PROGRESS IN BIOLOGICAL INQUIRIES, 1923. 



INTERIOR WATERS. 



COREGONIN^ OF THE GREAT LAKES. 



The iiwestigations on the Coregoninse, or whitefishes, of the Great 

 Lakes have been continued ; the field work was completed early in the 

 fiscal year, and the attention of the investigators has for some 

 months been directed toward the examination and comparison of 

 collections artd the compilation of data to be included in the final 

 report. Dr. Walter Koelz is engaged in work on the systematic 

 relations and natural history of the various species, while John Van 

 Oosten is working on age determinations from the scales, the rate of 

 growth, and allied problems. The problems involved in this investi- 

 gation are difficult and will require considerable time for solution, 

 but the progress made is regarded as most encouraging. 



The studies on the systematic relationships and natural history of 

 the Coregoninse were continued on Lake Superior and Lake Nipigon. 

 In Lake Superior an additional form was discovered and data on 

 the distribution of the coregonine fauna in the eastern section of the 

 lake were collected. In Lake Nipigon seven species were found, 

 all but one of them with representatives in the Great Lakes, and some 

 ecological data were secured. The preparation of the report on the 

 whitefishes and lake herrings of the Great Lakes is well advanced. 



Much additional material pertaining to the study of the life his- 

 tories has been collected and our knowledge of the species materially 

 advanced. Important information as to rate of growth, age at sexual 

 maturity, average length of life, maximum age attained, and average 

 length and weight at any year have been obtained. Where possible 

 the variations in rate of growth in different localities are noted with 

 a view to the planting of fry from hatcheries to the greatest ad- 

 vantage. 



By obtaining two large representative collections of the lake 

 herring taken from the same locality at the same season of different 

 years, it has been possible to answer with confidence certain critical 

 questions relative to the scale method of age determination as ap- 

 plied to the whitefish. 



During the year a report on experiments carried out on whitefish 

 of known age and life history was completed and is now in press. 

 This report presents evidence to show that the correspondence be- 

 tween the known age of the fish and the number of annuii, or yearly 

 rings, observed on the scales is exact and holds for old fish as well 

 as for the young. 



Much aid has been given to these investigations by the Univer- 

 sit}' of Michigan, particularly by Dr. Jacob Reighard, and also by 

 the State department of conservation. A fine spirit of cooperation 

 is manifested, which will materially aid and advance the work. 



MISSISSIPPI RIVEK FISHES. 



The investigation of the fishes of the Mississippi Basin has been 

 continued by members of the scientific staff' at the Fairport labora- 

 tory under supervision of the director, R. L. Barney. The work has 

 been confined largely to the hackleback sturgeon, rock sturgeon, 

 and sheepshead. A considerable amount of material on the growth, 

 food, sexual cycle, habits, etc., of both the rock and hackleback 

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