o2 UEPOKT OF COMMISSIONER OF FISH AND FISHERIES. 



Mr. Greeu and Mr. Wilmot both procured eggs this season from the 

 Detroit Eiver. Mr. Green made use of a newly-devised apparatus for 

 hatching, that proved to be a most exceUent contrivance, both for the 

 economy of space and the facility for earing for the eggs. By this 

 method he will be enabled to hatch five or six times the quantity of eggs 

 in the same building. The young tishes were distributed in accordance 

 with the excellent plan adopted by the New York commissioners for 

 supplying demands from all parts of the State, without expense, on ap- 

 plication. 



The success attained by these persevering experiments is now com- 

 plete, and the white-tish may be restored by artiticial propagation, to 

 the same extent as the salmon, or the brook-trout, or the shad. As has 

 been shown, the white-fish has advantages in this particular that the 

 other species have not. The obstruction of streams is no obstacle in tbe 

 way of their multiplication, because they have no necessity of ascend- 

 ing them, and, unlike the trout and the salmon, they cannot be suspected 

 of eating each other. 



Attempts at feeding the young fishes have all been failures, and the 

 only natural food that has been found in their intestines is the species 

 of DiatomacciV reported by Mr, Briggs. But as they are more vigor- 

 ous and strong in the earlier stages of growth, there is not the same ne- 

 cessity of caring for them until they are partly grown, and they should 

 be put into the waters they are to inhabit soon after the ovisac is ab- 

 sorbed, and allowed to find their natural food for themselves, just as the 

 young shad are treated when hatched artificially. 



Artificial propagation afibrds advantages that compensate for all the 

 overfishing and losses that the fish-faun;e suftor from man and natural 

 causes. The great numbers of eggs found in the ovaries of fishes in 

 reality aftbrd little evidence of their capacity for popnlating the waters. 



It is a fact, illustrated in nearly if not all branches of the animal 

 kingdom, that the most fecund species do not, by any means, increase 

 the fastest in numbers, but fitom the greater evils they are subject to, 

 and the greater number of enemies they encounter, there is such a 

 fatality during the earlier stages of growth that the losses balance the 

 numbers produced, and less fecund species, by being better protected, 

 equal them in numbers. 



The most perfect illustrations of this fiict may be found among our 

 lake-fishes. The muskellunge. Uso.v uohilior, has a very large number of 

 eggs. A cast of the ovaries of a large female specimen, made by Dr. E. 

 Sterling, of Cleveland, Ohio, is in the possession of the Smithsonian 

 Institution. The ovaries measure over two feet in length, and the eggs 

 are about the same diameter as those of the white-fish: they contain 

 at least five times as many eggs as a pound white-fish, and yet, as 

 regards numbers, the muskellunge is a comparatively rare fish. There 

 are, undoubtedly, exigencies attending the egg-stage of this fish that 

 will account for this fact. 



In the case of the white-fishes, though annually depositing millions 



