmon, enter the mouths of rivers from 

 the sea at the appointed time and find their spawning ground at various 

 points on the river, the herring low down, the shad in the medium dis- 

 tricts, and the salmon more toward the head. The interposition of arti- 

 ficial dams, unsurmountable by the fish, has been a great and i)erhaps 

 the chief factor in diminishing the supply in this class of fish, as with 

 the erection of a dam, especially near the mouth of a stream, the 

 spawning fish ascending are arrested, and are either turned back 

 from their course or else fail to find a suitable place or opportunity to 

 deposit fertilized eggs. For the first two or three years there will be a 

 continually lessening of the run of the fish. At the end of this time, 

 however, or when all the fish born in that stream have been caught 

 or destroyed, the run ceases, and after that, even though the obstruc- 

 tion be removed, the river will remain practically barren of fish until re- 

 stocked by human agencies. 



Again, even in many cases where the adult fish succeed by their own 

 efforts, or by the use of fishways, in getting to the headwaters of the 

 rivers, the progeny is destroyed in enormous quantity by the so-called 

 fish-baskets or weirs, which take the young by myriads. The most 

 potent agents in this respect are the eel traps or dams, which consist 

 for the most part of two converging lines of stone walls, with the 

 apex pointing downwards, and ending in a so-called fish basket. Here 

 eels, upon their descent to the salt water, are taken in great quantities, 

 and with them the young of shad, salmon, bass, etc. 



It may safely be stated that nothing has done more to diminish the 

 number of adult fish, and prevent their increase in our waters, than 

 this engine of destruction. IS'othing short of absolute removal and pro- 

 hibition of such " fish-baskets" will answer the purpose; although, of 

 course, such prohibition will interfere with the take of the much desired 

 eels. Still the interests of an entire community should be considered 

 l^aramount to those of a few farmers living near the streams in question. 

 The other obstructions, whether natural or artificial, constitute a factor 

 in some instances greater than the fish-baskets, and sometimes less. 

 There are many streams, such as the Susquehanna and the Delaware, 

 where the parent or spawning fish can, under favorable circumstances, 

 make the ascent and deposit their eggs — the young fry, however, to be 

 caught by the fish-baskets. In other cases, where the passage upward 

 is barred by the obstruction in question, the fish-baskets are of less im- 

 portance, as being confined in their action to a smaller number of spe- 

 cies. The young eels coming up from the ocean in the spring, can make 



