Paddlefish (Polyodon spathula): Growth and Food of Young of the Year and a Suggested Technique for Measuring Length

Abstract

The mean total length of young-of-the-year paddlefish (Polyodon spathula) from Lewis and Clark Lake (a main-stem Missouri River reservoir at the Nebraska-South Dakota border) was 215 mm on 31 August of the first summer of life and estimated to be 296 mm by the end of the first growing season; average growth rate was 2.7 mm/day. The diet in 1972 consisted of zooplankton and aquatic and terrestrial insects. Daphnia pulex was by far the most important food occurring in stomachs of all 79 fish 30-149 mm long. Aquatic insects were important in late June and early July, and in August. The kinds of insects found in the stomachs suggested that the young fish fed at night in open water, near the surface.