Belding. — Preservation of the Alewife 99 



directing them. Screening the stream with an iron grating is a 

 successful though expensive method. A submerged stone barrier 

 leading to the fishway entrance has proved at times effective. 



(3) Construction. — The nature of the soil and height of the 

 dam largely influence the difficulty and expense of construction. 



(4) Destruction. — Destruction of a fishway by spring floods 

 may be partially avoided by building a concrete structure, locating 

 the fishway where it is subject to the least damage, and having 

 part or all removable when not in use. 



Standard Fishway s. — A successful fishway which will take all 

 species of anadramous fish has never been invented. In our work 

 two types of fish ways have been designed, and have proved highly 

 satisfactory for the alewife streams. No claim is made that these 

 are the long sought universal fishway s, or that they are suited for 

 other species of fish. We know that they are successful for ale- 

 wives, and that their simple type makes them well adapted to 

 Massachusetts streams. 



It was early realized that the main difficulty lay not in the 

 fishway itself, but its adaptation to various prevailing condi- 

 tions. Two distinct standard types which can be adapted to all 

 ordinary dams have been designed. 



The first type, The David Fishway, may be either of concrete 

 or wood construction. With its sloping bottom and irregular 

 baffles it resembles the Brackett type, but possesses the additional 

 qualifications of frequent rest pockets, and a steady, uniform flow 

 of water, which is controlled by the upper gate. Although more 

 expensive than the second standard type, it can be advantageously 

 installed in a limited space over an irregular course. 



The second type, The Straight Run Fishway, is especially 

 adapted for low dams where the contour of the stream bed affords 

 a gradual fall. This primitive form of fishway more nearly resem- 

 bles a natural swiftly broken stream, and possesses the advantage 

 of stimulating the rapid ascent of the ale wives. 



Dam owners are required by law, when requested by the Fish 

 and Game Commission, which furnishes complete plans and spec- 

 ifications for every fishway, to install suitable fish ways at their 

 own expense, and keep them open at specified times, under penalty 

 of a fine of $50.00 per day for non-compliance. In spite of the dif- 

 ficulty in obtaining the willing co-operation of the dam owners, 



