MORTALITY IN PIKE-PERCH EGGS IN HATCHERIES
By
FRANZ SCHRADER
The remarkable losses in the hatching of pike-perch {Stizostedion.^fedion ”vitrev ) eggs have frequently made this phase of fish culture a ground for investigation. It is, however, not unjust to say that very little detailed study has been made and that no definite conclusion as to the causes of the high death rate has ever been reached.
The methods used in the handling of parent fish and eggs are. in the main, very much alike at the various stations that hatch pike perch. The fishes are caught in nets that are usually pulled once a day, weather permitting. Those that are ripe are stripped immediately, either in the field or at the hatchery, while the rest are retained in pens or live boxes.