WENNER AND WENNER: CRUSTACEANS FROM COASTAL HABITATS 



ico (Hildebrand 1954). Anderson et al. (1977) seined 

 422 specimens in the surf at Folly Beach, SC and 



A. cribrarius was the most abundant macroinver- 

 tebrate collected in the same area by DeLancey 

 (1984). In the present study, A. cribrarius consti- 

 tuted only 2% of the total catch of decapods and 

 stomatopods but occurred in 43% of the total col- 

 lections (Table 1). Mean catch per tow increased 

 from northern to southern sampling areas, with 

 highest catches (10 individuals/tow) off Florida. 

 Catches decreased to 5 individuals/tow off Georgia 

 to 2 individuals/tow off North Carolina/South Caro- 

 lina. The stratified mean catch per tow showed a 

 seasonal trend with highest catch occurring in sum- 

 mer and fall (Table 5). This corresponds with obser- 

 vations reported by Anderson et al. (1977) who 

 found a positive correlation of number of crabs with 

 water temperature. 



Average carapace width was greatest for indivi- 

 duals collected off South Carolina/North Carolina 

 (x CW = 82 mm, n = 286). Those from strata off 

 Georgia (n = 436) and Florida {n = 544) averaged 

 78 mm. Size differences were noted between sea- 

 sons, as well; however, the small number of indivi- 

 duals collected in winter (n = 13) did not provide 

 adequate information on size composition for that 

 season. During spring (x CW = 81 mm, n = 97), 

 summer (x CW = 77 mm, n = 794), and fall (i 

 CW = 83 mm, n = 362), the size composition of the 

 catch was similar. 



The M:F ratio was significant for every season ex- 

 cept winter (Table 6). Male A. cribrarius were larger 

 (S CW = 82 mm, n = 721) than females (i CW = 

 76 mm, n = 545). 



Trachypenaeus constrictus 



This penaeid shrimp is caught incidentally in the 

 commercial shrimp fishery along the southeastern 

 and Gulf coasts. Eldred (1959) reported that T. con- 

 strictus, along with T. similis, constituted 7% of the 

 annual catch in the Tortugas area of Florida. In the 

 South Atlantic Bight, T. constrictus was most abun- 

 dant in the 9-18 m depth zone sampled by Wenner 

 and Read (1981, 1982). 



This species was seasonally abundant in collections 

 from the coastal zone, with stratified mean catch 

 per tow highest in fall (6 individuals) and winter (5 

 individuals) (Table 5). Increased abundance of the 

 species during fall and winter was previously noted 

 by Wenner and Read (1981, 1982) and is probably 

 due to recruitment from spawning in spring and late 

 summer (Williams 1969; Anderson 1970; Subrah- 

 manyam 1971). The number of individuals per tow 



did not noticeably differ between the areas sampled 

 (Fig. 4). 



Libinia emarginata 



The common spider crab ranges from Nova Scotia 

 to south Florida where it occurs mostly on mud and 

 mud-sand bottom in shallow water (Powers 1977). 

 This species was reported by Hildebrand (1954) to 

 be the most common large spider crab on the west- 

 ern Gulf of Mexico shrimping grounds. Winget et 

 al. (1974) found L. emarginata seasonally most 

 abundant in spring and summer in Delaware Bay 

 where it was common in mud of sloughs. This spe- 

 cies ranked 14th in overall abundance in the current 

 study and occurred in 56% of the trawl collections 

 (Table 1). Abundance of L. emarginata was nearly 

 equal between the three areas: 4 individuals/tow off 

 Florida, 3 individuals/tow off Georgia, and 3 indivi- 

 duals/tow off North Carolina/South Carolina. The 

 stratified mean catch per tow differed among sea- 

 sons with abundance highest in winter and spring 

 (Table 6). 



Carapace length was similar between areas, with 

 largest individuals collected off Georgia (S CL = 

 54 mm, n = 232), while those from Florida and 

 North Carolina/South Carolina waters averaged 52 

 mm (n = 283) and 50 mm (n = 451), respectively. 

 Analysis of size frequencies by season (not shown) 

 indicated a broad range of sizes. Small individuals, 

 reportedly associated with the coelenterate Stomo- 

 lophus meleagris (Hildebrand 1954), occurred in low 

 numbers during every season. Average size of the 

 sampled individuals was lowest in spring (5 CL = 

 47 mm, n = 312) and summer (x CL = 50 mm, n 

 = 179), while those collected in fall (i CL = 57 

 mm, n = 193) and winter (5 CL = 54 mm, n = 

 282) were slighter larger. 



Sex ratios were significantly different from unity 

 in winter, when males dominated (Table 6). Winget 

 et al. (1974) also noted dominance by male L. 

 emarginata in winter. Carapace length differed be- 

 tween the sexes, with males slightly larger (x CL 

 = 53 mm, n = 514) than females (x CL = 50 mm, 

 n = 447). 



Penaeus duorarum 



Pink shrimp occur from southern Chesapeake 

 Bay to the Florida Keys, along the coast of the Gulf 

 of Mexico to the southern Yucatan Peninsula 

 (Williams 1984). In the southern United States, P. 

 duorarum occurs in commercial quantities only off 

 North Carolina. Pink shrimp reach maximum abun- 



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