Lake Sturgeon 



most abundant in Lakes Erie and Ontario and least so in Lake 

 Superior, whose deeper, colder water is less favourable for its 

 growth than the more shallow, warmer water of the other lakes 

 named. The lake sturgeon is the largest and one of the most 

 important fishes of the Great Lakes, but it is now much less 

 abundant than formerly. The average length of the examples now 

 taken is less than 5 feet, though examples 6 feet long have been 

 occasionally taken, and rarely individuals 9 feet in length have 

 been reported. The average weight probably does not exceed 40 

 or 50 pounds, and about 100 pounds is the present maximum 

 weight. 



It delights to frequent comparatively shoal water where, accord- 

 ing to Milner, it feeds upon the smaller gasteropods, such as thin 

 shelled Physa, Planorbis and l/alvata, and the more firm Limnea 

 and Melantho. Though it is primarily a bottom feeder, it is known 

 that small fishes constitute a not inconsiderable portion of its food. 

 On August 9, 1894, Professor A. J. Woolman examined the stom- 

 achs of 55 sturgeon at Garden Island, Lake of the Woods, of 

 which number 28 contained one or more crawfish, 6 had insect 

 larvae, 6 had mollusks, and 22 were empty. Among the miscel- 

 laneous objects found were a fish-egg in one, a fish-vertebra in 

 another, a hazelnut in one, and gravel in eight! 



Head 3^; depth 5!; eye 9 to 10 in head; snout about 2; 

 D. 35; A. 26; dorsal shields n to 16; lateral shields 30 to 39; 

 ventral shields 8 to n. Body rather elongate; snout slender and 

 long in the young, becoming quite blunt with age, when it is 

 considerably shorter than rest of head; shields large, rough and 

 with strongly hooked spines in the young, becoming comparatively 

 smooth in old individuals; skin with minute spinules in many 

 series; ventral shields growing smaller with age, and finally decid- 

 uous; anal fin f length of dorsal, beginning near its middle. 



it 



