The effects of sampling gear on the survival of striped bass ichthyoplankton

Hatchery spawned and reared eggs, yolk-sac larvae and larvae from Hudson River striped bass (Morone saxatilis) were released into ichthyoplankton nets in an experimental flume at velocities of 0.5, 1.5 and 3.0 fps. Percent survival was determined immediately after exposure and, for 14-day-old larvae, after 72 hr. to assess latent mortality effects. Immediate and latent mortality was found to be velocity-dependent. Yolk-sac larvae were most sensitive to velocity during net capture, followed by post-yolk-sac larvae and eggs, in decreasing order of sensitivity. Attempts to determine survival of striped bass ichthyoplankton using net-captured organisms at steam electric stations may be affected profoundly by differences in water velocity at intakes and discharges.