In the Delaware River, where the •chief sturgeon fisheries exist, it was not valued ,pre vious to the last 60 years, but when captured was thrown away or an entire fish of several hundred pounds sold for 25 cents as hog food. The importance of the fisheries dates from about 1870, hut they have been prosecuted so recklessly that they have been already nearly depleted. Drift gill-nets are the chief means of capture. They are set on the flood tide and when the bobbing of the floats indicates the enmeshment of a fish, are drawn and the cap tive, which docile, removed. The flesh is sold fresh or smoked and is valued chiefly by the foreign population of the large cities. It brings a high average price in the market. The roes fetch a higher price and are immediately removed and worked through a wire sieve to separate the eggs, which are then placed in a brine of salt and boracic acid or similar preservative. After a sufficient treat ment they are thoroughly drained and packed in oaken kegs or cans. This product is the cele brated caviar of the Russians. Vinegar seems to be no longer employed in the preparation of caviar in America. Besides using the flesh and roes for food the swim-bladders of the stur geon are largely employed in Europe in the manufacture of isinglass. This substance is prepared by washing the sound in fresh water, and then carefully dried. The outer coat is then peeled off, the inner coat being cut into lengths or staples, which afford the isinglass. The stur geon was celebrated among the ancient, for we find that in the palmy days of the Roman Em pire sturgeons, profusely decorated with flow ers, were borne in triumph to table. In the Volga, sturgeons are captured by driving piles at close distances so as to form a barrier across the river; by this barrier the fishes are forced into an enclosure, in which they are trapped and readily seized. Formerly any sturgeon cap tured in the Thames above London Bridge might be claimed by the lord-mayor, while one caught elsewhere might be claimed by the king as a IroyaP fish. This custom doubtless arose from the high esteem in which the flesh was held by former sovereigns. Henry I is said, indeed, to have prohibited its use at any but his own table.
The white, Oregon or Sacramento sturgeon (A. transmontanus), is a still larger species, teaching a length of 13 feet and a weight of 1,000 pounds, found on the Pacific Coast. It is captured in considerable numbers in pound-nets and on set-lines in the Columbia and Sacra mento rivers. It furnishes caviar, and smoked or frozen flesh, which is shipped East. This species is said to feed chiefly on minnows. The lake.sturgeon (A. rubicundus) lives in the up per Mississippi Valley, in the Great Lakes and other smaller lakes of the central United States and Canada. It seldom exceeds 50 pounds in
weight, but is the object of important fisheries in Lakes Erie, Ontario and Lake of the Woods. It feeds on snails, crayfish and insects. The green sturgeon (A. medirostris) of the Pacific is of little value as food, though not poisonous as often stated, while the Atlantic short-nosed sturgeon (A. brevirostrum) is disregarded on account of its small size. Scophirhynchops has a broad flat snout, no spiracles, and a complete covering of bony plates on the base of the tail. Besides several Asiatic species, the white or shovel-nosed sturgeon (S. plotyrkynchas) is common throughout the Mississippi Valley and beyond, and although seldom exceeding two feet in length is much valued for' food.
The family Polyodontidce or paddle-fishes are sturgeon-like fishes sometimes placed in a separate order and distinguished from the true sturgeons especially by their remarkably pro longed spatulate snouts, the absence of maxil lary bones and the smooth unarmored skins. Psephurus gladius is found in the rivers of China, Polyodon spathula in the rivers of the Mississippi Valley. This remarkable fish stirs up the mud of the bottom with its long paddle and strains out the small organisms so exposed by means of its filter-like gill-rakers, and swal lows them. It breeds in the ponds and bayous connected with the upper parts of the rivers or in the shallows of lakes. It is captured in seines and on set-lines and the product of the fisheries is utilized in the same manner as other sturgeons. The important centres of this fish ery are along the lower Mississippi and in Lake Pepin, Minn.
The sturgeon fisheries of all parts of the country are in serious danger of being de stroyed, but the above data indicate that the evils of overfishing, etc., have been most harm ful in the Delaware River. Several attempts to propagate the sturgeon artificially have been made by the Fish Commission, but the peculiar difficulties resulting from the methods of the fisheries and the mode of reproduction of this fish have up to the present proved insurmount able.
Jordan and Evermann, 'Fishes of North and Middle America' (Vol. I Washington 1896) ; Ryder, 'Sturgeons and Sturgeon Industries of the Eastern United States' (Washington 1896) ; Cobb, 'Sturgeon Fishery of the Delaware River,' Reports of the United States Fish Commission (Washington, annually); Langworthy, 'Fish as Food' (Farm ers' Bulletin 85, United States Department of Agriculture, Washington 1905) Lankester, 'Treatise on Zoology' (London 1909); Jordan, 'Fishes) (New York 1907) ; 'Cambridge Nat ural History' (Vol. VII, London 1904) ; Goode, 'American Fishes' (New York 1888); Gunther, 'Introduction to the Study of Fishes) (Edinburgh 1880).