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3.4 Discussion - Revisions to Stocking Plans Razorback sucker Inconsistencies were recognized between Colorado's and Utah's stocking plans: Utah's plan calls for stocking fewer fish/year (18,000 vs. 20,000) over fewer years (8 vs. 10) relative to Colorado's plan to achieve the same razorback sucker recovery goal target (5,800 adults + 30% buffer). Stocking plans need to be reconsidered in light of achieving adult demographic criteria in the recovery goals and because of subtle differences between Utah and Colorado as to when razorback sucker are considered to be adults. Age 4+ is given as the adult age in the recovery goals. Also, Colorado applies differeIlt buffers to different species and age-classes, and continues stocking to maintain three adult age-classes for 3 years. Differences in stocking plans appear to be related to the number of age-classes each calls for (3 vs. 5). Colorado stocks for 8 years (5 years to achieve three adult age-classes plus 3 additional years to maintain these age-classes for 3 years). Could be achieved in 7 years if adult razorback sucker are considered to be age-4+ t:: 400 mm TL). Plans need greater flexibility to allow stocking whenever fish reach 300 mm TL. Then fish could be harvested from grow-out ponds in the spring, reducing densities in ponds and allowing remaining fish to grow faster. Spring stocking in floodplains might enhance growth rates vs. stocking into main channel later in year. In the Green River, dispersal of razorback sucker is significant. With this wide dispersal, fish stocked in the lower Green River may end up in Lake Powell. Best spawning habitat is upstream; therefore, fish stocked in the lower Green River may not have easy access to the best habitat. Utah's objective of stocking razorback sucker in the lower Green River is to establish disjunct populations as a buffer against catastrophic mortality. Monitoring can be designed to address these uncertainties. Buffer should be set at 30% (i.e., average annual adult mortality). Higher buffers result in hatchery capacity being a limiting factor. Survival in grow out ponds is mr unknown variable. If survival exceeds expectations, "excess" fish could be stocked out, even if they exceed the stocking plan targets. Ouray National Fish hatchery needs 18 more acres of grow out ponds to meet current targets. Need to plan for hatchery facilities to meet targets, with any additional wetland production considered a bonus. We may be over-estimating survival of stocked fish. Monitoring will provide some answers, but they may not be timely to direct stocking plan development. Stocking plans do not account for reproduction of stocked fish. Utah's plan cuts off at 5 years because it anticipates reproduction of stocked fish at that point. Need to develop stocking targets based on differential survival rates, and adjust stocking rates as monitoring provides empirical survival data. If survival is less than expected, it may be too late to increase hatchery capacity to meet revised stocking rates. Therefore, it is better to develop 9