678 HISTORY AND METHODS OF THE FISHERIES. 



Some of these materials were sufficiently water-soaked to sink at once to the bottom ; others floated 

 many miles, some of the coarser sorts even to the open sea; but sooner or later all of the sawdust 

 and a great part of the other refuse sank to the bottom. The coarse and heavy portions resisted 

 the action of the currents much more than the sawdust alone could have done, and the interstices 

 being filled with sawdust and mud, deposits were thus formed that after the lapse of years came 

 even to obstruct navigation. 



The degree to which the fisheries are affected by this refuse is not easily determined. So long 

 as it remains in suspension it does not seem to deter fish from ascending a river, though swimming 

 thickly in all the strata of the water from the surface to the bottom. Where it settles to the bot- 

 tom, however, it undoubtedly destroys all those animals that find their home in the sand and gravel 

 and mud of the natural bottom, and to that extent deprives young fishes of their natural food. It 

 is not unlikely that this may have had much to do with the disappearance of shad and bass from 

 some localities. 



Of a more serious character are the changes resulting from the erection of dams. Almost 

 every stream in the populated parts of the State large enough to turn a saw-mill has been thus 

 obstructed at from one to a dozen points in its course. The dams were with scarcely an exception 

 built in utter disregard of their effect upon the fish, and in the majority of cases no adequate fish- 

 ways were provided. The breeding grounds of salmon, shad, and alewives were therefore greatly 

 curtailed in all the rivers, while in others they were entirely cut off. For example, in the Kennebec 

 River the building of the dam at Augusta in 1837 completed a chain of obstructions that reduced 

 the range of shad in that river and its tributaries from 150 to 50 miles, and that of salmon from 

 about 300 to 50 miles. These figures do not, however, represent the injury done to those fisheries, 

 which is measured rather by the reduction of the area of spawning-ground. This, in the case of the 

 salmon, was from perhaps 50 miles of rapids to less than half a mile, and in the case of shad from 

 100 miles of gently flowing water to about 25 miles. It would be difficult to arrive at an exact 

 estimate of the amount of the injury thus .done, but I deem it safely within bounds to estimate the 

 diminution of the productive capacity of the rivers at 90 per cent, from this cause alone. 



The revival of interest in the river fisheries, which began in Maine in 1867, has given rise to 

 renewed efforts to facilitate the passage of fish up the rivers. Improved forms of fish- ways have 

 been devised and constructed in many places, yet but a small proportion of the waters affected 

 have been as yet reopened. 



3. NATURAL AND ECONOMIC HISTORY OF THE RIVER FISHES. 



LIST OP SPECIES. The river fisheries of Maine aim at the capture of the following species : 

 Salmon (Salmo salar), shad (Glupea sapidissima), alewife (Clupea vernalis), smelt (Osmerus mordax), 

 striped bass (Boccus lineatus), eel (Anguilla rostrata), torn-cod (Microgadus tomcod), and sturgeon 

 (Acipenser sturio). The blueback alewife (Clupea astivalis) is also caught to some extent in the 

 weirs that are built for the true alewife, and in some cases the two are confounded. White perch 

 (Roccus americanm) are rarely taken, this species being in Maine mostly confined to the non-tidal 

 fresh waters. As a neglected species may be mentioned the lamprey, which occurs in nearly or 

 quite every river, but is rarely utilized in any way. 



THE SALMON (SALMO SAL AH). 



NATURAL HISTOBY. The salmon of Maine (Salmo salar) is identical with the salmon of all 

 the rivers of Eastern North America and Europe. A brief statement of the principal points 

 in its natural history will suffice. It outers tlio rivers in the spring and summer, beginning and 



