the most part with the current, the time required to cover 

 the distance between the groins varied considerably 

 because of differences in current velocity. Our catch, 

 then, was affected both qualitatively and quantitatively 

 to unknown degrees by variations in the current. 



In the tidal pool all individuals greater than a certain 

 critical size would appear to be captured with ease. 

 However, experience showed that this was not the case. 

 Due to the configuration of the tidal pool, particularly 

 when it was in part or entirely associated with one (or 

 both) of the groins, animals were seen that were not 

 collected. 



RESULTS AND DISCUSSION 



Collections 



A total of 87 collections were made, 51 in the surf 

 (Table 1) and 36 in the tidal pool (Table 2). Each collec- 

 tion in the surf yielded at least one species of fish (1-9) 

 and all but 14 at least one swimming invertebrate species 

 (1-6). Twenty-eight of the 36 collections in the tidal pool 

 produced at least one species offish (1-7), but swimming 

 invertebrates (one species) were obtained in only eight 

 collections. The total number of species of fishes and 

 swimming invertebrates varied from 1 to 13 per collec- 

 tion in the surf and to 7 in the tidal pool. 



The number of fishes per collection in the surf varied 

 from 2 to 310; the number of swimming invertebrates 

 from to 79. In the tidal pool the number of fishes per 

 collection ranged from to 759; the number of swimming 

 invertebrates from to 12. The total number of specimens 

 of fishes and swimming invertebrates ranged from 2 to 

 311 per station in the surf and to 759 in the tidal pool. 



The weight of fishes per collection in the surf varied 

 from 7 to 2,045 g, that of swimming invertebrates from 

 to 655 g. The weight of fishes per collection in the tidal 

 pool varied from to 817 g, that of swimming in- 

 vertebrates from to 7 g. The total weight of fishes and 

 swimming invertebrates varied from 7 to 2,047 g per sta- 

 tion in the surf, and from to 817 g in the tidal pool. 



Some 512 specimens of swimming invertebrates 

 representing 4 phyla, 4 classes, 6 orders, 11 families, 

 about 15 genera, and at least 17 species; and 5,095 

 specimens of bony fishes representing 7 orders, 19 

 families, 32 genera, and 41 species were collected and ex- 

 amined during this study. About 350 specimens 

 representing at least 32 additional species of in- 

 vertebrates were also collected. This group of species in- 

 cluded nonswimming motile forms characteristic of 

 calmer offshore waters, unattached bottom -dwellers of 

 the surf zone (such as pelecypods and echinoderms), and 

 detached offshore sessile organisms. Seventeen of these 

 species (represented by 102 specimens) were collected 

 only on 16 July 1971 shortly after a tropical storm passed 

 near the coast of South Carolina. Because these 32 ad- 

 ditional species of invertebrates are not ordinarily found 

 in the surf zone or are bottom -dwellers not adequately 

 sampled by our method of collection, they are not con- 

 sidered further. 



Sixteen of the 17 species of swimming invertebrates 

 were found in the surf, but only five were found in the 

 tidal pool. Nearly all of the specimens (491 of 512) and 

 nearly all of the mass of swimming invertebrates (4,291 

 of 4,300 g) were found in the surf. 



All 41 species of fishes collected were found in the surf, 

 but only 16 appeared in the tidal pool. Approximately 

 54% of the specimens (2,747) were seined in the surf and 

 about 46% (2,348) in the tidal pool. Approximately 74% 

 (12,866 g) of the ichthyomass was caught in the surf and 

 about 26% (4,452 g) in the tidal pool. The mean weight of 

 fishes from the surf was more than twice the mean weight 

 of those from the tidal pool (4.68 to 1.90 g). Larger fishes 

 tend to avoid being trapped in shallow tidal pools as the 

 tide ebbs, whereas smaller individuals may find refuge in 

 these relatively predator-free pools. It is conceivable that 

 these transient pools provide havens that are important 

 to the survival of the fry of species such as Trachinotus 

 carolinus and Mugil curema and to individuals of most 

 size ranges of Fundulus majalis and Menidia menidia. 

 Individuals of the latter two species may seek these quiet 

 waters for feeding. Although one of the effects of fishes 

 concentrating in a tidal pool is to make them more 

 vulnerable to some piscivorous birds, the advantages of 

 temporary residence in an isolated pool (protection from 

 predatory fishes and certain birds and the availability of 

 food) may far outweigh this disadvantage. Of the most 

 important species, the fishes Anchoa mitchilli and Men- 

 ticirrhus littoralis and the decapod crustacean Arenaeus 

 cribrarius were collected almost exclusively in the surf, 

 while the fish Fundulus majalis was caught almost en- 

 tirely in the tidal pool. Table 3 presents summaries of 

 data on collections, size ranges, total weights, tempera- 

 ture, and salinity for fishes and Arenaeus cribrarius, and 

 Table 4 presents the monthly size range and number col- 

 lected per month for fishes and A. cribrarius. In both 

 tables A. cribrarius is included because it was the only 

 invertebrate species collected in sufficient numbers for 

 analysis. Data on the other swimming invertebrates col- 

 lected are presented in Table 5. 



The numbers of specimens collected were quite small 

 compared with those of some surveys. Our small catches 

 resulted from the difficulties encountered in collecting in 

 the surf and the limitations imposed by our sampling 

 procedure (the absence of replicate tows and collecting 

 sites and the use of a small beach seine). The similarities 

 in the two years in the compositions of the collections 

 and the seasonal trends indicate that our methodology 

 was adequate for giving an estimate of some of the en- 

 vironmental and population parameters of the area. 



Comparisons of Yearly and Seasonal 

 Abundance of Fishes 



Comparisons of numbers of species and specimens and 

 total weights of fishes are presented in Table 6. These are 

 discussed in this section. In the section on the Analysis of 

 Abundance of Fishes, the statistics of the data given in 

 Table 6 are examined. 



