Table of Contents
The croakers have both the spiny portion and the soft portions of the dorsal fin well developed (either separate or as one continuous fin), and their ventrals are what is known as thoracic in position, i. e., about under the pectorals. They are readily separable from the sea basses (p. 389), the porgies (p. 411), and the cunner tribe (p. 473) by the fact that their anal fin has only 1 or 2 spines instead of 3, and is much shorter than the soft portion of the dorsal; from the rockfishes and sculpins by their relatively smooth head; and from all the mackerels and the pompano tribe by their stout caudal peduncles and rounded or only slightly concave caudal fins. Most of them produce loud drumming sounds by rapid contractions of certain abdominal muscles against the gas-filled air bladder; hence the common names "croaker" and "drum." The kingfish (p. 423) is an exception to this rule.
|KEY TO GULF OF MAINE CROAKERS AND WEAKFISHES|
|1.||There is no barbel on the chin||2|
|The chin bears one or more barbels||3|
|2.||Body only about one-fourth as deep as it is long (to base of caudal fin); anterior profile of head sloping only moderately; snout pointed; no dark spot behind upper corner of gill opening||—||Weakfish, p. 417|
|Body at least one-third as deep as it is long to base of caudal fin; anterior profile of head sloping steeply; snout blunt; there is a dark spot close behind the upper corner of the gill opening||—||Spot, p. 423|
|3.||Several barbels on chin; snout ends about even with front of lower jaw; cheek smooth||—||Black drum, p. 425|
|Only one barbel on chin; snout projects considerably beyond lower jaw; cheek with 2 short, tooth-like serrations||—||Kingfish, p. 423|
 Jordan (Stanford Univ. Publ., Univ. Series, Biol. Sci., vol. 3, No. 2, 1923, p. 202) placed the weakfish in his new family Otolithidae, which he separated from the Sciaenidae as having a different arrangement of vertebrae. But we think it preferable (following Smith, Sea Fishes Southern Africa, 1949, p. 223) to use Sciaenidae in the older and more inclusive sense, because the only family character marking Otolithidae off from it is internal, hence requires dissection for its recognition.