75 



Merrimack River. 



The Merrimack River, with its tributaries, forms the princi- 

 pal drainage system of northeastern Massachusetts. The 

 greater part of its course lies in New Hampshire, and of that 

 portion in Massachusetts, the lower part is tidal water. At 

 the present time dams, sewage and trade-waste pollution render 

 it unfit for the passage of salmon, shad and alewives, which 

 formerly frequented the river in great abundance. In Massa- 

 chusetts the two principal obstructions have been the dams at 

 Lawrence and Lowell, both of which were equipped formerly 

 with fishways in the form of parallel lines of tanks. 



Subsequent to 1876 a serious decline occurred in this public 

 fishery, in spite of voluminous legislative enactments, and, at 

 the present time, with the exception of seining at the mouth, 

 the Merrimack River furnishes no alewife fishery. The causes 

 bringing about this condition were the practically impassable 



