268 



BULLETIN OF THE BUREAU OF FISHERIES 



the technique of the method and of the errors involved in its use); and (3) to apply 

 the method, if found valid, in a study of the life history of the species. 



Koelz (1929) recognizes 11 species of coregonids in the Great Lakes Basin (10 

 in the Great Lakes). Preliminary examination of the scales of these species shows 

 them to be so much alike that a method found valid for one species may be applied 

 with confidence to the others. The form selected for this study is the lake herring 

 (Leucichthys artedi Le Sueur) of Lake Huron, known also as blueback. (Fig. 15.) Its 

 abundance and cheapness and the accessibility of the extensive Lake Huron fisheries 

 determined the choice. Data on other coregonids of the Great Lakes have been 

 accumulated and will be used in later studies. 



MATERIAL 



All the lake-herring specunens collected by Doctor Koelz in 1917 and 1919 have 

 been at my disposal, and the scales of all have been studied. In order to have larger 

 series than were needed by Doctor Koelz for systematic purposes, I collected additional 

 material in 1921, 1922, 1923, and 1924 at Bay City, Mich, (see fig. 1), and in 1922 at 

 Oscoda near the mouth of the Au Sable River. Bay City ranks first in the herring 

 industry of Lake Huron, and I believed that with its protected Saginaw Bay it would 

 be more likely to furnish homogeneous material than the more open ports on the 

 lake proper. The Bay City material collected in 1921, 1922, and 1923 was taken by 

 pound nets set at Tobico, about 3 miles west of the mouth of the Saginaw River. 

 The 1924 material was taken from pound nets set on various sand bars (Tobico, 

 Nayanquing, Au Gres, and Gravelly Point) in Saginaw Bay. 



The ports at which collections were made, with the dates and numbers of speci- 

 mens, arc given in Table 1. Of the 3,724 lake herring examined, 321 were taken bj- 

 Doctor Koelz at various ports and 3,403 by me in the region of Bay City and Oscoda. 



Table 1. — Ports on Lake Huron at which herring were collected and their scales examined 



Locality 



Date 



Harbor Beach Dec. 



Bay City Oct. 



Do  Oct. 



Oct. 

 Nov 

 Nov, 

 Nov 

 Nov 

 Nov 

 Nov 

 Nov 

 Nov, 

 Nov. 

 Nov. 

 Nov. 

 Nov. 

 Nov. 

 Deo. 

 Oct. 

 Nov 

 Aug. 

 Sept 

 Sept 

 Sept 



Bay City (Tobico) 



Bay City 



Do 



Bay City (Tobico) 



Do.... 



Do 



Do 



Do 



Bay City (Nayanquing) . . . 



Do 



Do 



Do 



Bay City (Au Gres) 



Bay City (Gravelly Point) . 



Do 



East Tawas 



Oscoda 



Alpena 



Do 



Do 



Do 



9, 1917 



25, 1917 



26,27. 1921. 



29. 1921 



. 3, 1921 



.4, 1921 



. 1, 1922 



. 12, 1923.... 

 . 23, 1924.... 

 . 25, 192-1.... 



27, 28, 1924 

 .22, 1924.... 



24, 1924.-.. 

 , 27. 1924.... 

 , 28, 1924.... 

 ,21, 1924.... 

 ,30, 1924 



4, 1924 



22, 1917 



2, 1922 



13, 1917.... 



.5,1917 



.8, 1917 



. 10, lfcl7.... 



Number 

 taken 



11 



17 

 292 

 267 

 81 

 32 

 501 

 519 

 109 

 197 



146 



111 



3 



119 



367 



175 



25 



362 



11 



1 



9 



13 



Locality 



Alpena... 



Do 



Do 



Do 



Do 



Do 



Do 



Rogers City 



Cheboygan 



St. Ignace.. 



Duck Islands 



Lake Mindemoya. 



Gorc Bay... 



Kagawong 



Do 



Tobermory 



Wiarton - 



Do 



Do 



Killarney 



Blind River 



Total. 



Date 



Sept. 12, 

 Sept. 14, 

 Sept. 17, 

 Sept. 22, 

 ■Sept. 24, 

 Sept. 20. 

 Nov, 15 

 Oct. 14, 

 Sept. 29 

 July 17, 

 Oct. 22, 

 Nov. 12 

 Nov. 10 

 .do 



1917.. 



1917.. 



1917.. 



1917.. 



1917.. 

 , 1917.. 



1919.. 

 1917... 

 , 1917.. 

 1917.. 

 1919.. 



1917.. 



1917.. 



Oct. 16, 1919.. 

 Oct. 2, 1919... 

 Nov. 6, 1917.. 

 July 29, 1919. 

 Dec. 3, 1919. . 

 Oct. 12, 1919. 

 Nov. 8, 1917.. 



Number 

 taken 



2 

 4 

 6 

 19 

 2 



70 

 II 

 12 

 2 

 3 

 1 

 3 

 14 

 6 

 14 

 41 

 6 



