FISH-CULTURAL PRACTICES IN THE BUREAU OF FISHERIES. 709 



wise be possible. The method of spawntaking at Put-in Bay is in general as 

 follows: 



On account of the adhesiveness of the eggs a wooden or fiber receptacle is 

 used instead of the usual tin spawning pan. A liberal quantity of milt is applied, 

 the mass is thoroughly stirred with a feather or with the bare fingers, and a 

 little water is added. Then pan and contents are lowered into a keg, containing 

 about 2 gallons of water, and the pan is carefully emptied. This process is 

 repeated until the keg is about one-third full. The eggs are now left undis- 

 turbed until spawning operations are ended — not over two or three hours; then 

 water is added, a little at a time, until the keg is nearly full. Some of the 

 water is then poured off and more added, this process being continued until all 

 the milt is washed off and the eggs are thoroughly water hardened. 



The chief precaution during the water-hardening is this constant pouring 

 off and addition of water. Care must l^e taken in pouring the water to have 

 it fall not directly on the eggs but against the side of the keg. During this 

 period the eggs must not be stirred, for the reason, it is said, that such motion 

 tends to rupture them. It is also important to avoid exposure of the eggs to 

 the air, since because of their adhesiveness they will form in a nearly solid mass. 

 When they are sufficiently water-hardened they may be separated by gently 

 loosening them with the bare hand. After separating them it is necessary to 

 change the water frequently until they can be transferred to hatching jars. 



The fact that pike perch spawn in the spring, while fall is the spawning 

 season of the whitefish, makes it possible to utilize the same batteries and 

 other hatching equipment for both species. 



In order to overcome the adhesiveness of pike perch eggs and prevent 

 their forming unwieldy masses, it was formerly considered necessary to use 

 muck or starch in the water into which the eggs are placed immediately after 

 fertilization. The use of muck has now been entirely abandoned and neither 

 starch nor muck is used at Put-in Bay. 



At Swanton, Vt., the pike perch is regarded as of more value as a game 

 fish than for the maintenance of a commercial fishery. The hatchery is stocked 

 with eggs taken from fish captured purely for fish-culture purposes from the 

 waters of Missisquoi Bay and River. The conditions under which the eggs are 

 taken are more favorable than those existing on the Great Lakes, it being possi- 

 ble to pen the unripe fish for a week or more while maturing, the penning crates 

 being located in a current of water in the river. Delivery of the eggs at the 

 hatchery is also more expeditious. 



In the manipulation of eggs here the methods are somewhat different from 

 those just described. After impregnation in the usual manner a little water 

 is added and the eggs are left for five to eight minutes ; then more water is added 

 and the eggs are withdrawn carefully into half a bucket of water into which two 



