PROGRESS IN BIOLOGICAL INQUIRIES, 193 3 351 



blue i)ike-|)oii-h. ami proliably also of (he saut:;('i'. CoinpariiiLC the 

 orowtli rate of tho throe species of ])ike-perehes it was found that 

 the yellow ]Mke-i)er('h ranks first in the rapidity of (growth, saup^er 

 ranks second, and the blue pike third. The sanp;er, however, be- 

 comes sexually mature at a smaller size than does the blue pike- 

 perch and the latter matures at a smaller size than does the yellow 

 pike -perch. 



A study of the relationship of percentage of immaturity to the 

 existin<j lejxal size limits now in force in Lake Erie indicates that the 

 present size limits of all three species of pike-perches should be 

 increased to afford better protection to s])awninf!^ females. In order 

 to help insure spaAvning by females at least once, a size limit of 15 

 inches total length is indicated as a minimum for yellow pike-perch. 

 On a similar basis, a minimum of I31/2 inches total length is recom- 

 mended for blue pike-perch and a minimum of I21/2 inches total 

 length for saugers. 



A rei:)ort was also completed on the analyses of the stomach con- 

 tents of the yellow pike-perch, sauger, and grass pike from Lake 

 Champlain. 



YELLOW PERCH 



Studies of the life history of the yellow perch of the Great Lakes 

 were continued. Scales from 2,434 fish were examined during 1933. 

 Of these 2,434 scale samples, 1,095 were collected from western Lake 

 Erie in 1929, 1930, and 1932; 513 were collected from Green Bay in 

 1932; 606 were collected from Saginaw Bay in 1929 and 1930; "and 

 220 were collected by the LTniversity of Michigan Museum of 

 Zoology during different years. Growth rates have been calculated 

 for all except the Saginaw Bay collections. 



Although detailed comparisons have not been made as yet, the 

 growth rate of the fish from Green Bay appears to be very similar 

 to that found in Lake Erie. This conclusion refutes the argument 

 of the Green Bay fishermen of Wisconsin that the perch in their 

 waters are dwarfed in growth and that therefore a small size limit 

 on this species in Wisconsin waters is justified and necessary. The 

 Lake Erie collections of 1929, 1930, and 1932 when compared with 

 the 1927-28 collections seem to show that the yellow perch has 

 increased its growth rate somewdiat after 1928. The yellow perch 

 from Saginaw Bay appear to grow at a faster rate than those from 

 Lake Erie or Green Bay. 



To check the suspicion that more than one race of yellow perch 

 inhabited Lake Erie, body depth measurements were compiled for 

 613 yellow ])erch collected off Lorain, Ohio, and for 114 yellow ])erch 

 collected off Erie, Pa., both collections having been made in 1929. 

 Slight differences in bod}^ depth were found between the sexes of a 

 collection. The fish collected off Erie, Pa., were found to be some- 

 Avhat slimmer bodied than those taken off Lorain. Ohio, but the 

 difference was found to be so small that on the basis of these data it 

 cannot be concluded that more than one race of perch exists in Lake 

 Erie. Additional evidence will be sought in the comparative study 

 of the growth rates of the yellow perch taken both from the western 

 and eastern end of Lake Erie. 



