LIFE HISTORY OF LAKE HERRING OF LAKE HURON 



347 



inore desirable species, the herring seems to maintain its numbers in Lake Huron. 

 (See Table 28.) 



Table 28. — Statistics of the catch and value of herring taken in Lake Huron in various years during 

 the period 1891 to 1926, published by the State of Michigan 



In the early fall (about October) the herring schools move inshore to spawn, and 

 in late spring, according to Doctor Koelz, they return to deeper water. Doctor Koelz 

 states that in some localities there appear to be two migratory movements — the 

 fish come in and go out both in the fall and spiing instead of remaining inshore all 

 winter. The factors that govern these movements are not definitely known. Tem- 

 perature changes in the water and food undoubtedly play important roles, if not the 

 most important ones. After June all adult herring have moved out of the shallow 

 water. They piobably swim near the surface in June and July and later repair to 

 greater depths. The maximum depth from which the species is known to have been 

 taken is 35 fathoms (Koelz). Only very few have ever been taken in water deeper 

 than 20 fathoms (Koelz). 



The lake herring takes its food occasionally from the bottom and more frequently 

 from the free water and subsists on small moUusks, crayfishes, insect larvae, fish eggs, 

 and especially on the minute plankton foniis, principally the Crustacea (Clemens 

 and Bigelow, 1922; Coker, 1922). It spawns chiefly in November in shallow water 

 (3 to 8 fathoms), preferably upon a sandy or gravelly bottom. Saginaw Bay, there- 

 fore, provides ideal breeding grounds for herring, and this accounts for the tremendous 

 numbers that gather there in the fall. Accoi-ding to the fishennen at Bay City, before 

 the waters of the Saginaw River were polluted large nmnbers of herring ascended it 

 to spawn. 



LIFE HISTORY OF ADULTS (AGE AND GROWTH) 



Little has been pubUshed thus far on the growth of the lake herring. A preUm- 

 inary paper by Clemens (1922) presents one table and two graphs, one illustrating the 

 rates of growth of four species of Leucichthys in Lake Erie — namely, artedi, prog- 

 naihus, eriensis, and sisco huronius — the other illustrating the relation of weight to 

 age of three Lake Erie species — artedi, prognathus, and eriensis. The number of fish 

 of each species examined was as follows : L. eriensis, 140 ; L. artedi, bb ; L. sisco huronius, 

 55; L. prognathus, 150. The maximum age and the maximum average length attained 

 by each of these species are as follows: L. eriensis, age 12, length 42 centimeters; 

 L. sisco huronius, age 9, length 41 centimeters; L. artedi, age 10, length 29 centimeters; 

 L. prognathus, age 8, length 27.5 centimeters. 



