The cod spawns in February, and is exceedingly prolific, the roe of a single female having been known to contain upwards of eight millions of ova, and to form more than half the weight of the entire fish.
The sprat spawns in the open sea from February to May and is only occasionally captured in the ripe condition.
In the Elbe the twaite shad spawns below Hamburg, the allis shad above Dresden.
It spawns at a distance from the shore, and its eggs are buoyant, like those of many other marine fishes and unlike those of the herring, which are adhesive and demersal, i.e.
It feeds on small freshwater animals and soft vegetable matter, and spawns in April or May.