WENNER AND WENNER: CRUSTACEANS FROM COASTAL HABITATS 



FIDELITY 



SIMILARITY 



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SITE GROUPS 



Figure 3.— Confma^rf— coincidence from pooling collections dur- 

 ing a season within each stratum. 



Ovalipes stephensoni 



This portunid crab, which was the third most 

 abundant species collected in this study (12% of total 

 catch), occurs off Virginia (Musick and McEachran 

 1972) to near Biscayne Bay, FL (Park 1969). Adult 

 0. stephensoni are found farther from shore than 

 adults of its congener 0. ocellatus; however, young 

 of both species occur nearshore (Williams 1984). 

 Wenner and Read (1982) found 0. stephensoni to 

 reach maximum abundance from 9 to 18 m between 

 Cape Fear, NC and Cape Canaveral, FL. In the 

 study area, 0. stephensoni was most numerous in 

 strata off South Carolina and North Carolina where 

 43 individuals/tow were collected. Catches decreased 

 off Georgia to 29 individuals/tow and were lowest 



in strata off Florida (<1 individual/tow). Stratified 

 mean catch per tow was highest in spring (120 in- 

 dividuals/tow) and declined markedly during other 

 seasons (Table 5, Fig. 4). 



Analysis of size composition indicated mean cara- 

 pace width differed between strata and season. 

 Largest crabs were found off Florida (x CW = 45 

 mm, n = 63), while average sizes off Georgia (n = 

 713) and South CarolinaTNorth Carolina {n = 2,349) 

 were 30 mm and 34 mm, respectively. Ovalipes 

 stephensoni collected in fall were larger (x CW = 

 42 mm, n = 273) than those collected during other 

 seasons (winter: x CW = 38 mm, n = 199; spring: 

 z CW = 30 mm, n = 1,591; summer: S CW = 36 

 mm, n = 1,062). 



Analysis of sex ratios by season indicated signif- 



165 



