The Croakers: Sciænidæ.—The family of Sciænidæ (croakers, roncadors) is another of the great groups of food-fishes. The species are found on every sandy shore in warm regions and all of them are large enough to have value as food, while many have flesh of superior quality. None are brightly colored, most of the species being nearly plain silvery.
Fig. 291.—Spotted Weakfish, Cynoscion nebulosus. Virginia.
Special characters are the cavernous structure of the bones of the head, which are full of mucous tracts, the specialization (and occasional absence) of the air-bladder, and the presence of never more than two anal spines, one of these being sometimes very large. Most of the species are marine, all are carnivorous; none inhabit rocky places and none descend to depths in the sea. At the least specialized extreme of the family, the mouth is large with strong canines and the species are slender, swift, and predaceous.
The weakfish or squeteague (Cynoscion regalis) is a type of a multitude of species, large, swift, voracious, but with tender flesh, which is easily torn. The common weakfish, abundant on our Atlantic coast, suffers much at the hands of its enemy and associate, the bluefish. It is one of the best of all our food-fishes. Farther south the spotted weakfish (Cynoscion nebulosus), very incorrectly known as sea-trout, takes its place, and about New Orleans is especially and justly prized.
The California "bluefish," Cynoscion parvipinnis, is very similar to these Atlantic species, and there are many other species of Cynoscion on both coasts of tropical America, forming a large part of the best fish-supply of the various markets of the mainland. On the rocky islands, as Cuba, and about coral reefs, Sciænidæ are practically unknown. In the Gulf of California, the totuava, Cynoscion macdonaldi, reaches a weight of 172 pounds, and the stateliest of all, the great "white sea-bass" of California, Cynoscion nobilis, reaches 100 pounds. In these large species the flesh is much more firm than in the weakfish and thus bears shipment better. Cynoscion has canines in the upper jaw only and its species are all American. In the East Indies the genus Otolithes has strong canines in both jaws. Its numerous species are very similar in form, habits, and value to those of Cynoscion. The queenfish, Seriphus politus, of the California coast, is much like the others of this series, but smaller and with no canines at all. It is a very choice fish, as are also the species of Macrodon (Ancylodon) known as pescadillo del red, voracious fishes of both shores of South America.
Plagioscion squamosissimus and numerous species of Plagioscion and other genera live in the rivers of South America. A single species, the river-drum, gaspergou, river sheepshead, or thunder-pumper (Aplodinotus grunniens), is found in streams in North America. This is a large fish reaching a length of nearly three feet. It is very widely distributed, from the Great Lakes to Rio Usumacinta in Guatemala, whence it has been lately received by Dr. Evermann. This species abounds in lakes and sluggish rivers. The flesh is coarse, and in the Great Lakes it is rarely eaten, having a rank odor. In Louisiana and Texas it is, however, regarded as a good food-fish. In this species the lower pharyngeals are very large and firmly united, while, as in all other Sciænidæ, except the genus Pogonias, these bones are separated. In all members of the family the ear-bones or otoliths are largely developed, often finely sculptured. The otoliths of the river-drum are known to Wisconsin boys as "lucky-stones," each having a rude impress of the letter L. The names roncador, drum, thunder-pumper, croaker, and the like refer to the grunting noise made by most Sciænidæ in the water, a noise at least connected with the large and divided air-bladder.
Fig. 292.—Mademoiselle, Bairdiella chrysura (Linnæus). Virginia.
Numerous silvery species belong to Larimus, Corvula, Odontoscion, and especially to Bairdiella, a genus in which the second anal spine is unusually strong. The mademoiselle, Bairdiella chrysura is a pretty fish of our Atlantic coast, excellent as a pan fish. In Bairdiella ensifera of Panama the second anal spine is enormously large, much as in a robalo (Oxylabrax).