200 







200 



100- 



0- — 

 100- 



600 



400 



200 



200 



400 



600 



LONGNOSE DACE 



LEOPARD DACE 



SPECKLED DACE 



2212 



50 100 150 200 250 281 



DISTANCE FROM MOUTH OF RIVER (KM.) 



Figure 17. — CPUE (catch per unit of effort) of longnose, 

 leopard, and speckled dace from the main stem of the 

 Yakima River in 1957 and 1958, by sampling site. 



fall to a pool in winter. In deeper pools 

 they may not be susceptible to electro- 

 fishing. 



Leopard dace (19) 



Normal range: Km. 120 to 169 (fig. 17, 

 table A- 12). 



Speckled dace (5) 



Normal range: Km. 24 to 80 and 113 to 

 281 (fig. 17, table A-13). 



Centers of abundance: Km. 56, 137,217, 

 and 250. 



Comn-ients: Speckled dace are abundant 

 in the main Yakima River and ex- 

 tremely so in irrigation canals where 

 flows are more moderate and stable. 

 Forty- three percent of all speckled 

 dace were caught in an irrigation out- 

 let at km. 217. 



Redside shiner (2) 



Normal range: Km. to 32 and 113 to 

 250 (fig. 18, table A- 14). 



Centers of abundance: Km. 120 to 177, 

 217, 225, and 250. 



Comments: Redside shiners are abun- 

 dant in the main Yakima River, espe- 

 cially above km. 120, and extremely 

 numerous in irrigation canals. 



1.200 



1.000 - 



50 100 150 200 250 281 



DISTANCE FROM MOUTH OF RIVER (KM.) 

 Figure 18. — CPUE (catch per unit of effort) of redside 

 shiner from the main stem of the Yakima River in 1957 

 and 1958, by sampling site. 



Chiselmouth X northern squawfish, hybrid 



Small catches were made at km. 169 and 

 below (table A- 15). This hybrid was also 

 taken during other studies from an irri- 

 gation canal that returns to the river 

 near km. 217 and at the Prosser bypass 

 trap (Patten, 1960). 



Redside shiner X speckled dace, hybrid 



Individuals of this putative parentage were 

 collected at km. 153, 209, and 258 

 (table A-16) and were frequently taken 

 during another study in an irrigation 

 canal that returns to the river near 

 km. 217. 



Bridgelip sucker (8) 



Normal range: Km. 8 to 72 and 113 to 

 250 (fig. 19, table A- 17). 



Largescale sucker (4) 



Normal range: Km. to 250 (fig. 19, 



table A- 18). 

 Period of abundance: Some indication of 



an increase in numbers in the spring. 

 Comm^ents: In the lower Columbia River 



during May, largescale suckers migrate 



13 



