The accumulative number of species was plotted against the number of 

 samples (Fig. 24). The percentages of the total number of species 

 occurring in the first four samples for each station were: Station 1, 

 100 percent; station 2, 88.9 percent; station 3, 70.6 percent; station 

 4, 88.9 percent; and station 5, 94.4 percent. In all cases, the 

 additional species occurring in samples 5 to 12 were represented by a 

 single individual. 



The percentage of individuals collected in the first four samples 

 at stations 2 to 5 was about 33 percent of the total. At station 1, 

 the percentage of individuals occurring in the first four samples was 

 only 15 percent. This is probably due to the low diversity of animals 

 and the clumping of the abundant animals. 



Based on the above information, four plug samples per station were 

 deemed sufficient to determine species composition and their abundance. 



4 . Results . 



Benthic plug sampling in the nearshore zone of the Gulf of Mexico 

 produced 26 major macroinvertebrate taxa and 170 species. In addition, 

 nine species of fish were also taken in the samples (Table 15). The 

 most abundant taxon in terms of species was the polychaetes with 69 

 species. Other abundant taxa in decreasing order were Amphipoda 

 (22 species); Pelecypoda (14 species); Gastropoda (12 species); and 

 Brachyura (11 species). Thirteen major taxa were represented by a 

 single species (Table 15) . 



Analysis of the benthic animals will be divided into several 

 sections. The numbers of species and individuals vary by distance 

 from shore, by season, and to a lesser extent by transect. 



The numbers of individuals of each species caught per sampling trip 

 at each station are listed by station in Appendix F. Numbers are 

 totals of four plug samples taken during each station visit. 



a. Distance From Shore . The number of species occurring at the 

 six different sites in relation to distance from shore varied 

 considerably. Station 1, located in the swash zone, had the least number 

 of species; station 5 had the highest (Table 16). Stations A and B, 

 located in 30 feet of water, had the highest average number of 

 individuals per sample. 



The benthic macroinvertebrate fauna in the nearshore zone from the 

 swash zone out to the 10-foot depth consists principally of 14 species. 

 These 14 species constitute at least 80 percent of the individuals 

 occurring at stations 1 to 5 on the nine transect lines sampled. Each 



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