REPORT OF THE COMMISSIONER OF FISHERIES. 25 



species, which, when itself enmeshed, so tears the twine with its teeth 

 and abrades it with its rough scales as to ruin the nets. It is esti 

 mated that in 190-1 the loss in catch and gear from this cause amounted 

 to $10,000 in Boston Bay alone, and the destruction extends in even 

 greater measure northward. The damage has vastly increased in 

 recent years. 



The most practicable way to hold these destructive fishes in check 

 would be to make them of commercial value. Although they have 

 fewer enemies than most fishes, on the other hand they do not breed 

 so rapidly, and if a market for them were created it would not be long 

 until their numbers would decrease. This species offer commercial 

 possibilities, of which some are suggested: (1) The skin makes a good 

 polishing leather for metals and hard wood; it is used for this purpose 

 by cabinetmakers in many parts of Europe. (2) The liver, at least of 

 the horned dogfish, when boiled down into oil gives a fair yield, but 

 at present the price of dogfish livers is too low to make this business 

 pay. (3) The fins yield a considerable amount of glue; by simple boil- 

 ing a fair quality was extracted. (4) The flesh is a wholesome food, 

 and is eaten in Europe and elsewhere; it is free from bones, and when 

 cooked it is of delicate texture, somewhat dry, with a good flavor, 

 resembling halibut, but more delicate 



STUDIES OF SMALL LAKES. 



( \>iut, client lakes and neighboring waters. — In pursuance of the plan 

 of the Bureau to undertake biological investigations of the principal 

 waters of each of the large river basins of New England, the Connecti- 

 cut lakes and neighboring waters in northern New Hampshire have 

 been examined with special reference to the habits and distribution of 

 the fishes. Sixteen species of fishes were ascertained to be indige- 

 nous to these waters, and 5 other species had been introduced, but of 

 the latter only the landlocked salmon and the European brown trout 

 are known to have survived. Apparently these lakes are w r ell suited 

 in every way to trout, lake trout, and landlocked salmon, having fairly 

 deep, cool water and plenty of small fish to serve as food. 



Lakes of northern Indiana. — The study of the lakes of northern 

 Indiana was continued, the principal line of investigation pertaining 

 to the aquatic plants and their relation to the fish life. Each of is 

 small lakes in the region was examined with reference to the species 

 of aquatic plants growing therein, the depths in which each species 

 grows, the relations of each to the fish food, and the character of the 

 bottom. Lake Maxinkuckee, Which had been previous!}' studied more 

 thoroughly, was used as a standard with which to compare the condi- 

 tions in other lakes. The general biology of Lake Maxinkuckee was 

 studied during the fall and winter, special attention being given to the 

 food of the different species of fishes at that season of the year. The 



