Evaluation of the Zooplankton Community of Livingston Reservoir, Texas, as Related to Paddlefish Food Resources.

摘要

Paddlefish, Polyodon spathula, are large freshwater fish that once were numerous throughout the Mississippi River and Gulf Slope drainages of the United States, but they have experienced a decline in the twentieth century. After paddlefish were declared endangered in Texas in 1977, a restoration program was begun that included stocking young fish in and upstream from Livingston Reservoir, Texas. The zooplankton community of Livingston Reservoir was examined in terms of composition, abundance, distribution, and organisms appropriate as food resources for paddlefish. By comparing the range of interraker distances of Paddlefish (0.06-0.08 mm) to size measurements of different zooplankton taxa, it was determined that paddlefish do not utilize small rotifers and copepod nauplii as efficiently as they do larger copepods and cladocerans. Overall zooplankton abundances were greater than those reported for other Texas reservoirs, but the community was dominated in terms of abundance and biomass by small rotifers and copepod nauplii. All taxa (rotifers, cladocerans, and copepods) were comprised of relatively small organisms.