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<br />, <br />~"..' <br /> <br />successful Colorado squawfish reproduction does occur when conditions are <br />favorable in the river as was evidenced in 1987 and 1988 surveys. Young-of- <br />the-year Colorado 5quawfish are usually captured in shallow backwaters or side <br />channel habitats with silt and sand substrates and little or no current. <br /> <br />C':) <br /> <br />C.~} <br />""'" <br />~ <br />~ <br /> <br />Adult Colorado squawfish use a variety of habitat types. which vary depending <br />on time of year. They use shoreline run, eddy, and backwater habitats during <br />pre- and post-runoff periods and backwater areas or flooded riparian areas <br />during peak runoff. A natural hydrograph with a large spring peak with a <br />gradually declining/descending limb into early summer, and low, stable flows <br />through summer, fall and winter are thought to create the best habitat <br />conditions for endangered fishes. <br /> <br />Adult razorback suckers are normally found in a variety of habitats including <br />quiet eddies. pools, and mid-channel runs. They are usually found over a sand <br />or silt substrate but can also occur over gravel and cobble bars in the spring <br />during spawning. Razorback suckers have been collected recently in the San <br />Juan River arm of Lake Powell and near Bluff. Utah in the proximity of some <br />irrigation ponds connected to the river by a canal. Spawning appears to be <br />taking place in Lake Powell. but recruitment of young-of-the-year razorbacks <br />has not been documented. <br /> <br />On-going studies regarding the relative abundance of endangerd fishes, other <br />native fishes and exotics will be continued under the recovery program. <br />Reproduction and recruitment, if any. will be documented and used to evaluate <br />the need for artificial propagation discussed in section 3.6.3. <br /> <br />3.6.3 Assessment of the Need for Auqmentinq Existinq Stocks <br /> <br />If results of the fish density and reproduction/recruitment studies indicate <br />the need for population augmentation. the San Juan Recovery Implementation <br />Program will include the reintroduction of rare species. Along with the <br />introductions, studies will be conducted on migration patterns, <br />imprinting/homing, spawning, survival. reproduction, interaction with wild <br />populations. and habitat use. Any production of squawfish or razorback sucker <br /> <br />30 <br />