16 AMERICAN FISH CULTURE. 



care for their young, and lead them about as a hen does her 

 chickens. 



The time occupied in hatching the spawn also varies. 

 That of the salmon requires from forty to over two hun- 

 dred days, according to the temperature of the water ; while 

 the spawn of the shad in water at 75 hatches in fifty-two 

 to sixty hours. 



The number of eggs produced by different species vary 

 as wide as the time of incubation. A salmon of ten pounds 

 only gives ten thousand eggs, or a thousand to each pound 

 of its weight; while a good-sized codfish gives a million, a 

 herring forty or fifty thousand, and a five-pound shad a 

 hundred thousand. But a small percentage of ova produce 

 fish, as it is food for fishes and other aquatic animals. If 

 all the fish eggs produced were hatched and the fry arrived 

 at mature age, the seas would be so full that they could 

 not be navigated, and rivers and lakes would be plethoric. 

 The object of fish culture is to profit by knowledge of the 

 facts I have mentioned, and to turn a portion of the waste 

 of piscine life to human account. 



As far back as our knowledge of the Chinese extends, 

 we find that fecundated fish spawn with them has been an 

 article of traffic. The manner of procuring it is by placing 

 fagots on frames permanently fixed in waters where fish 

 are accustomed to spawn. At the proper time the fagots 

 are collected with the spawn adhering, and the ova either 

 hatched out by those who collect it, or is sold and trans- 

 ported in water. The flooded rice-fields are frequently 

 used for raising the young fish. I would here remark that 



