Laserfiche WebLink
but peak spawning occurred between January and March (Bozek et al. <br />1984). Water temperature and photoperiod were declining toward <br />annual minima when razorback suckers first moved into spawning <br />areas. Peak spawning activity took place-when water temperature <br />was stable at 10 to 12 C (pers. comm., J. E. Brooks, U. S. Fish <br />and Wildlife Service) or was rising and in the range of 10 to 15 C <br />{Bozek et al. 1984). Water temperature reached 20 C by the end of <br />the spawning period in May (Bozek et al. 1984). Douglas (1952) <br />reported spawning temperatures of 12-18 C for razorback suckers in <br />Lake Havasu. <br />Male/female ratios of razorback suckers in Lake Mohave during <br />the spawning season ranged from 1.2 to 3.6:1 (Minckley 1983, Bozek <br />et al. 1984). Males generally outnumbered females on the spawning <br />grounds, and ripe males were present for a longer period than <br />females (Bozek et al. 1984). Bozek et al. (1984) reported that <br />during spawning peaks, about 80$ of the males and less than 65$ of <br />the females were ripe. Decreases in mean size of male and female <br />razorback suckers and catch rates of ripe individuals later in the <br />season (May) were noted (Bozek et al. 1984). Also, individual <br />razorback suckers were recaptured in spawning areas from one day <br />______ to one month after tagging, and indicated abbreviated residence <br />time at these locations. These data suggest that annual spawning <br />by the population occurred over several months, but that <br />individual razorback suckers completed spawning in a relatively <br />short time (Bozek et al. 1984). <br />36 <br />