GREAT LAKES COREGONIDS 



399 



fishing tugs show that the movement began about September 13 in 1915. From 

 this date until October 8 from 2,100 to 4,400 pounds of fish were taken daily from 5 

 miles of nets lifted after having been set two and three nights. Previous to this 

 run 1,000 to 1,500 pounds in nets five nights out were considered good lifts. After 

 October 8 the weight of the lifts dropped rapidly. On the 8th, 2,450 pounds were 

 taken; on the 9th, 1,555 pounds; on the 19th, 595 pounds; on the 20th, 520 pounds. 

 What becomes of the fish after they leave the spawning grounds is unknown. Cer- 

 tainly they do not return in any numbers before June, because few chubs of any kind 

 are caught here from the opening of navigation until June. 



These are the only spawning grounds known. The occurrence of small individuals 

 in the 13^-inch nets at Harbor Beach, Mich., in March, 1919, indicates that the species 

 also spawns somewhere in the southern part of the lake. An occasional female among 

 these individuals shows large but not ripe eggs, and an occasional male has well- 

 developed testes and a trace of nuptial pearls. Most of the specimens, however, 

 exhibit sex organs apparently normal for the species. It is possible that specimens 

 spawning for the first time mature irregularly, an assumption that is strengthened 

 by the finding of small specimens of this species in Lake Superior with ripe eggs in 

 June (see p. 384). 



FOOD 



Only seven stomachs were examined from specimens collected in September, 1917, 

 off Cheboygan, Mich. Mysis and Pontoporeia comprised 95 per cent of the food. 

 Pisidium, pebbles, wood fragments, larval chironomids, and unidentifiable bottom 

 material constituted the rest. 



LEUCICHTHYS REIGHARDI Koelz 



Reighard's Chub (Figs. 17 and 18) 



Leucichthys reighardi Koelz, 1924, pp. 5-8, Lake Michigan; Dymond, 1926, pp. 65-66, PI. VII, 

 Lake Nipigon. 



Leucichthys reighardi has been described from southern Lake Michigan. Races 

 of the species also occur, so far as is known, in the northern part of that lake and in 

 Lakes Ontario, Superior, and Nipigon. In all four lakes it is represented by relatively 

 small decidedly terete fishes with included mandible, relatively few gill rakers on the 

 branchial arches, few scales in the lateral line, short paired fins (except in Nipigon), 

 and short snout. Each race, however, has its own peculiarities, but it seems desirable 

 to name only the two extremes of development. The race in Lake Ontario is nearly 

 like the typical one, differing chiefly in the relatively somewhat smaller size of head 

 and eye. In both lakes the forms appear to prefer the shallower waters and to spawn 

 in May or June. The race of northern Lake Michigan tends to have a longer snout 

 and maxillary. The Superior and Nipigon forms show more differences, arid the 

 Nipigon form, which shows the extreme development, has been named dymondi. 

 These two forms differ from the typical one chiefly in the relatively longer head, 

 maxillary, and pectoral fins, fewer scales in the lateral fine, greater number of dorsal 

 and anal rays, in the reduction of the pigmentation of the head, and in the less vertical 

 position of the premaxillaries. The Nipigon race also differs slightly in a few other 

 proportions. Both races likewise prefer shallow water but spawn probably in 

 November. 



94995—29 8 



