STONKR: SKACKAS.S l( HTH YOKACXA 



because of the heavy winter passage of juvenile spot 

 and pinfish. 



The number of fish species collected in Apalachee 

 Bay was highest in July and August, concurrent with 

 peaks in total abundance (Fig. 1). Total number of 

 species, however, ranged only from 32 at station E- 12 

 to 36 at F- 1 2 , and there was no significant relationship 

 between macrophyte biomass and species richness 

 on either a spatial or seasonal basis. 



Analysis of length- frequency data for pinfish, using 

 ontogenetic stages discussed in earlier studies of the 

 species (Stoner 1980b; Stoner and Livingston 1984) 

 revealed differences in size-frequency distribution 

 among the populations found at the four stations in 

 Apalachee Bay (Table 4). At the unvegetated site, the 

 pinfish population was dominated by fish in the 11- 

 15 mm class (51.6$ of the total) which appeared 

 primarily in February and March. Among the 

 vegetated sites, however, the number of small 

 juveniles (16-35 mm) increased with seagrass 

 biomass, as did the number of large juveniles (36-80 

 mm). The number of pinfish >80 mm decreased with 

 seagrass biomass at the vegetated sites, but were also 

 relatively uncommon at the unvegetated site. 



Table 4. — Distribution of Lagodon rhomboides at four seagrass 

 sites in Apalachee Bay, Fla., based on size class. SL is standard 

 length of fish; .V is the total number of fish collected in a size 

 class. 



Role of Seagrass Species 



A total of 2,580 fishes representing 37 species were 

 collected during daytime sampling at three stations 

 in Indian River lagoon (Table 5). Unlike collections 

 made in Apalachee Bay, spatial variation in the abun- 



dance of fishes was not related to seagrass biomass 

 (Tables 6, 7); rather, fish abundance varied widely 

 with seagrass species, independent of macrophyte 

 biomass. The lowest number of individuals was 

 found in beds of Syringodium filiforme (Table 5) . Two 

 and one-half times more fish were collected in 

 Halodule wrightii where seagrass biomass was always 

 lowest (Table 6), and an intermediate number of 

 fishes were collected in Thalassia testudinum where 

 highest macrophyte abundance occurred consistent- 

 ly. Analyzed by individual collection date, the 

 Hcdodide bed supported greater total numbers of 

 fishes than did the other two seagrass beds, except in 

 October when equal numbers were collected in 

 Halodule and Thalassia (Table 8). Thalassia and 

 Syringodium beds supported statistically similar 

 numbers of fishes except in October. As in Apalachee 

 Bay, Lagodon rhomboides was the numerically domi- 

 nant species in seagrass meadows of Indian River 

 lagoon (Table 5). Except in October, the Halodule 

 bed supported a significantly greater number of pin- 

 fish than the other two beds (Table 8). The 

 Syringodium bed consistently yielded fewest pinfish, 

 but mean values per trawl were similar to those from 

 the Thalassia bed in January and July. 



Table 5. — Abundance of the 10 most numerous fishes at three 

 seagrass beds in Indian River lagoon, Fla. Values are the total num- 

 ber of fish collected and percentages (in parentheses) of the total 

 catch for each bed type. Mean macrophyte biomass (g dry wt/m : ) for 

 each bed type is shown in parentheses. 



Syringo- 

 dium 



Thalassia 



Halodule 



Table 6. — Aboveground biomass and blade density of macrophytes at three 

 seagrass beds in Indian River lagoon, Fla. Values are mean ± SD (n = 



8). 



841 



