GRADING FISH 



nows is counted when a large num- 

 ber of minnows are to be sold by 

 the dozen. 



GRADING FISH 



The most practical method of 

 sorting, or grading, fish — with the 

 least amount of damage to the fish 

 involved — is by using a mechanical 

 grader. Similar to those used in 

 trout culture, the bait-fish grader 

 consists of a wooden box having a 

 bottom of tubular grating (fig. 23). 

 The tubes, of lightweight metal of 

 about a i4"i'^ch diameter, extend 



across the bottom of the grader, 

 producing a sievelike structure. 

 By regulating the spacing between 

 the tubes, fish of a desired size can 

 be retained in the box or permitted 

 to pass through. If the fish are to 

 be graded in several sizes, several 

 grading boxes will be necessary, one 

 for each size group desired. 



Periodic sorting of the fish 

 throughout the growing season will 

 reduce the number of small fish that 

 have to be held through the winter, 

 and will result in greater produc- 

 tion of fish of a desirable bait size. 



Figure 23. — Two sizes of slat sorting boxes used in grading minnows, 

 courtesy of the Minnesota Department of Conservation.) 



( Photograph 



39 



