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2) Some benefit to this population could be achieved by boosting the annual adult <br />survival rate. An increase from the current 0.86 to 0.90 would result in a doubling of <br />the population in 18 years. Four sources of mortality that might be reduced through <br />management activities include: <br />a) Stranding of adults in gravel pit ponds after spring runoff. Gravel pits <br />located in the floodplain should be made to drain with descending flow or <br />sufficiently diked to exclude flood waters and squawfish. <br />b) Angler-related mortality. Increase law enforcement and information and <br />education programs, especially in the Grand Valley. <br />c) Choking mortality from ingestion of channel catfish. Reduce numbers of <br />riverine channel catfish by whatever means feasible. r <br />d) Biological sampling mortality. Use only approved electrofishing equipment <br />and procedures. Limit time trammel nets are set to 15 minutes. Train <br />biologists in proper handling and holding procedures, and implantation <br />techniques for radio-tags and PIT tags. <br />3) Conduct research to identify the relationship between environmental variables and <br />annual reproductive success and survival of young in the Colorado River. Results <br />from such studies would provide the guidance needed for implementing effective <br />management activities that could boost recruitment rates. <br />4) Boost the recruitment rate by implementing appropriate management activities. If the <br />average annual recruitment rate was doubled, the population could double in size in <br />5-6 years; in 18 years it could be 10 times the size it is today. This assumes the <br />long-term recruitment rate now balances the mortality rate, i.e., 14 % and recruitment <br />is doubled to 28% while maintaining the current mortality rate. Average annual <br />recruitment rate could be doubled by increasing the frequency of strong cohorts from <br />once every 10 years to once every five years. Such population increase would <br />necessitate the availability of adequate adult habitat. <br />5) Conduct bioenergetics studies to estimate how many adults the river can presently <br />support and could potentially support with the implementation of appropriate <br />management activities. Such estimates would provide the basis for recovery goals. <br />viii