724 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



that the hist are usually in the same couditiou. The first are perhaps 

 from eggs that for some reason have remained in the parent after they 

 should have been thrown; the great majority of healthy fish coming later 

 probably represent eggs in their normal couditiou ; and the ^eak ones 

 hatching last may be from eggs, that, though not thoroughly matured 

 when taken, had just reached that stage where impregnation became 

 possible. The time elapsing after the eggs leave the fish before they 

 come in contact with the milt may also affect the time of hatching. 



Experiments in these lines would be of practical importance in deter- 

 mining how many good eggs could be taken from the fish at one time ; 

 how often eggs might be taken from the same individual, and, also, the 

 most desirable time for applying the milt. 



A table of temperature observations, showing the condition of both 

 air and water at the first high and low water after 7 a. m., will be found 

 further on. The temperature of the water in the hatchery was always 

 from one to two degrees higher, being raised a little in passing through 

 the pipes. From this table we find that the average time requiied for 

 hatching eggs, iu water of different temperatures^ was as follows : 



Days. 



In water having an average temijerature of 45° F. 13 



In water having an average temperature of 41© F , 16 



In water having an average temperature of 38° F 20 



In water having an average temperature of 36° F 24 



In water having an average temperature of 34° F 31 



In water having an average temperature of 33° F 34 



In water having an average temperature of 31° F 50 



The water of the harbor reached, and remained for a number of days, 

 at a temperature of 30°, but the eggs in the floating box remained unin- 

 jured, even though the little fish in them were well advanced, while the 

 large cod iu the live-boxes within a few feet of them were all frozen to 

 death. 



Several attempts were made to hasten the development of the egg, 

 by raising the temperature of the water by means of steam-pipes. The 

 time of hatching was frequently shortened in this way, but in all cases 

 the fish seemed premature and soon died. The failure in these experi- 

 ments may be due to the crude apparatus that could not be regulated so 

 as to keep the temi)erature constant and avoid fluctuations. These dif- 

 ficulties overcome, it seems not at all improbable that the process of 

 hatching could be materially shortened, and the fish gradually accus- 

 tomed to cooler water until the natural temperature of the harbor should 

 be reached, when they could be put out. 



The problem of hastening or retarding development in the egg is a 

 very important one. Fish-culturists have given some attention to the 

 subject, but none have yet succeeded in the invention of apparatus by 

 which the water can be kept constantly at any given temperature. 



Eipe fish were found nearly every time the live-boxes were overhauled, 



