The eggs are free in freshwater lakes and rivers, where they enter the bodies of pike, turbot and other fishes, and are thus eaten by man.
The species of greatest use is the river-lamprey, which as bait is preferred to all others in the cod and turbot fisheries of the North Sea.
Shad and striped bass are both very abundant and cheap. Black bass, flounders, terrapin, sea-turtles, perch, turbot, sole and catfish are also common.
The rivers and lakes are generally well stocked with fish, such as salmon, trout of various species, gwyniad and vendace (especially in the north), pike, eels, perch of various species, turbot, bream and roach.