134 Fortieth Annual Meeting 



previous to the cold snap are lost ; then the fish desert their 

 nests and all is confusion. 



Previous to three years ago at the Mill Creek Station we 

 were never sure that all eggs deposited would produce fry, 

 owing to the conditions which I have just described. This 

 uncertainty in regard to results would sometimes be very 

 trying ; then it occurred to me that possibly some way could 

 be devised whereby the fish might be prevented from spawn- 

 ing until all danger of cold snaps had passed. 



The plan finally adopted is to place all the breeding bass 

 in the wintering ponds, which are deeper than the others; 

 this is done in the late fall and plenty of minnows are intro- 

 duced to feed them until the spawning season the following 

 spring. In spring a large supply of water is turned on and 

 is kept as cool as possible by adding what spring water is 

 available at the station. In these ponds the fish have no 

 nests or other places to spawn, and they are too crowded to 

 spawn, even under more favorable conditions. They are 

 held there until all danger of the spawn being destroyed by 

 cold weather is past. In the meantime the spawning ponds 

 have been prepared, nests placed, and everything put in 

 readiness for the breeders. When spawning cannot be 

 postponed any longer the fish are sorted and placed in the 

 spawning ponds. The fish cover their nests with eggs 

 within 24 hours after being transferred. During the past 

 three seasons this plan has worked so successfully that no 

 poor nests have resulted, and every nest has been produc- 

 tive. I think possibly this plan could be carried further 

 by separating the males from the females ; then there would 

 be no chances for them to spawn. 



I know from an experiment carried on at the Mill Creek 

 Station that a bass may hold her eggs until some time in 

 July. One season, having about fifteen surplus females, 

 I placed them in a pond by themselves. They were seined, 

 and one of them was opened about every ten days from the 

 middle of May until the middle of July. The ova were 

 found to be in good condition until the last seining, which 



