24 



clear or slightly opaque, will transmit enough light 

 to keep the plants actively supplying oxygen. During 

 winters of early and heavy snows, it will be necessary 

 to keep the ice clear of snow. Hasler, Thomsen, and 

 Neiss (1946) recommend the following method: "Winter 

 kill may be avoided by removing the snow beginning with 

 the first snowfall and continuing throughout the winter. 

 To do this, simply chop a hole in the ice, lower an 

 intake hose of a centrifugal pump powered by' a small 

 gasoline engine. Spray the water about until the snow 

 melts on three-quarters of the pond area. The newly 

 formed ice will transmit enough light so that the 

 microscopic plants can replenish the oxygen supply. " 



Selection of species 



There are many factors to consider in choosing a 

 bait species to raise. Several species should be reared 

 if the dealer expects a sustained income from his 

 operations. Several species, if properly selected, 

 will provide suitable sizes through most of the year. 

 As a general rule, a beginner should raise only one 

 species in each pond. 



The following characteristics should be considered 

 in selecting a bait species for propagation: 



a. The fish should be reasonably tolerant to 

 seining, handling, and transporting. 



b. Fish must have a rapid rate of growth. Even 

 then, some species must beheld more than one winter in 

 northern latitudes. 



c. The adults must be large enough to be suitable 

 bait for the predominant game fish of the region. 



d. The species should have an extended spawning 

 season. 



e. The fish should be prolific in reproduction. 



f. The fish should not be excessively cannibalis- 

 tic. 



g. The fish should be resistant to the harsher 

 fish diseases. 



h. Those species lacking spines and hard parts 

 are most suitable. 



i. The minnow should be one that thrives under 

 cultivation. 



j. The fish should be suited to the ponds avail- 

 able. 



k. Keeping qualities are of the utmost importance. 



1. Species that are hardy on the hook sell best. 



None of the bait species will fill all these con- 



