160 BULLETIN OF THJE BUREAU OF FISHERIES 



At 6 millimeters the black drum has the vertical fins better developed, with 

 6 anal rays being discernible usually. This anal-ray count seems most constant and 

 accordingly separates the species from other related ones. The dorsal and ventral 

 fin folds stUl persist, although now separate from the tail, while the yolk sac is reduced 

 further. The two ventral chromatophores are well marked and weak spines are 

 present on the opercle or gill cover. (See fig. 14.) 



A marked change occurs in the general pigment arrangement when the fish has 

 reached a length of about 8 millimeters. Black chromatophores appear in profusion 

 dorsally as well as along the sides and tend to arrange themselves into definite groups 

 extending from the nape to the caudal peduncle. These groups are the forerunners of 

 the six vertical black bars that soon appear, to remain until adult size is reached. 

 On fish of about 8 millimeters, however, all six bars are rarely discernible in one speci- 

 men. All vertical fin rays are well formed and easily counted — dorsal, X-I, 21-23; 

 anal, II 6. The ventral chromatophores present in the smaller stages tend to 

 disappear entirely. (See fig. 15.) 



When a size of 15 millimeters is attained, the young drum has assumed the 

 general adult shape. The six black bars are pronounced and extend vertically from 

 the back to slightly below the lateral line. All fins, with the exception of the dorsal, 

 are colorless. The dorsal is dotted heavily with black punctulations, particularly 

 along the anterior spines, while the soft rays are marked less heavily. The color of 

 the body above the lateral line is light brown, marked with black vertical bars, while 

 below the lateral line a bright silvery sheen prevails. The series of mandibulary 

 barbels are now evident. (See fig. 16.) 



In drum above 25 millimeters the color pattern remains essentially the same, 

 with the exception that the pectorals and anal assume a black cast and the fish tends 

 to become darker with age. (See figs. 17 and 18.) 



SPAWNING AND EARLY DISTRIBUTION OF YOUNG 



Along the coast of Texas the black drum spawns principally from February 

 to May in the Gidf of Mexico near the mouths of the passes leading into the bays 

 and lagoons. A late or secondary spawning period may also occur from late July to 

 November. Both spawning seasons are preceded by well-defined migrations of the 

 adult fish to the spawning grounds of the Gulf. The newly hatched drum are 

 brought into the bays by the tidal current and soon distribute themselves into more 

 or less definite localities. 



The presence of large numbers of ripening adult drum within many of the more 

 shallow bays and lagoons has led to the opinion among many that the species spa^vns 

 within these bays and lagoons. The drum, well recognized as preferring the shallow 

 and muddy areas of Nueces and Oso Bays and parts of Laguna Madre, is found in 

 the greatest abundance within these particular bodies of water, and the casual 

 observer might easily be led to believe that the entire life of the fish was spent within 

 such localities. It was found, however, during the course of the recent study, that 

 the spawning habits of the black drum were complicated, and that the general sup- 

 position of a bay spawning habitat was not tenable in the light of the results obtained 

 by the writer during 1926 and 1927. 



