Water Management to Control Clam Shrimp, 'Cyzicus morsie', in Walleye,'Stizostedion vitreum', Production Ponds

摘要

Clam shrimp, Cyzicus morsie, can occur in hatchery ponds in such dense numbersthat they interfere with the production of fish. Hatchery ponds are frequently left dry during the fall and winter and are filled in spring or early summer, simulating the vernal pools where clam shrimp naturally occur. Ponds left dry over winter and ponds that were full over winter, but were drained and dried for a period of time immediately prior to stocking, had the highest numbers of clam shrimp (P = 0.001). Clam shrimp were controlled by preventing hatchery pond substrate from drying during winter and early spring; however, the absence of drying may cause other problems that interfere with fish production.