WHITEFISH- FISHERY OF LAKES HURON AND MICHIGAN 



351 



Table 2.5. — Number of legal and illegal whitefish per lift of pound nets and deep trap nets in the Saginaw 



Bay area (ports of Au Sable-Oscoda, East Tawas, and Bay Port), 1931-1932 



[Number of lifts in parentheses. Asterisks indicate concentrations] 



Distribution of legal-sized whitefish. — Again there is evidence of an onshore move- 

 ment of legal whitefish during the summer followed by a return to deeper water in early 

 autumn, apparently beginning in August. (See also p. 350.) The depths of maximum 

 concentration in the different months were: May — more than 120 feet; June and July — 

 101-110 feet (the shift was more toward shallower water in July than in June); 

 August — 91-100 feet; September — 111-120 feet; October — more than 120 feet (only two 

 intervals represented). There were two peaks in the August data (41-60 feet and 91- 

 100 feet) and in the September data (71-80 feet and 111-120 feet). However, the 

 number of lifts was so small at some depths that it cannot be concluded that the 

 whitefish were concentrated at two depth intervals. The average number of legal 

 whitefish per lift through the entire season increased continuously from shallow water 

 (less than 41 feet) to the maximum at 81-90 feet, declined in the next three intervals, 

 and increased slightly at depths greater than 120 feet. 



Distribution of illegal-sized whitefish. — The data on the bathymetric distribution 

 of young whitefish indicate an onshore movement followed by an offshore movement 

 similar to that of legal fish. The depths of maximum concentration were: May, June, 

 and July — 101-110 feet (in each succeeding month, however, the shift was toward the 

 shallower water); August — 81-90 feet; September — 101-110 feet; October — more than 

 120 feet. In the averages for the entire season the maxima for legal and illegal fish 



