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<br />generally includes adding salt (19 g/gallon), Stress Coat (1 mUgallon), and other <br />chemicals such as Furacin (C. Fiegel, USFWS, pers. com.). <br /> <br />We suggest direct transport via helicopter to the appropriate receiving facility. Since <br />several hundred to several thousand fish will be transported (numbers are discussed <br />below), this will likely require several long distance flights per year just for fish transport. <br />Two large coolers, each containing from 300 to 400 age-O fish, and supplied with <br />oxygen should be the maximum expectations for transport. More preferable would be <br />one cooler transported per flight, with a technician on board to monitor oxygen levels. <br /> <br />In summary, we recommend capturing fish at age-O (50-70 mm), from multiple localities <br />within the LCR during the months of July and August. <br /> <br />What is the best size to grow out captive fish before release? <br /> <br />We recommend that fish are grown out to a minimum of 150 mm for initial efforts. <br />There is consensus that it is imperative to have the ability to monitor the released fish. <br />Fish ~ 150 mm can be PIT tagged, and individually tracked with ongoing monitoring <br />efforts once released into the wild. <br /> <br />Whereas age-O humpback chub show minimal growth at 10 oC (Gorman and <br />VanHoosen 2000), once humpback chub reach 150+ mm, they will grow in mainstem <br />waters (Valdez and Ryel 1995). For example, monthly growth rates of 2.25 mm, and <br />2.79 mm were calculated for mainstem fish between 150 to 200 mm, and between 200 <br />to 250 mm, respectively (Valdez and Ryel 1995). In contrast, monthly growth rates of <br />1.42 mm and 1.33 mm were calculated for 150 to 200 mm, and for 200 to 250 mm fish <br />in the LCR (Minckley 1992). This discrepancy may not be real, or it could be that once <br />fish reach 150+ mm, there is more food available in the mainstem, allowing faster <br />growth even at lower temperatures. <br /> <br />Whether to grow fish beyond 150 mm becomes a question subject to debate. Larger <br />humpback chub (>150 mm) should be even less prone to the effects of predation by <br />nonnative fishes (Valdez and Ryel 1995), and to the detrimental effects associated with <br />cold, fluctuating river flows (Clarkson and Childs 2000). Wild fish that are 200 mm are <br />estimated to have a greater annual survivorship than wild fish at 150 mm (Table 1). <br />Note that to obtain even a 52% annual wild survival rate, fish would need to be 134 mm. <br />Therefore, fish grown to 150 mm could optimally have a post-release annual survival <br />rate of -55%, while fish grown to 200 mm could have an optimal post-release annual <br />survival rate of 67% (Table 1). <br /> <br />Unfortunately, the above survival rates are likely highly optimistic since they are <br />estimated wild survival rates. Actual survivorship rates of released fish grown in <br />captivity will likely be much lower. For example, for salmonids, typically less than 5% of <br />all hatchery-reared fish make it to adulthood (McNeil 1991). For other species released <br />from hatcheries, the number is commonly lower (e.g., chum salmon 1-3%, and cod <br /><1 %; Salvanes 2001). Low returns for hatchery-reared trout have been reported for <br /> <br />27 <br />