for both years are not available, but this jump in fishing success is believed 

 mostly due to a significant increase in trawler size (and power) and the cor« 

 respondingly greater number of vessels with refrigeration facilities. 



Also worthy of note is the tendency toward westward extension of 

 the fishing grounds. With the advent of larger vessels and refrigeration equip** 

 ment, increasing poundages of industrial species are being taken west of the 

 Delta, Contrasted to only 16 percent in 1959, an estimated 60 percent of the 

 total industrial-fish harvest originated here in I960. As in the past, all fish- 

 ing was concentrated inside the 20-fathom contour. 



Composition of landings As determined from catch samples, representa- 



tives of the Sciaenidae, especially the Atlantic croaker, Micropogon undulatus 

 (49%); spot, Leiostomus xanthurus (11%); and silver seatrout, Cynoscion nothus 

 (11%) continued to dominate industrial bottom-fish landings. Also reflecting 

 no change in connposition over previous years was the prevalence of Atlantic 

 cutlassfish, Trichiurus lepturus (5%); inshore lizardfish, Synodus foetens 

 (2%); scaled sardine (razorbelly), Harengula pensacolae (2%); and sea catfish, 

 Galeichthys felis (2%). 



Life history studies Supplementary sampling of bottom-fish landings for 



attributes of the dominant species, viz. , Atlantic croaker, spot, and silver 

 seatrout, was initiated in I960 for the purpose of enhancing our knowledge of 

 the biology of these important fishes. Analyses of data are incomplete, but 

 some indication of annual reproductive patterns is provided by the accompanying 

 schematic which shows, on a monthly basis, the category of development into 

 which the highest proportion of gonads for each species was classified. 



Diagram showing sea* 

 sonal progression of 

 gonad maturation in 

 three Gulf of Mexico 

 bottom fishes (1-20 

 fathoms just east and 

 west of Mississippi 

 River Delta). 



FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 



The Atlantic croaker spawns in the fall in the open waters of the 

 north central Gulf of Mexico near the mouths of passes leading into shallow 



28 



