South Carolina 



Georgia 



Size distribution .--! have adequate size 

 distribution data for the sea bob only for 

 November in South Carolina's shallow coastal 

 shrimp fishery. In this month the mode was 

 88 nnnn. for nnales and 88 and 98 mm. for 

 females (fig. 14) -- similar to that found for 

 the Georgia grounds in November. 



53 63 73 83 93 103 113 123 133 

 48 I 58 I 6 8 I 78 I 88 I 98 I 108 | 118 | 128 | 138 





16 

 15 

 14 

 13 

 12 

 11 

 10 



9 



8 



7 



6 



5 



4 



3 



2 



1 







48 



"T 



T" 



. ' I ■ I ■ I ' 



NOVEMBER 



97 MALES =48.5% 



103FEMALES=51.5%_ 



1 r 

 58 ' 68 



> I I I I ' ■ 



78 ' 88 ' 98 ' 108 ' 118 ' 128 ' 138 

 53 63 73 83 93 103 113 123 133 



TOTAL LENGTH (MM.) 



Figure 14. — Size distribution and sex ratio of sea bobs 

 on South Carolina outside fishing grounds, November 

 1934. 



Ovary development .- -Of 1 5 females captured 

 in South Carolina in June, 20 percent were 

 developing, 26.6 percent yellow, 13.4 percent 

 ripe without attached spernnatophores, and 40 

 percent ripe with attached spermatophores 

 (table 11). In November all females had un- 

 developed ovaries except for one with de- 

 veloping ovaries. 



These limited data suggest that the spawning 

 time in South Carolina is similar to that in 

 Georgia. 



TRACHYPENEUS CONSTRICTUS 



Trachypeneus constrictus is a small penaeid 

 shrimp taken very frequently on the shallow 

 coastal shrimp fishing grounds of the south 

 Atlantic coast. Williams (1965) gave the known 

 range as, "Tangier Sound, Chesapeake Bay, 

 to Texas; Bermuda; Puerto Rico and Sombrero 

 Island; Surinam." He gave habitat as, "Pri- 

 marily sand or mud and shell bottom in high- 

 salinity waters; shallow water to 30 fathoms." 



I have limited size distribution data for the 

 shallow coastal fishing grounds for November 

 and December 1931; March, April, May, and 

 June 1932; and January 1933. All samples ex- 

 cept for June and December were fronn inside 

 grounds. Ovary development data are available 

 for all the listed months except December. 

 Comparisons of sex ratios, sizes, ovary de- 

 velopment, and spawning are made withlimited 

 data from South Carolina, and published data 

 for northeast Florida. 



The size distribution and sex ratios (fig. 15) 

 have two obvious features -- an unbalanced 

 sex ratio and a great disparity in sizes of 

 males and females. Of the 384 specimens from 

 Georgia only 31 or about 8 percent were 

 males, and in the various months the ratio 

 varied between and 22 percent. Joyce (1965), 

 reporting on a survey of the shallow coastal 

 shrimping grounds of northeast Florida, said 

 of this species, "Only 14.4 percent of the total 

 offshore T. constrictus catch were males." In 

 my sample of 37 specimens from the South 

 Carolina shrimping grounds in May 1935, only 

 5 (13.5 percent) were males; and a sample in 

 June 1935 of 18 specimens contained no males. 

 It is apparent that the percentage of males is 

 very low on the shallow coastal shrimping 

 grounds from South Carolina to northeast 

 Florida. 



Size distribution .-- Length distribution va- 

 ried widely during the year. In November the 

 females were 63 to 88 mm. long with a mode 

 at 78 mm.; the one male was 58 mm. In De- 

 cember the females were 48 to 88 mm. long 

 with a mode at 73 mm.; the three nnales were 

 43 to 58 mm. In January females were 58 to 

 83 mm. long (most were between 68 and 

 83 mm.); males were 48 to 63 mm. with a 

 mode at 53 mm. In March females were from 

 58 to 88 mm. long, with 73 to 83 mm. the 

 most abundant sizes; the one male was 63 mm. 

 The size range of females in April was 48 to 

 93 mm., with 68 to 83 mm. the most abundant 

 sizes; the 17 males were 48 to 63 mm. long, 

 with a distinct mode at 53 mm. In May there 

 was a regression in size -- females were 33 

 to 83 mm. long, with a mode at only 58 mm.; 

 the one male was 38 mm. The small June 

 sample, all females, showed a still further 

 size regression with a range from 38 to 53 mm. 

 and a mode at 43 mm. 



The largest male was 63 mm., and the larg- 

 est female 93 mm. Figure 15 shows the great 

 disparity in sizes of males and females in 

 any single sample. Joyce (1965) found a 

 similar situation for the northeast Florida 

 grounds and said, "Only three males were 

 taken above the 50-59 mm. range as compared 



14 



