LAKE STURGEON. 767 



Adpev ler rupertianus, Eichakdson (1836), Fauna Bor.-Am., Fishes, 311, and of several 



authors. 

 Aoijpenser liopeliia, Gunther, Cat. Fishes Brit. Mus., vlii, 341. 



Description.— Snout rather short and blnntish, forming less than half the length of the 

 head in the aduJt, longer and more pointed in the yonng ; barbels long, nea'er the snout 

 than the eye ; bony shields moderate, rather smooth ; shields with the pointed keel 

 nearly central, and directed rather upwards than backwards; skin with numerous 

 prickles and stellate ossifications ; about 13 shields in the dorsal row (before dorsal fin) ; 

 34 in the lateral series and 9 in the ventral ; the plates beconiinj!; smoother with age, 

 and in very old t.[j(xim:jiis, most of them finally falling off; anal fin mcstly below the 

 dorsal ; caudal fulcra, not remarkably developed. Length, two to six feet. 



Habitat, Great L^ikes, Upper Mississippi and northward, very abundant in the Upper 

 Lakes, ascending the tributary rivers in large numbers to spawn in the spring. 



Diagnosis — The Lake Sturgeon is di'itinguishedfrom the S-a Sturgeon 

 (A. s'urio, L.), by its smaller size and the greater number of plates in the 

 lateral series (about 34 instead of 28). From the Ohio River Sturgeon, 

 it may, perhaps, be known by the central position of the spinous keel to 

 the plates. This character (first noticed by Professor Miloer), may be 

 simply due to the greater age of the specimens examined, as the plates 

 certainly grow smoother, and the spines more central with increased age. 



Habits — la Ohio this species occurs only in Lake Eiie and Us larger 

 tributaries, the Stu;gron of the Ohio River being considered, whether cor- 

 rectly or not, as belonging to another species. The following account is 

 abridged from the notes of Prof. Milner (Rept. Commr. Fish and Fisheries, 

 1872-73) : 



" This Stnryoun attains the largest size of any fish of the lakes. They are taken only 

 withiu coiiip_>.ratively shoal waters, and in some of the bays and among the islands they 

 are vory cbutidant. The largest specimen it has been my fortune to see did not quite at- 

 tain the length of six feet, though there are traditions in localities on the lakes of nine 

 foot Siurgpons. The average of the mature ones taken is less than five feet. In numbers 

 they will not compare favorably with any of the staple food-fishes. At Pandnsky, Ohio, 

 where they are more numerous than In any other locality, except, pf-rhaps, Green Bay, 

 Wis., tl.ere were abon,. 14,000 mature Sturgeons handled, weighing about 700,000 pounds, 

 obtained from about 85 pound-nets." 



Their f>:od consists almost entirely of the shell-fish of the lakes, prin- 

 cipally Gasteropods, the thinner-shelled kinds of the genera Fhysa, Planor- 

 bis, and Valvaia bv;ing found broken in the stomachs, while Limnma and 

 Melantho remain whole. Eggs of fishes are sometimes found, but it is 

 probable that they are not extensively spawn eaters. 



The spawning season in Lake Erie occurs in June. They then ascend 

 the \ariou.^ tributaiy rivers as far as the depth of the water and the 

 various obstructions will permit, in large schools, and may often be seen 



