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<br />I . .~~ ,:: f ~ '\ <br />',l ... ,p 'oJ <br /> <br />Probably the most important judgment call that needs to be made soon in relation to humpback <br />chub is whether to abandon planned testing of various simple options for improving juvenile <br />survi val in favor of treating the evidence of recent spawning stock decline as an "emergency" <br />warranting simultaneous application of a whole suite of mitigation measures (TCD, hatchery <br />supplementation, etc.). Straight-line extrapolation of the recent trend estimates would imply a <br />significant risk of extinction for the LCR spawning population within the next 10-15 years. <br />However, this prediction is not supported by estimates of recruitment rates of 2-year old fish. <br />Those rates appear to have been relatively stable since the early 1990s, though at considerably <br />lower levels than would be needed to maintain the spawning population at 1989 levels. If <br />recruitments continue to be stable, we predict that the spawning population will soon stop <br />declining, and will stabilize at an average spawning abundance of roughly 50% of its current <br />level, and that average will most likely be between 1000 and 2500 fish (Figure 7). That is, the <br />assessment data do not in fact support demands for emergency policy actions. In terms of <br />present, (and almost certainly continuing) uncertainty about the stock size estimates, it is hard to <br />imagine picking a worse target or goal to try to confirm or deny than the current recovery goal of <br />2000 fish. Given existing investments in stock assessment data gathering, there is almost no <br />chance that we will be able to say confidently whether or not this goal has been exceeded over <br />the next decade, unless there is some really dramatic and obvious change in recruitment rate. <br /> <br />So what should he done.. ... ? <br /> <br />Stay the present course of experimental actions using reasoned responses and treatments to <br />inform future decisions. Be active about policy experimentation to promote learning and reduce <br />uncertainty while simultaneously developing contingency plans for 'emergency' actions. Then <br />use this toolbox of actions as an attempt to thwart extinction of this population in the next few <br />years if further decline and lack of stability in the population becomes more apparent. A number <br />of these actions, e.g. rearing young of the year fish in a hatchery or in another tributary as a <br />refugia population, could be implemented sooner rather than later without materially affecting <br />our ability to 'learn' about responses to management actions. <br /> <br />Draft - April 21, 2003 <br /> <br />6 <br />