The Soupfin Shark, Galeorhinus zyopterus, from the coast of California and Baja California, has long been well known to the Chinese, who consider its fins superior to almost all others as an essential ingredient of certain soups. The fins are cut off and thoroughly dried, in which condition they can be shipped. Before they are used, they are soaked in warm water, and the cartilaginous rays, that in life gave the fin its strength, are separated from the flesh. Then these rays are sliced up and boiled with meat, chicken, vegetables, and so forth, to make soup.
Not until 1937 did the soupfin shark become generally known. At that time an intensive fishery for this species was instituted to obtain its liver, which had been found to be extraordinarily rich in vitamin A. Since soupfin livers sold for as much as thirteen dollars a pound, and an average female’s liver might weigh as much as fifteen pounds, small fortunes were made on a few boatloads of these sharks. Within three years, however, the number of sharks taken fell off to such an extent that many fishermen had to abandon the fishery. It is believed most probable that this reduction in numbers may have resulted from over-fishing, because the soupfin shark is apparently a slow reproducing and maturing species.
Male soupfin sharks mature at a length of about five feet, the females at a somewhat larger size. The young are born alive, and an average brood consists of thirty-five individuals.