520 NATURAL HISTORY OF AQUATIC ANIMALS. 



frankly say that I should much prefer it to any spring water in this or any other State for hatching 

 White-fish. But there are some objections which arise in my mind even to this water. I am 

 aware that this species offish are natives of our great lakes awl rivers, and consequently it would 

 be supposed that this water must agree with them, and that success would be certain if this water 

 was used. But has it not occurred to all persons who have given this subject much thought that 

 much the largest proportion of these fish run to the shoals of those lakes during spawning season 

 to deposit their oval These shoals are the first to freeze over in the fall and the last to thaw in 

 the spring. This keeps at nearly the same temperature during incubation. Although it may be 

 said that during their migration from Lake Erie to Lake Saint Clair some deposit their spawn in 

 the rivers, it is not very probable that much of it is hatched. I am aware that many hatch in and 

 about the ponds where the fishermen preserve their fish for winter use. This tends to prove that 

 the shoals are the place where they hatch most largely, as the ice remains in these ponds much 

 longer in the spring than in the strong current in Detroit River. If water is used from this 

 river it must change in temperature many times during the winter, as it is well known that the 

 ice leaves the river quite often during the four and a half months of the period of incubation. No 

 one can gainsay the fact that in the hatching of fish ova, if the water is of a perfectly even tem- 

 perature, it will be attended with more favorable results than when frequently changing, from any 

 cause, even if such change is not more than two or three degrees. Is it not also a fact that the ice 

 frequently leaves the lower part of Lake Saint Glair early in March ? If so, would not the westerly 

 winds roll the water in the upper part of the river? This sediment would be deposited on the 

 eggs, and, in consequence of its fine, clammy nature, would be injurious to them. I noticed this 

 was the case in a little experimental arrangement of A. M. Campau, some two years since, where 

 this water was used. I examined these eggs several times during this process, and found a fine 

 clammy substance accumulating on them. They were gradually dying, and I do not think any 

 were hatched. These eggs were taken from our hatching boxes, and were in perfect condition, as 

 they were so far advanced in development that the embryo fish could be plainly seen with the 

 naked eye. For these reasons I am forced to the conclusion that there is more suitable water for 

 hatching this species of fish eggs than the Detroit River. 



"In conclusion, the advantages afforded American fish-culture from the cultivation of the 

 White-fish, as they have just been enumerated: These are, (1) more careful and perfect methods, 

 resulting from the experience in the culture of the most delicate and difficult species whose propa- 

 gation has been attempted by culturists; (2) the perfection of three forms of apparatus for 

 hatching fish eggs, embodying the important improvements of facility in handling the eggs and 

 removing sediment and coufervae, and greatly economizing space; (3) the contrivance of a 

 superior case for the carriage of eggs; and, besides, a possibly successful, entirely new method in 

 the hatching of eggs and the discussion of and practical tests of conditions of water suitable to 

 the eggs of a species that we are not (at any rate thus far) able to supply with food." 



"These experiments," wrote Mr. Milner, referring to those made by Mr. N. W. Clark, 

 "were all attended with considerable success, though the large percentage of loss, compared 

 with that in trout and salmon hatching, was anything but encouraging. The screens in the 

 troughs, in most instances, were the same as those used for the Trout, and the embryo White- 

 fishes, being smaller, escaped and ran over into the waste troughs and down into the ponds 

 below. This was in some measure a fortunate circumstance, at Mr. Wilmot's establishment, for 

 the young fish, finding their natural food in the ponds, grew and thrived, and afforded the only 

 positive data there are of their rate of growth. In the succeeding year (1870) Mr. Green and Mr. 



