GREAT LAKES COREGONIDS 



507 



GEOGRAPHICAL DISTRIBUTION 



As in the other lakes, the herring of Lake Nipigon move in schools, and these 

 schools are seen often off the dock at Macdiarmid. No commercial fishing operations 

 whatever are conducted on Lake Nipigon for herring, or for any other species of 

 Leucichthys, for that matter, and all that is known about the occurrence and distri- 

 bution of the species in the lake has been learned from the employment of small- 

 meshed nets by the University of Toronto investigators and me. The data from 

 these nets indicate that herring occur throughout the lake at suitable depths. The 

 locations in the lake from which specimens have been obtained are given in Table 75, 

 and they are platted in Figure 2. 



SEASONAL MOVEMENTS 



Nothing is known about seasonal movements, as the University of Toronto 

 investigators always have been engaged only in summer and have made no particular 

 efforts to study the habits of herring. Sets of nets were made during the summer, 

 however, at all depths to 65 fathoms, and it is interesting to note in Table 75 that 

 between July 16 and September 11 in several seasons no numbers of individuals were 

 taken in the netting at depths of more than 15 fathoms. The deepest set that showed 

 herring was made by me off Macdiarmid in 30 fathoms on July 28, 1922, and only one 

 individual was present among dozens of other Leucichthys (record 1). It is 

 probable, then, that the species at no time frequents great depths and during the 

 summer either traverses the surface waters of the open lake, as in Lake Superior, or 

 sinks to depths of 15 fathoms or less. The schools, in that case, without doubt come 

 ashore in fall to spawn. 



BREEDING HABITS 



Nothing is known of the time of spawning, but none of the individuals collected 

 as late as September showed well-developed sex organs, and the two specimens taken 

 on October 26, 1922 (record 21), were not yet ripe. The spawning season is probably 

 in late November, as in Lake Superior, and the spawning grounds are probably in 

 shallow water, as is usual for the species. 



Leucichthys artedi artedi and artedi albus of Lake Ontario 



The artedi of Ontario are variable, as in Lake Erie, and the same two types are 

 represented, namely the terete blueback and the deep, more compressed form. The 

 latter, however, is usually always elliptical in side view in Lake Ontario. The differ- 

 ence between the two types in Lake Ontario is largely in this aforementioned body 

 shape and color, and as these characters, excepting the length-depth ratio (L/D), do 

 not lend themselves to numerical expression, the characters that can be expressed 

 thus may be combined for both types for comparison with the combined types for 

 Lake Erie. The races may be compared better and in more detail in Tables 67 and 

 78, where 20 large albus and 10 large artedi for Lake Erie and 10 large specimens near- 

 est the artedi type and 10 nearest the albus type for Lake Ontario are analyzed. The 



