162 REPORT OF STATE GEOLOGIST. 



In Indiana it has been taken in the Wabash River from Vigo County 

 to New Harmony (3, II, 156;, 2S, 1888, 55); Lake Michigan and Ohio 

 River (9, 1874, 228); New Harmony (4, 1888, 42). Milner reports it 

 abundant in Lake Michigan. It also occurs in the Ohio River. The 

 specimens taken there were formerly regarded as belonging to a distinct 

 species, but authors now consider them as less mature individuals. Prof 

 Milner regards the sturgeon as occupying the zone in the Great Lakes 

 extending from shore to a depth of twenty fathoms. Michigan City (1, 

 1889, 253). 



Prof. Milner (11, 1872-73) says that at the southern end of Lake 

 Michigan these fishes begin to congregate early in June, near the shores 

 and mouths of rivers for the purpose of depositing their spawn. Some 

 taken at the mouth of the Calumet River on the first of July were emac- 

 iated, and only one in twenty contained spawn. 



The eggs, and probably the very young, are preyed upon by other 

 fishes. Some sturgeons even have been found with sturgeons' eggs in 

 their stomachs. Prof. Milner does not" think that the sturgeons, except 

 the youngest, are greatly exposed to the attacks of other fishes. When 

 small, they are so well defended by the sharp spines of their bony shields 

 that they would make an uncomfortable mouthful for any fish of the 

 lakes ; while, after the spines have disappeared, the sturgeon has become 

 too large for any fish to attack. Lampreys, however, fasten on them 

 and produce sores and ulcerations. 



The food of the' sturgeon consists of small mollusks. Those with thin 

 shells have these broken up ; the thicker ones remain unbroken. They 

 are also extremely fond of cray- fishes. They are not to any great extent 

 eaters of fish spawn. Prof. Milner says that the sturgeon as food is not 

 popular. Many of the fishes are taken in nets along the lakes and then 

 thrown out and allowed to decay, in order that they may not get into the 

 nets again. The French Canadians make a kind of soup of the sturgeon, 

 which is palatable, resembling chicken soup. A considerable quantity of 

 smoked sturgeon is prepared. Caviare is made out of the eggs, while the 

 skin is stated to be capable of being converted into a valuable leather. 



Dr. H. M. Smith, writing later than Prof Milner (4, 1892, 185), 

 states that the value of the sturgeon is yearly becoming more fully appre- 

 ciated, so that, the fishermen now receive the same price for it as for 

 white-fish and lake trout. The sturgeon is captured mainly by means of 

 gill-nets. 



Dr. Ryder (4, '88, 234) has studied the sturgeons. During their larval 

 stage they possess teeth. When hatched, the young sturgeon is barely 

 half an inch long. Their earliest food probably consists of microscopic 

 organisms. Later DapJmicke and Cladocera are preyed on. Then the 

 larger Crustacea are sought after, Amphipods and Isopods. A good deal 



