FAMILY ACIPENSERIDAE 77 



young are usually dark olive above and paler with dark blotches on the 

 sides; the adults are greenish olive or reddish and without spots. They 

 commonly attain a length of 6 feet in Lake of the Woods, but what is 

 probably the record sturgeon for this lake was procured off Long Point 

 in June 191L It weighed 236 pounds as caught and 120 pounds dressed 

 and was about 8 feet long. 



Rock sturgeon range through the drainages of the Red River of the 

 North. Hudson Bay, and the St. Lawrence, and southward in the Mis- 

 sissippi drainage to northern Alabama and Missouri. They are a shoal- 

 water fish occurring both in streams and lakes. In Lake Superior they 

 are seldom if ever taken in the deep waters along the Minnesota shore 

 but are said to be common in the comparatively shallow waters of 

 Keweenaw Bay and in the vicinity of the Apostle Islands. They are 

 occasionally taken in St. Louis Bay. 



Rock sturgeon formerly occurred in some abundance in the Upper 

 Mississippi River but are now becoming scarcer each year. In Minne- 

 sota they have been reported from Minneapolis (Cox, 1897) , the St. 

 Croix and Kettle rivers and Lake Pokegama in Pine County, and from 

 Lake Pepin (Wagner, 1908), Red Lake River at Crookston (Surber, 

 1920), Red Lake, Lake of the Woods, and Rainy River and its tribu- 

 taries. At present (1939) , thanks to protective laws, rock sturgeon are 

 increasing in the Snake, Cross, and Kettle rivers and in Pokegama Lake. 

 Greene (1935) reported them from Lake Pepin, the Wisconsin River, 

 and several localities in the Lake Michigan drainage. Occasionally stur- 

 geon are caught on hooks but they are usually caught in pound nets 

 and gill nets. 



Rock sturgeon are said to frequent the shoal waters of lakes by prefer- 

 ence and to ascend streams in the spring to spawn, but there are excep- 

 tions at Lake of the Woods. In 1911 they frequently spawned about 

 some of the rocky islands not far south of Kenora (Surber) , but their 

 favorite spawning grounds were formerly at the Soo Rapids on Rainy 

 River, to which point they at one time ascended in great numbers each 

 spring at about the time the ice broke up. Spawning migrations have 

 been noted as early as April 5, and they often last until the middle of 

 June. At spawning time sturgeon are frequently seen in shallow water. 

 Each spring in May and early June hundreds of sturgeon pass from the 

 St. Croix River up the Snake River and gather under the dam at Cross 

 Lake. The eggs are sticky and adhere to sticks and stones. The young 

 at a length of three-fourths of an inch start feeding on Entomostraca 

 or minute Crustacea and continue this diet until they are 7 to 8 inches 

 long. 



Sturgeon are bottom feeders, their proctractile mouths being well 

 fitted for sucking in the small animals and plants on which they feed. 

 Their food consists principally of fresh-water snails, crawfish and insect 



