Laserfiche WebLink
1 <br /> <br /> <br /> <br /> <br /> <br /> <br />,-,II <br />I'J <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />.~" <br />Razorback Sucker <br />Current Status and Recovery Efforts: The Lake Mohave population of <br />razorback sucker has been studied extensively (Burke et al. 1992, Buth et <br />al. 1987, Marsh 1994, Marsh and Minckley 1989, Minckley 1983, Minckley <br />e# al. 1989, 1991, Pacey and Marsh 2000). It represents the largest <br />population of razorback sucker in the lower basin with 4,000 wild <br />individuals still occurring there in 2003. These wild adults are expected to <br />disappear from the lake through natural mortality in the next decade <br />(Marsh pers comm.). However, 70,000 subadult razorback sucker have <br />been stocked into Lake Mohave by USBR and the Service since 1992 in <br />part as a result of section 7 consultations. These fish are beginning to <br />enter the population and replace the aging wild fish. The Lake Mohave <br />Native Fish Work Group, a group made up of State and Federal agencies <br />and university personnel, developed this stocking program. The goal of <br />the group is to establish an adult population of 50,000 fish using wild <br />larvae produced in take Mohave, to provide a genetic refugium for this <br />species in the lower basin. <br />Applicable Recovery Goals and Management Strategies: <br />Recovery Goal: Maintain genetic refugia in the lower basin and/or <br />self-sustaining population while moving towards recovery. <br />Downlisting Criteria: <br />1. Genetic variability of razorback sucker in Lake Mohave is <br />identified, and a genetic refuge is maintained over a 5-year period. <br />2. Two self-sustaining populations (e.g. mainstem and/or <br />tributaries) are maintained over a 5-year period, starting with the <br />first point estimate acceptable to the Service, such that for each <br />population: <br />a. the trend in adult (age 4+ ;> 400 mm TL) point estimates <br />does not decline significantly, and <br />b mean estimated recruitment of age-3 (300-399 mm TL) <br />naturally produced fish equals or exceeds mean annual <br />adult mortality, and <br />25 <br /> <br />