12 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



2800 — 



—,400 



— 300 



O 

 < 



I- 



— 200 z 



o 

 en 



1930 



1935 



1940 



945 



Figure 11. — Lake herring: Production (solid line), abundance (long dashes), and intensity of the fishery (short dashes) 

 in State of Michigan waters of Green Bay, 1929-49, as percentages of the 1929-43 mean. Production is also given in 

 pounds on scale at the left. 



herring in 1934 and by the suckers in 1933, 1935, 

 and 1944. These shifts of dominance were ac- 

 companied by relatively wide ranges in the per- 

 centage contribution of whitefish, lake herring, and 

 smelt and can be related to the fluctuations of pro- 

 duction described earlier. (It is to be noted that 

 suckers, which exhibited no periodicity in pro- 

 duction but rather showed erratic variations, failed 

 to dominate the catch in consecutive years.) 



Comparisons of production data for 1891-1908 

 and 1929-49 (tables 2, 4, and 6) reveal a much 

 lower level of total yield in the latter period. The 

 average annual output of 3,582,000 pounds for 

 all species combined in 1929-49 was 3,503,000 

 pounds less than the 1891-1908 mean of 7,085,000 

 pounds — a decrease of 49.4 percent. Examina- 

 tion of the statistics for individual species shows 

 that the decline in the production of lake herring 

 alone more than accounted for this decrease. The 

 catch of this species fell from 5,841,000 pounds in 



] 891-1908 to 1,070,000 pounds in 1929-49— a drop 

 of 4,771,000 pounds, or 81.7 percent. For species 

 other than lake herring the combined yield in- 

 creased from 1,244,000 pounds in 1891-1908 to 

 2,512,000 pounds in 1929-49 — an increase of 

 1,268,000 pounds, or 102.9 percent. Even if we 

 exclude the smelt, an exotic variety not present 

 in 1891-1908, the 1929-19 catch of fish other than 

 lake herring was 52.5 percent gi - eater than that of 

 the earlier period. The greatest increase of pro- 

 duction, aside from the introduced smelt, was that 

 of whitefish (from 159,000 pounds in 1891-1908 

 to 714,000 pounds in 1929-49— a rise of 555,000 

 pounds, or 349.1 percent) . The increase was large 

 also for suckers (398,000 pounds in 1891-1908 and 

 699,000 pounds in 1929-49— a rise of 301,000 

 pounds, or 75.6 percent). These increases more 

 than compensated the declines in the output of the 

 remaining species (herring excluded) which were 

 all less than 100,000 pounds (largest drop, lake 



