PROGRESS IN BIOLOGICAL INQUIRIES, 192 7 213 



Jriim, and spotted trout spawn within the bays or in the Gulf of 

 Mexico itself has been given attention. All the evidence indicates 

 that the redfish and black drum spawn in the Gulf, but that the 

 spotted trout spawns in the shallow, grassy lagoons and bays that 

 line the coast. 



Soon after hatching, the young of the redfish. drum, croaker, and 

 spot swarm voluntarily or are carried by the currents through the 

 passes into the bays, where they spend their early life. At times the 

 concentration of larval and postlarval fishes around the passes is re- 

 markable, thousands often being obtainable in a few square feet of 

 water area. 



Detailed studies of growth, based on length- frequency and scale 

 analyses, have yielded interesting results in the case of several fishes. 

 The redfish {Scimiops ocellatus)^ spawned in late September or early 

 October, reaches a modal length of about 34 centimeters by the end 

 of its first year of life and about 55 centimeters by the end of the sec- 

 ond year. Fish at these ages and sizes are excellent for market; 

 the l-year-olcl fish weigh about I14 pounds and the 2-year-olds about 

 4 pounds. The black drum, while not showing the same rate of 

 growth as the redfish, nevertheless reaches marketable size by the end 

 of its first year. The annual growth of this species for the first six 

 years and of the spotted trout for the first nine years has been de- 

 termined also. 



A systematic study of the entire fish fauna of the Texas coast was 

 undertaken early in the year by Isaac Ginsburg. This study is based 

 largely on collections made incidental to the study of the life histories 

 of the commercially important species and the collections made by the 

 Gravipus in the coastal waters in the Gulf in 1916. These latter, 

 while not extensive enough for a complete study, so far have yielded 

 interesting information. Identification has shown that they comprise 

 about 135 distinct species, a few apparently new. This is probably 

 only about two-thirds of the entire number of species actually exist- 

 ing on the coast of Texas. Tentatively it may be stated that the fish 

 fauna of the Texas coast is similar to that of the coast of the Caro- 

 linas. The majority of species are the same, and the dominant species 

 in each region are the red drum, black drum, mullet, croaker, spot, 

 spotted weakfish, and pigfish. 



The fish fauna of the Gulf coast is very interesting from a distribu- 

 tional standpoint. Nearly all of the species that give character to the 

 fauna in both regions (with the notable exception of the cosmopolitan 

 mullet) do not occur in southern Florida. So far as migration from 

 the one region to the other is concerned, the subtropical waters of 

 southern Florida serve as an effective barrier. 



The sand trout, which is very common on the Gulf coast and is 

 marketed to some extent, but is not common on the Atlantic coast, 

 has received special study, which has shown that there are two dis- 

 tinct forms that differ decidedly in the number of rays in the dorsal 

 and anal fins. These two forms have been designated tentatively as 

 Cynoscion nothu^ and Cynoscion thalassinus Holbrook. The com- 

 mon form on the Texas coast is not C. nothus, but the other species. 



16147—28 3 



