180 tr. S. BUEEAU OF FISHERIES 



Considerable -work, however, has been done with other species of 

 ])ondfishes inchiding the smaUmoiith black bass, Micro'pterus 

 iloJomku^ the black and white crappies Pamoxm sparoides and P. 

 annvJaris, and the bliiegill sunfish Lepo?nls incisor. 



DESCRIPTION OF PONDS 



The location and area of the ponds at the Fairport station are 

 shown in Fitrure 1. Several of the ponds are so small as to be of 

 little value for experimental purposes and practically all of the 

 experiments described in this paper were conducted in the D, E, 

 and F series of ponds. The D series comprises 10 dirt ponds ranging 

 in size from 0.094 of an acre to 3.54 acres, only 3 of which are less 

 than one-half acre in area. The E series comprises 4 small dirt 

 l^onds of nearly equal size. Two of these ponds are slightly larger 



Ficriuc li. — rartial view of the D series of pomls at tbe Fairpoi't station 



tlian the others, having an area of 0.128 acre, while the two smaller 

 are only 0.121 acre in area. The F series includes three small dirt 

 ponds, each having an area of 0.073 acre. 



The bottoms of all the ponds slope very gradually from the upper 

 end to the kettle so that the water at one end of the pond may reach 

 a depth of 3.5 to 7 feet — depending on the size of the pond — while 

 at the other end it is only a few inches deep. The ponds are so con- 

 structed that they can be completely drained whenever desired, 

 which makes possible a complete recovery of all fish. The water 

 supply is derived from the Mississippi River and is first pumped 

 into the reservoir shown in Figure 1. From the reservoir it is 

 fed to the ponds by gravity through a system of underground pipes. 

 Only enough water is allowed to flow into the j)onds to replace that 

 lost by evaporation and seepage. 



Practically all of the ponds support a luxuriant growth of aquatic 

 vegetation throughout the summer. The plants are mostly of the 



