Sturgeon  (Acipenser ).—These large, sluggish fishes, some reach a length of over ten feet, and live on worms, crustacea, and mollusks. The body is long and narrow with five rows of bony shields. There are many species of sturgeon, all confined to the northern hemisphere. They live in the sea and great lakes, and ascend the great rivers. All supply valuable commodities, for which they are regularly captured on a large scale. These commodities are their flesh, which is palatable and wholesome, their roe (caviare), and their air-bladders, from which isinglass is made.

The most important sturgeon-fishery in Europe is that of the Volga and the Caspian Sea. The flesh of the fish is salted, and caviare and isinglass made on a large scale from the roes and air-bladder.

The Sterlet  (A. ruthenus ) is a much smaller species, which is common in the Black and Caspian Seas, and ascends the Danube as far as Vienna. It is one of the principal objects of the sturgeon fishery on the Volga.

In America sturgeon flesh is eaten fresh, and caviare is made both in Georgia and in San Francisco; but there is no great fishery in any particular district, and the manufacture of isinglass does not receive much attention. The sturgeon of the great lakes (A. rubicundus ) and the Shovel-nose of the Mississippi valley are the chief American species.