At the laboratory, the samples were rinsed in freshwater, sorted 

 into major animal taxa, placed into isopropyl alcohol, identified to 

 the lowest taxonomic level practicable, and then enumerated. 



The diversity index used in this report- is the Shannon index of 

 general diversity (H) : 



H- -Hf-) log (f-) 



where ni is the number of individuals of a given species and N the 

 total number of individuals (Odum, 1971). 



A special study was conducted to determine if the sampling depth of 

 of 23 centimeters was sufficient for the capture of the animals that 

 lived in this nearshore zone. 



A comparison was made between the plug sampler and a core sampler. 

 The depth of penetration by the core sampler was 46 centimeters or 

 twice the depth of the plug sampler. The diameter of the core was 

 6.35 centimeters. This sampler was modified from the one used by 

 Taylor (1965) by removing the flange. The surface area sampled with 

 the plug sampler was five times that of the core sampler. 



Samples were taken in the swash zone of Panama City Beach, Florida. 

 Forty cores were taken and each extracted core was divided into two 

 23- centimeter lengths. The contents were sieved, and the animals were 

 preserved, identified, and enumerated. 



The 40 cores produced a total of 38 benthic invertebrate individuals 

 representing seven species. Only 1 of the 38 individuals was found in 

 the bottom 23-centimeter part of the core sample. The eight plug samples 

 produced 61 benthic invertebrate individuals representing eight species. 

 Thus, it is believed that the plug sampler is more efficient in 

 sampling the benthos. Also, the time and effort expended in sampling 

 and analyzing the 40 cores are about five times greater than when eight 

 plugs are used. 



3. Adequacy of Sampling . 



A special sampling experiment was conducted to determine the number 

 of plug samples necessary to obtain a list of representative benthic 

 species occurring in the sampling area. One transect was chosen for 

 sampling and 12 plug samples were taken at each station on the transect. 

 They were numbered consecutively in the order of collection. 



The total number of species per station increased seaward from 

 station 1. Station 1 had 5 species of animals; station 2,9 species; 

 station 3, 17 species; station 4, 18 species; and station 5, 18 species. 



54 



