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<br />001757 <br /> <br />34 <br /> <br />tributary control actions would target the most harmful species using a variety of <br />methods. Monitoring of native and non-native fish species must be able to detect <br />changes in these populations that may result from management action, e.g., non- <br />native control efforts and the warming of dam releases. <br />(3) Use experimental dam releases to reduce mortality of young- of-year (YOY) <br />humpback chub leaving the LCR, particularly prior to operation of the TCD. These <br />actions may include releases that would impound the LCR during periods when <br />young humpback chub are leaving the LCR, stabilize habitat near the LCR <br />confluence, reduce non-native spawning and recruitment, displace or disadvantage <br />non-native fish, and maintain levels of turbidity that reduce feeding behavior of <br />sight feeders in the mainstem. Following construction of the TCD, the focus of <br />dam operations might change to improving spawning and rearing habitat for native <br />fish in the mainstem and controlling the spread of non-natives and parasites. <br />(4) Control parasites and diseases. Additiona.l monitoring and research is needed to <br />determine the level of infestation and to develop control methods. Warmer dam <br />releases may increase the spread or impact of parasites on humpback chub in the <br />mainstem. <br />(5) Use other management actions such as sediment/turbidity augmentation to <br />disadvantage non-native fish and provide cover for native species, invasive species <br />management plans, and impact reduction from scientific and recreational uses. <br /> <br />There is a risk of extirpation from catastrophic ,events in the LCR because it is currently <br />the principle spawning location for humpback chub in Grand Canyon and is occupied by much <br />of the population in a given year. Also, operation of the TCD and other management actions <br />intended to benefit the humpback chub carry the risk of unintended consequences that may <br />negatively affect the humpback chub population. <br />The top priorities to protect against such risks are (1) expand the range of the population <br />both above and below the LCR confluence (both mains:tem and tributaries) so that a catastrophic <br />event is less likely to negatively affect the population, (2) develop and implement an action plan <br />to alleviate threats that originate in the LCR watershed" and (3) establish a captive breeding <br />population for restoring the Grand Canyon population in case of extirpation. <br />A genetics management plan should be prepared that guides preservation of the genetic <br />diversity of the humpback chub in Grand Canyon. Dev1eloping a captive breeding population <br />needs to follow this peer-reviewed comprehensive plan as well as USFWS policy on controlled <br />propagation. Developing the broodstock should not compromise the viability of any extant <br />aggregations (i.e., it may be appropriate only to collect gametes or YOY from the mainstem <br />aggregations). Gametes, YOY, or adult fish may be collected specifically for a new captive <br />breeding population following the comprehensive plan and genetic analysis. The disposition and <br /> <br />GCMRC FY2006 Annual Work Plan (Draft February 15,2005) <br />