YCT Multi-state Assessment 



February 10,2003 



Table 4. Look-up table for types of barriers to fish movement upstream. 



Barrier Type 



Water diversion 



Fish culture facility/research facility 

 Temperature 



Bedrock 



Culvert 



Debris 



Insufficient flow 

 Manmade Dam 



Pollution 



Beaver dams 



Unknown 



|Velocity barrier 



Waterfall 



Table 5. Look-up table for extent of blockage caused by barriers. 



Table 6. Look-up table for barrier significance. 



Barrier Significance 



Prevents introgression 



Prevents ingress of competing species 

 Migration barrier 



[Temporary, but presently prevents introgression 



[n/a 



[unknown 



Current Distribution and Genetic Status 



Lower and upper bound of all stream segments presently occupied by naturally self-sustaining 

 populations of YCT will be located and data quality associated with the locations of these 

 boundaries of current distribution will be rated (DQI; Tables 1 and 2). Genetic infomiation and 

 status will be rated for each YCT mapping unit (Tables 7 and 8) along with their DQI. For Table 

 7, base the category determination on information from the largest sample and/or the most recent 

 sample. Naturally self-sustaining populations are the only ones that will be assessed in this status 

 review. Relative abundance for each YCT mapping segment will also be rated (Table 9). 



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