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Summary

Monitoring data from 2000 were generally consistent with typical results from previous years. The distinction between upper pools (Pools 4, 8, and 13) and lower areas (Pool 26, Open River Reach, and La Grange Pool,) was again evident in the abundance of submersed vegetation and invertebrates. This suggests that turbidity and the availability of off-channel habitats may be important systemic features affecting biotic production at lower trophic levels. Areas with higher abundance of plants and invertebrates tend to support increased abundance of waterfowl and fish. An important question for management is, can we increase the amount of off-channel habitats in the lower pools or can we manage existing habitats for more production?

The abundance of invading bighead and silver carps is on the rise. Distribution of these fishes will almost certainly expand into upper pools in the near future. Because these fish feed on plankton, they have the potential to compete with native plankton feeders, such as paddlefish, as adults, and with almost all native species at the larval and juvenile stages when most fishes feed on plankton. Elimination of these species from the system is now virtually impossible, so managers will need to determine how to manage in their presence, including developing ways to control their numbers and their effects.