48 



some places, e.g., Assawompsett Pond, it has not been seriously 

 impaired. While we deplore the injury to the fishery, we must 

 consider the problem from a broad point of view, and remember 

 that these ponds have been put to a more universal use. 



Obstructions. 



The first step in the development of a fishery is the removal 

 of all obstructions in order to give free passage to the spawning 

 grounds. Natural changes may alter the course of flow, as 

 the change in the outlet of North River by the gale of 1898. 

 Less extensive changes, mostly artificial, have occurred in other 

 streams, which have had more or less effect upon the migra- 

 tion of the alewife. Natural or artificial falls, dams, unless 

 equipped with fishways, and material of various kinds prevent 

 or make difficult the passage of alewives. 



Materia 1 . — Wire or wooden fences, rubbish and old ruins 

 which have been placed or have fallen into the stream are the 

 most common form of artificial obstructions, e.g., Chebacco 

 Brook (Fig. 8). Luxuriant vegetation may completely or par- 

 tially choke a stream, e.g., wild rice in Herring River, Wellfleet 

 (Fig. 6). In certain localities the natural bed of the stream 

 has been so altered by dredging or narrowing that the incline 

 has become too steep and the flow too rapid for the easy pas- 

 sage of the fish. Narrowing the stream by drainpipes of in- 

 sufficient diameter for the volume of flow may bring about 

 well-nigh impassable conditions. The private screening of any 

 alewife stream for duck raising or other purpose should not 

 be permitted unless sufficient space is left for the passage of 

 the fish. 



Dams. — Dams are the inevitable result of the inroads of 

 colonization following the waterways. In former days water 

 power was even a greater necessity than in the present era of 

 coal, gas and electricity. As manufacturing became of greater 

 moment more power was required, and eventually numerous 

 dams were erected on the streams of Massachusetts. Following 

 the early settlements the coastal streams were first affected, 

 and in the old laws can be traced the inevitable conflict between 

 fishery and manufacturing interests, with the balance of power 

 resting with the latter. 



