sample. The percentage (_74.4 percent) of individuals of the 14 mqst 

 abundant species in the top 11.5-centimeter part qf the sample was 

 similar to the percentage (75 percent) of individuals' of all 179 species 

 in the top part. Four of the 14 species had ujore individuals in the 

 bottom 11.5-centimeter part than the top part of the sample. Species 

 found most abundantly in the top 11.5-centimeter part of the sample 

 were D. texasianus , S. pettiboneae, Manoocuma sp., and E. taVpoida 

 (Table 27). 



c. Biomass . The number of individuals per square meter of the 

 bottom was calculated from the number of individuals in the four plugs 

 taken at each station. Biomass for each station and date is listed in 

 Appendixes G, H, and I. 



(1) Stations . The average number of individuals per square 

 meter varied from 2,180 at station 3 to 4,636 per square meter at 

 station B. The average number of individuals from all stations was 2,744. 

 The range fluctuated from a low of 48 individuals on transect 9, station 



1 in December to a high of 35,504 individuals on transect 9, station 2, 

 in May (Fig. 29). The high value of 35,504 individuals per square meter 

 was attributable to large numbers of small D. texasianus occurring at 

 this station. The range of values after station 2 decreased with distance 

 from shore (Fig. 29). 



(2) Transects . The average number of individuals per square meter 

 varied from 1,547 on transect 3 to 3,503 individuals on transect 9. 

 Transect 3 lacked the large number of individuals that occurred on the 

 other transects in May or June, resulting in the smallest range of values 

 of the nine transects (Fig. 30). 



(3) Monthly . The number of individuals per square meter 

 fluctuated seasonally, with the months of May and June having the highest 

 abundance of individuals at station 1 (Table 28) . The species composition 

 at station 1 in May was dominated by two species; S. squamata comprised 



57.3 percent of the individuals, and D. texasianus comprised 38.3 percent 

 of the individuals. In June, the percentage of S. squamata increased to 



64.4 percent of the individuals and D. texasianus decreased to 31.2 percent 

 (Table 18). 



The numbers of individuals per square meter at the offshore transect 

 stations were highest in May for stations 2, 3, and 4, and in August for 

 station 5 (Table 28). 



e. Species Diversity . The Shannon Index of general diversity (H) 

 was calculated for the number of species and individuals in the four plugs 

 taken at each station. Diversity indexes for each station and date are 

 listed in Appendixes G, H, and 1. 



(1) Stations . The average diversity indexes at the five 



90 



