584 



BULLETIN OF THE BUREAU OF FISHERIES. 



There is one assignable cause that applies to both the disappearance of trout and 

 reduction in numbers and size of the pickerel, and that is man. He seeks the larger 

 fish, he seeks numbers, and often at a time when the largest numbers of large fish can be 

 obtained, that is, during the winter by fishing through the ice, when pickerel are hungry 

 and its natural food has concealed itself in the mud or amongst the water plants and 

 moves but little or not at all. Ice fishing is one of the most potent causes of the depletion 

 of northern lakes, especially small lakes like Umbagog, of their food fishes, and there can 

 be little doubt that by this means, augmented by annual plug fishing in their limited 

 summer resorts, the trout of Umbagog Lake have been diminished so greatly in numbers. 



miller's thumb (Cottus gracilis). 



The miller's thumb is a fresh-water sculpin. The only vernacular names that 

 seem to be applied to it in Maine are brook cusk and rock cusk. It is sometimes mis- 

 taken for young cusk. Lota maculosa, which does not occur in the Rangeley Lakes. This 

 species is apparently the only one in New England fresh waters, disregarding, possibly, 

 the Lake Champlain and St. Lawrence drainage, but it is very common almost every- 

 where, especially in northern waters. In some places, however, it has become greatly 

 reduced in numbers by other fishes feeding upon it. On the other hand, it is very 



Fig. 23. — Miller's thumb {Cottus frracilis). 



destructive to the eggs of such species as spawn where it occurs. The only record of its 

 occurrence in the Rangeley Lakes is that of specimens in the museum of the Boston 

 Society of Natural History, collected by Prof. F. W. Putnam many years ago, and the 

 statement of Mr. Haines, of Rangeley, that it is often found in trout stomachs. 



It attains at least 4X inches in length. Large individuals, up to 4 inches long, 

 however, occur in the Androscoggin River, and the writer has examined specimens 

 from Bear River in North Newry. (See Table XI, p. 594.) 



The coloration of the different individuals varied somewhat, but in general the 

 body was gray with reddish tinge above, speckled with darker gray, and with traces of 

 five dusky crossbars, of which only the one under the posterior part of dorsal extends 

 fully across the body; spinous dorsal margined with reddish and broad dusky strip 

 through the middle; soft dorsal, pectoral, and caudal finely barred with black. 



SUMMARY. 



Immediately before the advent of white men the conditions of the lakes were 

 much different from those of the present time. They had a smaller area, lower level, 

 and much less volume. Their intercommunications were unrestricted except by 



