GREAT LAKES COREGONIDS 



541 



L/H: 3.7 3.8 3.9 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5 5.1 



All lakes .- __ 2 6 16 31 41 48 44 17 8 1 



Aquarium 2 1 1 __ 1 3 3 4 7 7 1 2 __ __ __ 



H/E: 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 



All lakes __ .-.- 4 5 23 25 31 42 45 30 5 2 1 1 



Aquarium 2 1 3 5 3 6 4 3 ... 3 .. 1 ______ __ 



H/M: 2.8 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 



All lakes 1 2 22 48 40 45 30 13 5 5 



Aquarium 2 5 7 9 4 3 ______ ____ 



H/S: 2.9 3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1 4.2 4.3 4.4 



All lakes -- .. -- 6 17 17 32 36 28 31 23 8 5 ._ 1 



Aquarium 1 .. 2 5 4 9 8 1 .. 2 __________ __ 



Pv/P: 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 2.3 



All lakes .. 2 8 19 33 44 36 45 18 4 2 



Aquarium 3 3 11 8 4 2 ._ 1 ____ __ _. 



Av/V: 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 



All lakes __ 2 8 58 71 46 24 7 



Aquarium 1 1 1 2 5 9 11 1 __ __ 



Gill rakers: 23 24 25 26 27 28 29 30 31 34 



All lakes 2 35 136 172 180 79 15 3 __ 



Aquarium 5 7 8 5 3 2 ...... 1 



It is clear that the artificially reared specimens have a proportionally longer head, 

 eye, maxillary, snout, and paired fins, and fewer gill rakers than naturally reared 

 fishes. (The one fish with 34 rakers (223 millimeters long) is probably a "mule 

 whitefish.") 



Aquarium conditions thus have produced or permitted the development of individ- 

 uals that are strikingly different from those that are found in nature. Even char- 

 acters that are considered generic, such as the position of the premaxillaries, have been 

 altered. These observations are of especial interest in view of the striking differences 

 that have been found to obtain in certain species of Leucichthys between forms of a 

 species group. 



Coregonus clupeaformis of Lake Ontario 



The whitefish of Lake Ontario resembles that of Lake Michigan. The princi- 

 pal characters of the two forms are compared below: 



Gill rakers on the first branchial arch: 



Michigan, (24) 26-28 (30) . 79 



Ontario, (25) 27-28 (31). 80 

 Lateral-line scales: 



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



Ontario, (75) 80-88 (92). 

 L/H: 



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

 Ontario, (4.4) 4.6-4.9 (5.2). 

 H/E: 



Michigan, (4.4) 4.6-4.9 (5). 

 Ontario, (4.2) 4.7-5 (5.3). 

 H/M: 



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



Ontario, (3) 3.2-3.4 (3.7). 



Figures for Lake Michigan, except those for gill rakers, lateral-line scales, and H/E, are based on an examination of 126 speci- 

 mens ranging in length from 179 to 483 millimeters. The H/E figures are given for 52 specimens between the lengths of 300 and 

 483 millimeters, those for gill rakers for 151 specimens, and those for scales for 191. 



80 These and other figures for Lake Ontario, except those for lateral-line scales and H/E, are based on an examination of 39 

 specimens ranging in length from 253 to 444 millimeters. The H/E figures are given for 27 specimens over 300 millimeters long, 

 and the scale figures have been supplemented by counts of 160 specimens, not preserved, from Brighton, Ontario. 



H/S: 



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

 Ontario, (3.3) 3.6-3.8 (4.2). 

 Pv/P: 



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

 Ontario, (1.4) 1.7-2 (2.2). 

 Av/V: 



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

 Ontario, (1.3) 1.6-1.8 (1.9). 

 L/D: 



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

 Ontario, (3.4) 3.7-4 (4.3). 



