RANGELEY LAKES, MAINE: FISHES, ANGLING, AND FISH CULTURE. 587 



it apparently is unsteady and dependent upon a continuous readjustment by fish 

 culture. The salmon has become the dominant species and, therefore, the most exten- 

 sive and intensive influence. It has spread throughout the chain of lakes, even into 

 the Androscoggin River. In Umbagog Lake, however, it probably exists to a limited 

 extent only through the favor of the two deep holes. The salmon is the most powerful 

 competitor in the food supply of the trout, as their all-of-the-year habitats are identical 

 and they subsist upon the same kind of food, and the salmon, possibly, to some extent 

 upon the trout. The trout supply evidently requires the aid and advantage of artificial 

 propagation. 



The pickerel has been restricted in its effects to Umbagog Lake, where it has never 

 suffered from the lack of sufficient food and where it has not been to any extent depend- 

 ent upon the trout. On the whole, it has found a congenial habitat in the lake, but has 

 been subject to occasional mysterious mortal epidemics. A possible, if not to say 

 probable, explanation may be found in the existing conditions partly produced by 

 artificial modifications of the biological conditions. The lake being long and narrow, 

 with its longest axis lying north and south and out of the direction of the prevailing 

 winds at the time, receives a comparatively small amount of oxygenation from wind 

 and wave action. The death of a great quantity of plant and plankton organisms, both 

 resident and inflowing, might result in a greater amount of decomposition accompanied 

 by an excessive amount of carbon dioxide. Furthermore a large amount of plank- 

 ton is usually associated with high carbon-dioxide and low oxygen contents. An 

 obstructed outlet would produce an increased amount of plankton, and an obstructed 

 inlet would, perhaps, produce a temporary partial stagnation. Carbon dioxide is very 

 toxic to fishes, but some fishes are less affected by it than others. The carbon dioxide 

 content is usually highest in April and June. The early epidemic previously men- 

 tioned apparently occurred soon after the lake was free from ice, probably some time 

 in May. The epidemic of 191 2 occurred in the last of May and first of June, when, 

 it is stated, the dams of the outlet and inlet had been for some time closed for storage 

 purposes. While the cold of winter and early spring would retard decomposition, 

 the surface ice would, on the other hand, prevent oxygenation from winds and wave 

 action. An inspection of the map of Umbagog Lake will perhaps show that its general 

 shape and the location of the main inlet and the outlet would support this idea. 



Smelts have increased in number and have spread throughout the chain, even 

 occurring in Umbagog Lake. They are of undoubted value as food for the salmon 

 and trout, in which they have supplanted the blueback trout, and in that direction are 

 of no little importance to the inhabitants of the region, as indicated by the following 

 quotation from Maine Woods, May i, 1913 : 



The smelts began running in Kennebago Stream last Thursday night (Apr. 24), and much sport 

 among the residents is being enjoyed. "Going smelting to-night?" is the form of greeting heard from 

 young and old, and if you don't reply "You bet I am," you are no sport, for when the smelts start up 

 Kennebago Stream the whole town turns out to meet them, for they are the first fish of the season, and 

 when salt cod and herring have been the fish course all winter they certainly do taste good. From 

 Indian Rock to a goodly distance upstream one can see tlie glint of lantern and small fires, where groups 

 of men and boys are gathered, dipping smelts from the stream to pails, boxes, and grain sacks. 



