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,. ~ ~ 11 <br />humpback suckers although ripe male and female flannelmouth suckers, <br />were obtained with relative ease. <br />It appears that spawning was also being attempted in the gravel ' <br />pit. When the ripe fish were being taken in the Colorado River, ripe <br />fish were also handled in the pit. Spawning appears to have been initiated <br />earlier in the pond as evidenced by spent females being captured there. <br />This is undoubtedly due to the more rapid warming of the pond than <br />the river. <br />Indications are- that the humpbacks-were spawning at the aaest end <br />of the pond in about 6 to 7 feet of water. We once captured 7 hump- <br />backs (2 loose females, 5 ripe males) rather close together in this area. This <br />corresponds with Douglas' (1952) description of their spawning in Lake <br />Havasu in the lower basin. Females, accompanied- by 2-12 males moved <br />along the shoreline until a suitable site was located and then began <br />the spawning act. Three fish tagged with ultrasonic transmitters remained <br />widely separated during this period and-thus gave no indication of <br />spawning congregations. <br />As mentioned earlier, the physical characteristics of the spawning <br />sites were quite similar. The bottom of all areas was characterized <br />by large cobble size rocks at depths of two to four feet. 4Jater velocities <br />averaged close to 3 ft. per second. <br />As the water continued to rise, raising the depths to G feet or <br />more over these sites, we no longer collected humpbacks or flannel- <br />mouths. The most probable explanation for this is that our sar~~pling gear <br />became rather ineffective at these depths.' Because of the turbidity <br />and swiftness of the water, any fish that we shocked were undoubtedly <br />carried downstream without being seen. <br />