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37 <br />Table 8. Physical characteristics of spawning sites in the Yampa River <br /> used by razorback and flannelmouth suckers, 1975. <br />Date Locationa Turbidity Temperature Velocity Depth <br /> (JTUs) (C) (m/sec) (m) <br />1 May site A - 7 0.92 0.83 <br />3 May site A 350 12 0.92 0.83 <br />11 May site A 500 15 0.92 0.83 <br />14 May site A 700 16 0.89 1.00 <br />19 May site B 2000 10 0.95 0.67 <br />a Locations of spawning sites are indicated in Figure 7. <br />Walker Wildlife Area. Seven razorback suckers (two ripe females and <br />five ripe males) were captured at the west end of the pond in one <br />trammel net set overnight. These fish were probably cruising the <br />shoreline during spawning as described by Douglas [1952]. The shore- <br />line was composed of cobble (similar to the bars in the main river) <br />and was regularly agitated by wave action. Temperatures ranged near <br />17 C at this time, while turbidities were approximately 100 JTUs. No <br />evidence of successful reproduction of any native fish was found in <br />the gravel pit during 1975. This may be attributed, at least in part, <br />to the large numbers of introduced predaceous fish (i.e., largemouth <br />bass, green sunfish and channel catfish) present in the pit. <br />Fecundity <br />Because the razorback sucker is rare, no fish were sacrificed to <br />determine fecundity. However, fish already in the collection at Utah <br />State University were examined for maturity and fecundity. These