586 BULLETIN OF THE BUREAU OF FISHERIES. 



react to disturbing influences. Molechunkamunk and Wellekennebacook, although 

 smaller than Mooselucraaguntic, probably compensate for their loss through the outlet 

 by the benefit they receive from the upper waters. Therefore, if exact data were available 

 it would, perhaps, show little difference from Mooselucmaguntic save in quantity and 

 would be no more appreciably affected by a general disturbance of the whole chain. 



Umbagog has a greater area than Oquossoc or the last two lakes mentioned, but 

 it is generally much shallower and is otherwise of a very different character. Its faunal 

 contributive resources are much more extensive than all of the other lakes together. But 

 owing to the widely different prevailing conditions, some forms of life continue to exist 

 only through tolerance, and are, therefore, in unstable equilibrium and subject to 

 serious disturbances from slight causes. Some of the forms could not at all times 

 tolerate the general conditions were there not ameliorating factors. The ameliorating 

 conditions being restricted, these tolerant forms are necessarily limited in number and 

 are, therefore, more easily exterminated. The stock of such forms depends largely 

 upon renewals from contributive waters. 



The deficient general data respecting the distribution of the fishes in the Rangeley 

 Lakes prevent reaching very definite conclusions regarding their source and manner of 

 origin, as well as their ecological importance, past and present, but the few known 

 facts are suggestive. A knowledge of the source and manner of the origin of the fish 

 fauna is not particularly pertinent to a discussion of present-day conditions, but it 

 may be briefly stated that probably the majority of the species gained access during a 

 period of a lower level of the land and relatively higher stages of water and are mostly 

 of northern derivation, perhaps by way of what is now the Kennebec Basin. The 

 fish fauna of the Rangeley Lakes shows a contributory but not much if any recipient 

 relationship to the Androscoggin River, from the fact that most of the Rangeley Lakes 

 species are those of common distribution and are found in the river, while others of 

 common distribution occurring in the river are not found in the lakes. 



Of 39 species of fresh-water fishes recorded from Maine, New Hampshire, and 

 Vermont, 35 of which are known from Maine, only 13, or just one-third, were apparently 

 indigenous to the Rangeley Lakes Basin above the Androscoggin River. One of these 

 was for a long time considered as peculiar to the Rangeley Lakes and restricted to two 

 of them. Twenty-one of the Maine fishes are very common in certain regions of the 

 State, and 13 are of general distribution throughout the State. The fauna was thus 

 to some extent unique but of concentrated quality, as it were. There were only two 

 species of food fishes and only one of these a game fish. All but one of the remainder 

 of the fishes that were at all common served as food for this one game fish, some of 

 them as a continuous supply, the rest at least as a seasonal or temporary resource. 

 Thus, one game fish levied more or less upon 1 1 different species. Some of these recip- 

 rocated or retaliated to some extent by attacking the game fish at some stage of its 

 existence, but their principal food consisted of smaller animal life, for which all species 

 competed. 



The biological oscillations produced by modifications of the physical conditions 

 have been amplified by the introduction of competitive and destructive factors, result- 

 ing in changes in the fauna. Among the fishes, instead of the 12 or 13 original species, 

 there are now 16 or 17, at least one, or perhaps two, of the original forms having been 

 replaced by new ones. There is, perhaps, an approach to a readjusted balance, but 



