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 begau 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 ECONOMIO HISTORY OF THE RIVER FISHES. 
List OF SPEOIES.—The river fisheries of Maine aim at the capture of the following species: 
Salmon (Salmo salar), shad (Clupea sapidissima), alewife (Clupea vernalis), smelt (Osmerus mordac), 
striped bass (Roccus lineatus), eel (Anguilla rostrata), tom-cod (Microgadus tomcod), and sturgeon 
(Acipenser sturio). The blueback alewife (Clupea estivalis) 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 
(Roceus americanus) are rarely taken, this species being in Maine mostly confined to the non-tidal 
fresh waters. Asa 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 SALAR), 
" NATURAL HISTORY.—The salmon of Maine (Salmo salar) is identical with the salmon of alt 
the rivers of Eastern North America and Europe. A brief statement of the principal points 
in its natural history will suffice. It enters the rivers in the spring and summer, beginning and 
