GREAT LAKES COREGONIDS 



533 



individuals of either sex were not often seen maturing under 320 millimeters in length. 

 These fish weigh about 1 pound in the round. Maturing of the sex organs in small 

 fish was observed in Batchawanna specimens, though Frank La Pointe, who fishes 

 there, says the fish run large and seldom spawn under 3 pounds. Specimens from 

 Marquette, Mich., between the lengths of 300 and 348 millimeters, were not approach- 

 ing maturity. Nothing is known of the size at maturity at other places. 



ABUNDANCE 



What has been said about the abundance of the whitefish in Lake Michigan 

 applies with equal force to Lake Superior and the other Great Lakes. Whitefish are 

 now common nowhere, and the lake's entire production for 1922, the last year for 

 which complete census figures are available, amounted to about 680,000 pounds, as 

 compared with 4,191,000 pounds reported in 1890. The bays and shoals around the 

 various islands are the last strongholds of the species, and the quantity of the pro- 

 duction in these areas fluctuates from year to year. In some such areas, when the 

 species has been so reduced that commercial operations are no longer profitable, the 

 economically enforced respite from persecution probably enables the species to increase 

 in numbers again. The Whitefish Point grounds, the most famous on the lake, 

 now, however, are believed to have been entirely depleted for many years. 



Coregonus clupeaformis of Lake Nipigon 



The whitefish of Lake Nipigon closely resembles that of Lake Michigan. There 

 are a few differences, which are apparent from a comparison of the main systematic 

 characters capable of numerical expression listed below: 



Gill rakers on the first branchial arch : 



Michigan, (24) 26-28 (30). 73 



Nipigon, (26) 27-29 (30) » 

 Lateral-line scales: 



Michigan, (74) 81-88 (93). 75 



Nipigon (76) 78-85 (89). 

 L/H: 



Michigan, (4.2) 4.4-4.8 (5.3). 78 

 Nipigon, (4.1) 4.3-4.5 (4.8). 

 H/E: 



Michigan, (3.8) 4-4.4 (4.8). 

 Nipigon, 3.9-4.3 (4.7). 



H/S: 



Michigan, (3.2) 3.4-3.7 (4.1). 

 Nipigon, (3.2) 3.4-3.7 (4.1). 



The figures show no conspicuous differences between the two forms, and it is 

 likely that, if more specimens of comparable size were studied, the apparent ones might 

 disappear. There is a possibility that the maxillary may be found to be proportionally 

 longer in the Nipigon form. 



" One hundred and fifty-one specimens. 



B These and succeeding figures for Lake Nipigon, except those for H/E, are based on an examination of 34 specimens ranging in 

 length from 203 to 409 millimeters. The H/E figures are given for 25 specimens 300 millimeters or less in length. 

 « One hundred and ninety-one specimens. 



" These and succeeding figures for Lake Michigan, except those for H/E, are based on an examination of 126 specimens rang- 

 ing in length from 179 to 483 millimeters. The H/E figures are given for 74 specimens 300 millimeters or less in length. 



H/M: 



Michigan, (3) 3.2-3.4 (3.8). 

 Nipigon, (2.8) 3-3.3 (3.6). 

 Pv/P: 



Michigan, (1.5) 1.7-2 (2.3). 

 Nipigon, (1.5) 1.6-1.8 (2). 

 Av/V: 



Michigan, (1.3) 1.5-1.8 (2). 

 Nipigon, (1.2) 1.5-1.6 (1.7). 

 L/D: 



Michigan, (3.3) 3.9-4.3 (4.8). 

 Nipigon, (3.1) 3.5-4 (4.2). 



