534 NATURAL HISTORY OF AQUATIC ANIMALS. 



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 

 iis many eggs as a pound White-fish, and yet, as regards numbers, the muskellunge is a compara- 

 tively 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 of eggs, the delicate 

 nature of the embryo, and the numerous spawn -eaters, effect a certain balance of numbers with 

 relation to the general faunse of the lakes, so that, up to the time of the early settlement of the 

 Lake region, the fish were found in great abundance. The nets now came in as an additional agent 

 in preventing the increase, the pound-net, particularly, killing a large percentage of the fishes that 

 had not matured sufficiently to assist the increase by depositing Spawn, and in consequence the 

 numbers of fishes were rapidly reduced. 



"The care of the eggs in the hatching troughs has proved, beyond question, the frail nature 

 of the eggs of the White-fish. They are smaller, and have a. much thinner investing membrane, or 

 shell, and have not the same enduring vitality that the ova of the Trout and Salmon have. So that 

 in the open water of the lakes and rivers by far the greater number are lost because of the 

 disturbance of the bottom by the autumn storms and the deposit of sediment from the muddy 

 water, the failure of many of the eggs to come in contact with the milt of the male fish, the 

 myriads devoured by the army of spawn-eaters, and the additional evils of pollution of the waters 

 from the drainage of cities, manufactories, and saw-mills, and the dragging of seines over the 

 spawning beds. 



"A quantity of White-fish eggs taken from the bottom of the Detroit River, a very extensive 

 spawning ground, while dredging in company with Mr. George Clark, at the close of the spawning 

 season, were found to be dead and white, or so coated and stained with the black ooze that they 

 could not have survived. In the pond on Grassy Island, where as many as ten thousand female 

 White-fish deposit their spawn in a season, we succeeded in taking between fifty and sixty embryo 

 fishes, by drawing a seine lined with milliuet, and a diligent search through several hours at the 

 surface in the month of April. 



" In obviating all of these evils, artificial propagation asserts its advantage, and though the 

 number of eggs that may be handled is exceedingly small compared with the millions sown by the 

 fishes, yet the number of fishes produced may really exceed the present production in a state of 

 nature. This assertion has ample proof in the restoration of fishes in regions where they have 

 been nearly exterminated, and even where no change was made in the restrictions upon the fishing 

 that might have assisted the increase. 



" The experience of the past few years has proved entirely the possibility of increasing the 

 numbers of the White-fish by artificial propagation. The running water in the troughs supplies 

 the conditions required by the eggs; the fertilization of the ova in the pan brings every egg in 

 contact with the milt; they lie undisturbed and free from injurious sediment or filthy water; the 

 spawn-eaters have no access to them whatever, and the dead eggs are immediately removed from 

 contact with the living ones ; the young fish are under control in the troughs until the ovisac is 

 absorbed, when they are ready to be placed in their natural home, the cold waters of the Northern 

 Lakes. 



"The experiments of Mr. Seth Green and Mr. N. W. Clark have reduced the loss of the eggs 

 to an inconsiderable number, and with a small outlay of money this fish may be restored with a 

 success equal to that of the shad in the rivers of the Atlantic coast. 



