380 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



CHARACTER OF THE FISH FAUNA OF THE MISSOURI RIVER BASIN. 



The total number of species and subspecies of fishes at present 

 known from the Missouri Basin is 143. These are distributed among 

 24 families and 68 genera, as may be seen from the table on pages 

 426-428. This table also shows the distribution of the species among 

 the 9 different States of the Missouri Basin. It will be seen that the 

 great majority of the species do not extend westward beyond the eastern 

 counties of Kansas, Nebraska, and South Dakota. Only 55 of the 143 

 species are known from North Dakota, Montana, Wyoming, and Colo- 

 rado, and but 10 of these are limited to those 4 States. On the other 

 hand Missouri and the small part of Iowa drained by the Missouri fur- 

 nish 94 species, or, if we include the narrow-timbered and abundantly 

 watered strip of eastern Kansas, Nebraska, and South Dakota, we 

 have about 100 species occurring in this eastern or lower belt of the 

 Missouri Basin. 



The middle belt, or that portion lying between the one hundredth 

 and the one hundred and fifth meridians, has such characteristic species 

 as Platygobio gracilis, Hybopsis gelidus, RMnichthys cataractce duleis, 

 Hybognatlius nuchale evansi, and the like. Few if any of these are 

 confined to this belt, but they probably all extend more or less into the 

 lower and upper belts. 



The upper belt comprises the elevated mountain region where the 

 water is comparatively clear and cold. The characteristic species here 

 are the trout, whitefish, grayling, two or three species of suckers (P. 

 jordani, G. catostomus, and G. griseus), and the western blob. These 

 are all practically limited to this belt. 



In the lower belt is found the limit in the westward extension of spiny- 

 rayed fishes. West of the ninety-sixth meridian, which is approximately 

 the eastern boundary of Nebraska and the Dakotas, not over a dozen 

 species of spiny-rayed fishes are known to occur. This fact becomes 

 interesting when we recall that a single small creek in Indiana (Bean 

 Blossom Creek, Monroe County) is known to contain not fewer than 18 

 species of spiny-rayed fishes, and from the streams of Indiana alone 

 we know at least 51 species of that group, nearly as many as the total 

 number of species found in the entire fish fauna of the Missouri Basin 

 west of the ninety-eighth meridian. 



In the Missouri itself and in its larger tributaries are found such 

 large river species as Polyodon spathula, Scaphirhynchus platorynchus, 

 Leptops olivaris, Ictalurus punctatus, species of Ictiobus, and the like; 

 but in the smaller streams Gatostomus, Hybognathus, and Notropis are 

 the principal genera represented. Micropterus, Perca, Lepomis, and 

 Etlieostoma are not rare on the eastern edge of this region, but they 

 become more and more rare as we go westward and very soon disappear 

 altogether. Perca has not been found west of Dakota River (9S°30' W.) j 



