460 



BULLETIN OF THE BUREAU OF FISHERIES 



Mandible 



Length 



30 fathoms 



60 fathoms 



35-50 

 fathoms, 

 Cheboy- 

 gan 



Harbor 

 Beach 



Alpena 



Total 



Alpena 



Georgian 

 Bay 



Total 



Longer than upper 



Equal to upper 



27 

 64 



62 

 99 



89 

 163 



240 

 23 



149 

 20 



389 

 43 



38 

 40 



The deep-water fish appeal to have a proportionally larger head, longer paired 

 fins (especially ventrals), and a longer mandible than those from the shallower 

 waters. In most cases the 35-50 fathom group conforms to neither of the two but 

 appears often to be intermediate, as might be expected. Whether specimens from 

 30 and 60 fathoms are always, at all seasons, so characterized is not known, and it is 

 quite probable that there is a migration during the year of all schools of bloaters over 

 a considerable bathymetric range, so that the fish taken throughout the season at a 

 definite depth might very conceivably be of several schools. 



The bloaters taken from the various ports on the lake agree, in the systematic 

 characters examined, with one or the other of the two groups compared above, so 

 that there is no evidence so far that there are geographical races in the lake. 



Size variations. — Only nine specimens over 200 millimeters in length have been 

 collected, and therefore the usual size groups can not be compared. It is not likely, 

 however, that the changes correlated with growth are different for this form than for 

 other Leucichthys in the lakes. 



Specimens 110 millimeters long usually have been found to show maturing sex 

 organs. 



COMPARISONS 



Hoyi is most like Tciyi and young artedi. A discussion of the differences between 

 hoyi and Tciyi is given on page 440. 



From the small artedi the bloater is distinguished by its less elongated and more 

 bloated body shape, fewer gill rakers on the first branchial arch, fewer scales in the 

 lateral line, and relatively longer head, eye, maxillary, and paired fins. These 

 characters, excepting the first, are compared below: 



Gill rakers on the first branchial arch: 



hoyi, (37) 40-43 (47), al with 2 per cent more than 44. 



artedi, (40) 45-50 (53), aa with 89 per cent more than 44. 

 Lateral-line scales: 



hoyi, (63) 68-76 (84), with 12 per cent more than 76. 



artedi, (68) 76-86 (98) , 22 with 86 per cent more than 76. 

 L/H: 



hoyi, (3.5) 3.8-4.1 (4.5), with 13 per cent more than 4.1. 

 artedi, (4) 4.2-4.5 (4.8), with 89 per cent more than 4.1. 



21 The figures in this section for hoyi (except for H/M and H/S, which are given for 58 speijimens) are based on an examination 

 of 907 specimens ranging between 79 and 221 millimeters in length. 



22 These figures for artedi are given for 308 specimens ranging in length from 125 to 371 millimeters. Figures not so marked are 

 based on an examination of 135 specimens between the lengths of 125 and 225 millimeters. 



