516 



BULLETIN OF THE BUREAU OF FISHERIES 



The whitefish was described originally from a specimen taken in St. Marys 

 River below the falls. The type is not known to exist. 



The whitefish is distributed generally throughout the Great Lakes. It is the largest 

 and most valuable of the coregonids. The maximum size attained varies with the 

 locality, but from the most favorable areas individuals have been reported weighing 

 26 pounds or more. Such large fish are now rare everywhere. In most of the lakes 

 the largest fish now caught weigh 8 or 10 pounds, and but few examples so large are 

 obtained annually. The species inhabits by preference the shallower water and 

 spawns in late fall. In all of the bodies of water except Erie and Ontario the white- 

 fish races are quite similar in appearance. Those from Lakes Erie and Ontario tend 

 to have proportionally deeper bodies, and the Erie race is distinguished further by 

 having, on the average, lewer lateral-line scales and probably fewer pectoral rays and 

 scale rows. 



A description of the Lake Michigan form is given as typical for the sake of uni- 

 formity of arrangement of the various sections of the text, most of the other types 

 of Great Lakes coregonids having originated in that lake. The whitefish of Lake 

 Huron, which the St. Marys River fish probably most nearly resembles, is, moreover, 

 virtually identical in its characters with the whitefish of Lake Michigan. 



Coregonus clupeaformis of Lake Michigan 



The body is compressed, fusiform, and -rather elongate, with its greatest depth 

 through a point just in front of the dorsal. This dimension varies considerably, but 

 for specimens under 40 centimeters in length it is contained (3.3) 3.9-4.3 (4.8) 65 

 times in the total length. Larger fish, especially the females, certainly would aver- 

 age deeper. From the occiput the dorsal profile curves upward to the insertion of 

 the dorsal fin. In specimens up to about 23^ pounds in weight (about 420 milli- 

 meters long) the rise of this curve is even and gradual, but in larger specimens its 

 cranial half rises more rapidly than the caudal, while the caudal half continues with 

 little further elevation. Thus, the predorsal profile becomes more convex in large 

 fish, wherefore the fishermen often call them "bowbacks." The base of the dorsal 

 usually is somewhat inclined caudally toward the lateral fine. It often lies below 

 the general level of the back. The contour line between the dorsal and the adipose 

 is nearly straight. The ventral profile descends in a gentle curve from the tip of the 

 mandible to the ventrals and then rises in a sharper curve to the caudal peduncle. 

 The head, viewed from the side, is relatively small and of little depth and varies in 

 shape from obtuse triangular to acute, according to the shape of the snout. Its 

 length is contained (4.2) 4.4-4.8 (5.3) times in the length of the fish. Its dorsal 

 profile varies from a nearly straight line to a faint double curve. In the latter case 

 the curve is convex from the tip of the snout to a point above the caudal margin of 

 the eye and concave from the latter point to the occiput. The convexity of the 

 anterior dorsal contour is often very pronounced in large individuals. The ventral 



es These and succeeding figures (unless otherwise marked) are based on an examination of 126 specimens ranging in length from 

 179 to 483 millimeters. All but two of these are less than 2 pounds in weight, such specimens having been selected for reasons o 1 

 economy and convenience. In the proportional values given for these specimens, therefore, it should be borne in mind that larger 

 specimens may regularly have values, particularly for L/H and H/E, that will not fit in the usual range of these values given for 

 the smaller fish, and which may even fall outside the extremes here recorded. The changes accompanying growth are considered 

 in a succeeding paragraph. 



