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<br />DRAFr AND PREDECISIONAL DOCUMENT. FOR COORDINATION COMMmEE REVIEW ONLY <br /> <br />.") <br />.:> <br />.-.:> <br />') <br />~ <br />Q.'J <br /> <br />4.3 IDENTIFY AND MANAGE THE NATIVE FISH COMMUNITY OF THE <br />SAN JUAN RIVER BASIN TO RESTORE THE ENDANGERED FISH <br />SPECIES <br /> <br />Protection and long-term management of the native fish community is best accomplished through <br />an approach that emphasizes an evaluation of historic and current community structure dynamics. <br />Specifically, identification of the spatial and temporal distribution and abundance patterns of the <br />native fish species relative to man-caused alterations of the San Juan River is the focus of this <br />objective. In concert with research activities on physical environmental changes, fish community <br />data will provide necessary guidance for selection and implementation of management activities. <br /> <br />Paramount to identifying the level of recovery possible for the native fish species is the <br />characterization of the historic fish populations, including species diversity and abundance. To <br />gain a better understanding of the changes from historic to current conditions, identification of <br />the status and trends of native fish species is necessary. Specific research activities are designed <br />to address the response of the current fish community to various flow regimes. particular <br />emphasis will be placed upon the response of the native and non-native fish species to various <br />Navajo Reservoir releases. The life history of the endangered fish species will be determined <br />within practical limits. Movement and habitat use patterns, reproductive habits, and young-of- <br />year and juvenile distribution and occurrence will be emphasized. Efforts will be made to <br />determine the response of the endangered fish species, including abundance and distribution, to <br />flow regimes. <br /> <br />While efforts have been rnade to address fish health concerns in cultural and refugial <br />environments, minimal attention has been given to determining fish health issues in wild <br />populations. Studies of the San Juan River fish community have documented the widespread <br />occurrence of external physical abnormalities. Initial results have indicated that bacterial <br />infections, presumably due to environmental stresses, are adversely affecting fishes. Additional <br />studies will be conducted to determine the identity, extent, and causes of fish health problems <br />in the San Juan River. <br /> <br />Studies are underway to evaluate the genetic distinctiveness of San Juan River populations of <br />Colorado squawfish and razorback sucker. These studies will be incorporated into any decision <br />regarding the necessity for establishment of refugial populations or gene banks. If deemed <br />necessary plans will be developed and implemented to protect the genetic resources of the <br />endangered fish species. The need for an augmentation effort to restore or improve the status <br />of endangered fish species will be determined and implemented. Currently, a captive-bred stock <br />of razorback sucker from the San Juan River Arm of Lake Powell is maintained in a refugia. <br />A portion of these fish are being used in field studies to delineate life history attributes of the <br />species. These data will be used to determine the feasibility, utility, and type of augmentation <br />necessary to assist in recovery of razorback sucker. Similar efforts for Colorado squawfish will <br />be considered and evaluated, without interference with ongoing research activities on the species. <br /> <br />8 <br />