production east of the Delta occurred during September-December when suc- 

 cessful trawling west of the Delta was precluded due to bad bottom and accum- 

 ulations of debris resulting from Hurricane Carla. 



A standard unit of effort was established to furnish a reasonable in- 

 dex of fish abundance and measure of fishing success on the grounds. Prelim- 

 inary analysis of 1961 data shows that the average catch per 1 -hour tow using 

 a standard 65-foot, balloon-type otter trawl was 0. 62 tons west of the Delta 

 and 0.51 tons east of the Delta 



Five species accounted for approximately 81 percent of the 1961 

 industrial bottomfish catch. Atlantic croaker, Micropogon undulatus, again 

 topped all species by a wide margin. Comparative data for the period 1959-61 

 are shown in the accompanying graph. The year-to-year stability of catch 



25 r 



<n 20 



z 

 o 



z 



4 

 CO 



15 - 



10 



5 - 



Connparative landings of 

 dominant bottomfish species 

 taken by industrial -fish 

 fishery off north central 

 Gulf coast, 1959-61. 



1959 



I960 



1961 



composition (in terms of the major contributing species) is particularly note- 

 worthy. 



Life History Studies An intensive sampling project at the Galveston Labora- 



tory's Field Station in Pascagoula, Miss. , is furnishing basic information on 

 the life history and general biology of Atlantic croaker; spot, Leiostomus 

 xanthurus; sand seatrout, Cynoscion arenarius; and silver seatrout, C. nothus. 

 A major portion of this project involves the study of variation in relative 

 strengths of successive age groups ("year classes") of each species. Because 

 attempts to validate the scale nnethod of age determination are not yet com- 

 plete, analysis of length distributions of the samples, despite its acknowledged 

 subjectivity, has had to be relied upon for age assessment. Findings reported 

 in the following discussion, which is restricted to the Atlantic croaker, must 

 therefore be viewed as preliminary. 



On a semiweekly schedule over the period July 1961 to May 1962, 

 7, 500 croakers were examined for total length, weight, sex, and maturity 

 from commercial catches nnade east of the Mississippi Delta (2-20 fm. ) and 

 landed at Pascagoula. Subsampling provided the scale samples being examined 

 to decide on the feasibility of their use in determining age. After being com- 

 piled in 5-mm. classes and connbined according to month of sampling, the 

 plotted length measurements are shown in the accompanying figure. 



40 



