Lake Surgeon Acipenser rubicundus (Le Sueur) GENUS ACIPENSER LINNAEUS The lake sturgeon is found as an inhabitant of the Great Lakes and the larger rivers connected therewith, Lake of the Woods, and many of the Canadian lakes. It was formerly abundant in the upper Mississippi Valley and is still found in some numbers in the Mississippi and in the lower portions of the Ohio, Missouri, and its other large tributaries. It is now perhaps most abundant in the Lake of the Woods, where the annual catch in 1894 on the United States side amounted to 1,059,267 pounds. Since then the decrease has been very rapid, until in 1899 the catch was only 197,033 pounds. Among the Great Lakes it is 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, according to Milner, it feeds upon the smaller gasteropods, such as thin shelled Physa, Planorbis and Valvata, 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 stomachs 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 miscellaneous objects found were a fish-egg in one, a fish-vertebra in another, a hazelnut in one, and gravel in eight! Head 3 1/2; depth 5 3/4; eye 9 to 10 in head; snout about 2; D. 35; A. 26; dorsal shields 11 to 16; lateral shields 30 to 39; ventral shields 8 to 11. 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 deciduous; anal fin 2/3 length of dorsal, beginning near its middle.