REPORT OF COMMISSIONER OF FISH AND FISHERIES. xlv 



this reason it is that the action of State or gen-eral governments in regard 

 to the multiplication of salmon and -other auadromous fish may even be 

 carried on without any reference wliatever to the existence of dams ; and 

 as far as the general interests of the community are concerned, it per- 

 haps may be in many cases much cheaper to continue the artificial fertil- 

 ization anddevelojjment of theeggs, andtheplantingof theyoungin suit- 

 able waters, than to require the inconvenience and expense of removing 

 artificial or natural obstructions or of inserting, costly fish- ways. After 

 the preliminary stages have been performed, the expenditure of a few 

 hundred dollars a year will be sufficient to insure the presence of many 

 thousands of shad and salmon in the lower waters of a given stream. 

 Of course, to provide for the natural multiplication of the species and 

 their equal division throughout the entire valley of the stream, the 

 dams or obstructions must be regulated as already referred to. 



19. — TREATMENT OF CERTAIN SPECIES. 



The hatching of shad. 



The boxes most generally in use at the present time for shad-hatching 

 we owe to the ingenuity of Mr. Seth Green, and their introduction con- 

 stituted an era in the art of pisciculture. The ordinary methods for the 

 development of fish-eggs would not answer the purpose for the shad, 

 and all attempts at hatching in the regular establishments would be 

 practically a failure in consequence of the comparatively small number 

 that could be managed by the usual methods, while an immense aggre- 

 gate is required to produce even a moderate effect upon the supply in a 

 stream. 



The idea of a floating box is by no means new, such instruments 

 having been used in Europe for many years, especially for hatching out 

 the eggs of the Cyprinidw, which adhere to whatever they touch, and re- 

 quire cnreful treatment. Mr. Millet used floating boxes in 1853 for hatch- 

 ing trout and salmon. The difficulty in hatching shad existed in the fact 

 that when the boxes floated in the water so that the bottoms were hori- 

 zontal, the proper circulation inside of the box was not established, and 

 the eggs would spoil when exposed to the heat of the sun in consequence 

 of their crowded condition. By the simple expedient of nailing two 

 strips of board scantling parallel to each other, one on each side of the 

 box, at an angle inclined to the bottom, the boxes are made to float 

 obliquely in the water, since the strips themselves floated horizontally, 

 and caused the bottom to be tilted up. The boxes are anchored with 

 the inclination up stream, so that the current of water, striking freely 

 against the inclined face of the wire gauze, which constitutes the bot- 

 tom of the box, passes through it with a constant flow, producing the 

 necessary motion in the eggs. By means of this device it has become 

 possible to hatch shad by millions, where results would necessarily 

 have been limited to thousands. 



