Vertical transport dynamics of striped bass eggs

Eggs of the striped bass, Morone saxatilis (Walbaum), were obtained from the Eagle Bend Hatchery in Clinton, Tennessee. Terminal sinking velocities in static water were determined for live eggs of females from Norris and Chickamauga Reservoirs. A significant difference was indicated for egg terminal sinking velocity based on the lake origin of the female. It was not possible to determine the original strain of the females or whether hormone injections of females prior to spawning affected egg density. Terminal sinking velocity was found to be highly correlated with both egg diameter and the ratio of oil globule diameter to yolk diameter, but correlation was highest for the latter.

Terminal sinking velocities for stained eggs from Norris and Chickamauga females were also determined, and the vertical transport rates of these eggs were studied in laboratory flows. Experiments were conducted for six flow rates over smooth and rough substrates. Vertical transport rate was shown to be a function of egg density and the shear velocity of flow.

The relative number of eggs suspended under various flow conditions was determined and related to terminal egg sinking velocity and the shear velocity of flow. A method was developed by which the percentage of eggs suspended in natural stream flow may be estimated.