4 U. S. BUREAU OF FISHERIES. 



THE WHITEFISH AND ITS RELATIVES IN THE GREAT LAKES, 



During 1921 the investigation of the systematic relationships 

 and habits of the whitefish and rehited species of the Great Lakes 

 was extended to Lakes Ontario and Superior, On neither lake are 

 fishing operations for deep-water ciscoes now carried on, either be- 

 cause of the exhaustion of the supply of the species originally fished 

 for or because the existence of these species is unknown. In Lake 

 Ontario, in addition to the two whitefishes (Coregonus and Pro- 

 sopium), which occur also in Lake Huron and Lake Michigan, there 

 were found five species of Leucichth3\s (ciscoes), all but one of 

 them {artedi)^ the so-called "Lake Herring." being deep-water 

 forms. Three of them have never been taken in the commercial 

 nets allowed in American waters. These species were caught in 

 abundance in the special nets set out of several ports and doubtless 

 would support a fishery. In Lake Superior there were found one 

 Coregonus, one Prosopium, and five species of Leucichthys. Of the 

 latter only two {artedi and senifhicus) are known to be abundant. 

 None of the species taken in either lake is new, and, Avith the ex- 

 ception of one from each, the coregonine fauna of the two lakes is 

 derived from the same stock. Singularly enough, the one species 

 of Ontario that does not occur in Superior has so far been discov- 

 ered elsewhere only in Lake Michigan, where it has latterly been 

 found to be very common during its spawning season. It is hoped 

 to complete for publication during the coming year a comprehensive 

 report upon the investigations, which have now been conducted for 

 several years and the results of which should form a valuable part 

 of the foundation of knoAvledge upon which must rest any intelligent 

 attempts to conserve the fishery resources of the Great Lakes. 



As is now well known, it is possible to approach the study of the 

 biology of fishes through careful examination of the scales, and 

 provided that sufficiently large numbers of fish are used and that 

 due care is taken to meet the requirements of sound analysis of data, 

 much information regarding fish may be gained in this way that it 

 is not possible to secure by any other means. The investigation of 

 the coregonine fishes of the Great Lakes just mentioned has been sup- 

 plemented therefore by studies of the scales conducted by John van 

 Oosten, scientific assistant, under the direction of Prof. Jacob Reig- 

 hard in the University of Michigan. Conditions made it necessary 

 to restrict attention to the various species obtained from Lake Huron. 

 Up to the present time enough has been learned about the Avhitefish, 

 pilot, blackfin, and lake herring to warrant certain general statements 

 concerning their life histories. It has been found that the whitefish, 

 Coregonus cJupeaformis, is the fastest growing fish of the 10 species 

 from Lake Huron. It attains an average length of 449 millimeters 

 in the seventh year. For the other three species the average lengths 

 in that year are as follows: The pilot, C. quadrilateraJis, 295 milli- 

 meters; the blackfin, C. nigripinnis^ 267 millimeters; and the "her- 

 ring" (so called), C. artedi, 258 millimeters. On comparing the 

 growth curves of these four species of coregonines for the first seven 

 years of life it appears that the whitefish is a comparatively fast- 

 growing fish during each of the seven years. The " herring " grows 

 nearly as rapidly as the whitefish during the first two years, about 

 ■one-half as rapidly during the third year, and much more slowly 



