48 58 68 78 88 98 108 118 128 138 

 43 I 53 I 63 I 73 I 83 I 93 I 103 I 113 I 123 I 133 I 143 



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43 



I 53 I 63 I 73 I 83 I 93 I 103 I 113 I 123 I 133 I 143 

 I ■ I ' I ' I ' I ' I ' I ' I ' I ' I ' 



SEPTEMBER 

 — 137 MALES =37,9% 

 •' \ 224 FEMALES =62,1% 



I ' I I I ' I ' I ' I I I < I I I I I " 



— 327MALES =40.1%. /*l M OCTOBER 



--489FEMAlES=6a2%/ \ ,' > 



.^^ 



!"' I ' I ' I ' I I I I I ' I • I ' 



.^:^: 



NOVEMBER 



296 MALES =43,4% , 



384 FEMALES =56.4% 



I ■ I < I > I < I M I I ■ I I I > 



DECEMBER 



224 MALES =49.1% 



-- 233 FEMALES=50.9% 



./.' 



\ •• 



' 53 ' 63 I 73 1 83 I 93 I 103 ' lls ' 123 ' 133 ' 143 

 48 58 68 78 88 98 108 118 128 138 



TOTAL LENGTH (MM.) 

 Figure 13.— Continued. 



Heavy recruitment of young shrimp to the 

 fishing grounds during summer and fall is 

 consistent with sea bobs being most abundant 

 on the Georgia fishing grounds during late 

 fall and winter. 



Ovary development .-- Table 10 presents data 

 on development of ovaries of sea bobs for all 

 months but May. All females captured in 

 January and February had undeveloped ovaries. 

 In March 87.7 percent were undeveloped, 11.4 

 percent were developing, and 0.9 percent were 

 yellow. In April 16.1 percent were undevel- 

 oped, 38.8 percent developing, 38.7 percent 

 ripe without attached spermatophores, and 6.4 

 percent ripe with attached spermatophores. 

 In June there were no undeveloped ovaries, 

 1.8 percent were developing, 21.5 percent 

 yellow, 9.0 percent ripe without attached 

 spermatophores, and 67.7 percent ripe with 

 attached spermatophores. In July through Oc- 

 tober, the relatively high percentage of shrinnp 

 classified as having developing ovaries prob- 

 ably included spent shrimp, which we did not 

 distinguish from those with developing ovaries. 

 In July 19.7 percent were developing, 37.1 

 percent yellow, and 43.2 percent ripe with 

 attached spermatophores. In August, with the 

 influx of young shrimp onto the grounds, 7.6 

 percent were undeveloped, 21.9 percent de- 

 veloping, 18.3 percent yellow, 3.1 percent 

 ripe without spermatophores, and 49.1 percent 

 ripe with attached spermatophores. In Sep- 

 tember 33.2 percent were undeveloped, 24.4 

 percent developing, 6.5 percent yellow, 18.1 

 percent ripe without attached spermatophores, 

 and 17.8 percent ripe with attached sperma- 

 tophores. For October 62.3 percent were 

 undeveloped, 26.5 percent developing, 1.8 per- 

 cent yellow, 8.6 percent ripe without attached 

 spermatophores, and only 0.8 percent ripe 

 with attached spermatophores. For November 

 92.2 percent were undeveloped, 6.8 percent 

 developing, 0.5 percent yellow, and 0.5 per- 

 cent ripe without attached spermatophores. 

 In December all females had undeveloped 

 ovaries. 



The smallest fennale with ripe ovaries 

 and attached spermatophore was 63 mm. 

 long. 



If the occurrence of females with ripe 

 ovaries and attached spermatophores is used 

 as a criterion for spawning activity, spawning 

 begins as early as April, peaks in June, July, 

 and August, and tapers off in the fall. There 

 is still considerable spawning in September, 

 but only occasional spawning in October, and 

 none from November through March. This 

 seasonal progression follows very closely 

 that for white shrimp (Lindner and Anderson, 

 1956). 



13 



