MILNER ON THE ARTIFICIAL CULTURE OF THE SHAD. 447 



and the water is, without doubt, nearly as good as if taken directly 

 from its source. 



On the few occasions when we have been obliged to obtain the water 

 from the tank in the tender, it was found clear and i^ure, and with uo 

 indications of oil or grease, and it is probable it would always "be 

 found so. 



{22d.) Temperature of the water in the cans. — The temperature of the 

 water which the fish are in is also an essential point in their welfare. 



A too low temperature produces lethargy and torpidity in the young 

 shad, which, if suftered too long, occasions death. 



The young shad suffer in low temperatures in which the SalmonicJw 

 thrive well. By experiment it has been proven that between 65° and 

 72° the shad are found to be in the best condition. The springs of the 

 lake region have from 40° to 50^ of temperature, the deeper wells from 

 54° to 60°, and the streams from near the freezing-point, in winter, to 

 85°, perhaps more, in hot summer-weather. 



Where there is six or more degrees difference in the water of the 

 reserve-can and of that on the fishes, the temperature of the fresh 

 water should be moderated before using it. This is readily done by 

 preserving a portion of the stale water drawn from the fish, which can 

 be aerated by repeated pouring from the dipper, the pail is then filled up 

 from the fresh water, and according to the proportions used the tem- 

 perature can be raised before supplying the can containing fish. 



A temperature higher than 80° is dangerous, as the fish become weak, 

 the supply of respiratory gases in the water is much less, and the 

 fish very soon die. In hot weather the use of ice is necessary where 

 water from wells or springs cannot be obtained. The ice should 

 be applied in the reserve-can, and not in the cans with the fishes, as in 

 knocking about on the surface it kills many of them, and if in the 

 splashings of the water any are lodged on top of the ice they soon die. 

 Caution must be taken in using ice in the fresh water, not to put in sufii- 

 cieut to reduce the temperature below the proper standard. 



(22e.) Transferring the shad from the cans to the river. — On arriving 

 at the river the first necessity is to determine that the tempera- 

 tures of the cans and the stream are so nearly equal as not to 

 endanger the fish when consigned to their new home. If there is five 

 or more degrees difference, it can be readily equalized by drawing a 

 quantity of water from the cans and filling them up again with the 

 river-water. 



The locality for planting should be chosen so that the fish will not be 

 too soon carried into the whirl of a rapid current, but may recruit for a 

 time from their fatigue, and, possibly, their hunger, before being obliged 

 to struggle with swift running water. 



Another very important matter is to avoid schools of minnows or 

 other small fishes, who will congregate at the spot in large numbers 

 and devour a large proportion of the fish that have cost a large amount 



