The Common Sturgeon, Acipenser sturio (Fig. 356), abounds in the North Sea and the Mediterranean, and occasionally it appears in the Thames, the Rhine, the Seine, the Loire, and the Gironde. It is usually about two yards to seven feet long, but has been known to attain the length of ten or twelve feet. Its general colour is yellow, with a white belly. It is rendered remarkable by the number and form of the osseous plates or scales, which cover the body like so many bucklers. Upon the back and belly are no less than twelve to fifteen of these rough bony plates, relieved by projections, which are pointed in the young, and soften down with age. On each side is a row of thirty to thirty-five of these triangular plates, separated from each other by considerable intervals. The head is broad at the base, gradually contracting towards the point, and terminating in a conical muzzle. The mouth is large and considerably behind the extremity of the muzzle, and its jaws, in place of teeth, are furnished with cartilages. Between the mouth and the muzzle are four slender and very elastic barbs, or wattles, like so many little worms. It is pretended that these wattles attract small fishes to the jaws of the animal, while it conceals itself among the roots of aquatic plants.
In the sea the sturgeon feeds on herrings, mackerel, cod-fish, and other fishes of moderate size. In the rivers it attacks the salmon which ascend them about the same time. Mingling with them, however, it seems a giant. It deposits its eggs in great quantity, which are gathered and made into caviare. Its flesh is delicate, and in countries where they are caught in quantities it is dried and preserved. The rivers which enter the Black and Caspian seas contain, besides the common sturgeon, many other species of the same genus, the flesh of which is even more delicate and recherché than the common sturgeon. Among the ancients this fish was held in unusual esteem. In Rome, in the time of the emperors, we read of sturgeons borne in triumph to the sound of instruments, and laid upon tables fastidiously covered and decorated with flowers.
The Great Sturgeon, which sometimes exceeds a thousand pounds, is only found in the rivers which flow into the Caspian and Black seas. The Volga, the Don, and the Danube produce the largest species.
We are indebted to the Russian naturalist Pallas for the information we possess respecting the mode of taking the sturgeon in the Volga and other Asiatic rivers. Stakes are placed across the river, leaving just sufficient space between each pile to permit the animal to pass. Towards the centre this dike forms an angle opposed to the current, and, consequently, opposed to the fish which ascend the river towards the summit of this angle. At this point there is an opening which leads into a kind of enclosure, consisting of fillets towards the end of winter, and of osier-hurdles during summer. The fishermen establish themselves upon a sort of scaffold placed over the opening. When the fish is engaged in the reservoir, the men upon the scaffold drop a gate, which prevents his return to the sea. The movable bottom of the chamber is now raised, and the fishes easily taken, as represented in Pl. XXVI.
The fishermen are informed during the day of the approach of the sturgeons to the great enclosure by the movement they communicate to cords suspended to small floating substances in the water. During the night the sturgeons enter the enclosure, agitating by their movements other cords arranged round the hurdles. The agitation communicated to the cord is sufficient to shut the gates behind; they are thus imprisoned by the dropping of the gate, which in falling sounds a bell to wake the watching fisherman on the scaffold, should he be asleep. The sturgeon-fisheries of the Volga are thus admirably organized. Gmelin describes with some minuteness the sturgeon-fishing, during the winter, in the caverns and hollows of the river-banks near Astrakhan, in the estuary of the Volga. A great number of fishermen are assembled there with their boats. The flotilla approaches the retreats to which the fishes have betaken themselves, the nets are skilfully arranged all round them, and all at once the whole mass of fishermen join in a great cry, at which the frightened fishes rush from their concealment and throw themselves into the nets spread for them.
The size of the fish, the nourishing properties of its flesh, its healthy and agreeable taste, and the immense quantity of eggs produced, have a wonderful power in exciting the commerce and industry of the inhabitants of these countries. In order to give some idea of the abundance of the eggs of the sturgeon, it is stated that the weight of two ovaries equalled nearly a third of the weight of the whole animal; in other words, these ovaries weighed nearly eight hundred pounds in a female whose weight was two thousand eight hundred pounds.
It is with these eggs chiefly, but not altogether, that caviare is prepared; and the article is more or less relished according to the state of the eggs. The display of caviare, as exhibited at the Universal Exposition of Paris during the year 1867, will remain to those who have visited it one of the most lasting recollections.
Plate XXVI.—Sturgeon Fishing on the Volga.