males and 98-108 mm. for females in June to 

 123 nnm. for n-iales and 138 nnm. for females 

 in August (fig. 9). The modes then decreased, 

 however, to 113 mm. for males and 128 mm. 

 for females in September -- which I attribute 

 to a migration of much of the population from 

 the shallow coastal fishing grounds. As in 

 Georgia, it is difficult to link the size in- 

 creases from June to August with actual 

 growth rates because the shrimp were ap- 

 parently rapidly leaving the fishery by August 

 and September. 



68 78 88 98 108 118 128 138 U8 158 168 178 

 63 I 73 I 83 I 93 I 103 i 113 i \73 i 133 | 143 | 153 i 163 i 173 , 183 



11 

 10 

 9 

 8 

 7 

 6 

 5 

 4 

 3 

 2 

 1 

 

 11 

 10 

 9 

 8 

 7 

 6 

 5 

 4 

 3 

 2 



U 



« 11 



9 



I I I I f I 1 1 I I 1 I I I r I I 1 I ' I I I 



AUGUST 

 — 232 MALES =42.: 

 --316 FEMALES =57 



42.3% / \ ^' \ 



5 7.6% /• \ / \ 



../ / 



I I I I I I I I I I I 1 . 1 I I I I I I I ' I I 

 j\ I \ SEPTEMBER 



- 91 MALES =39.4% 

 -140 FEMALES = 60.7''<' 



, I I ■ I ■ I ■ I ■ I ' I ' I ' I ' I ' I ' I > 



63 ' 73 ' 83 ' 93 ' 103 ' 113 ' 123 ' 133 ' 143 ' 153 ' 163 ' 173 ' 183 

 68 78 88 98 108 118 128 138 148 158 168 178 



TOTAL LENGTH (MM.) 



Figure 9.— Size distribution and sex ratios of brown 

 shrimp on South Carolina outside fishing grounds, by 

 month, June to September, 1933-34. 



Ovary developnnent .-- Annong shrimp cap- 

 tured in outside waters, all were undeveloped 

 in June and July except for one in a developing 

 stage in July; in August 98.5 percent were 

 undeveloped and the rest were developing; and 

 in September 98.6 percent were undeveloped 

 and the rest were developing (table 4). The 

 smallest shrimp with developing ovaries was 

 148 mm. Ovary development during August 

 and September was far less advanced on the 

 South Carolina grounds than on the Georgia 

 grounds. 



Recruitment of postlarval brown shrimp 

 into South Carolina inshore waters occurs 

 from January to May (Lunz, 1963), These 

 larvae could originate from spawning some- 

 time during the fall or winter, but the spawn- 

 ing site is unknown. 



Northeast Florida 



Brown shrimp appear on the shallow north- 

 east Florida shrimping grounds in about April 

 and reach peak abundance about July. By 

 September few remain on the grounds. 



Size distribution .-- Figure 10 gives the size 

 distribution and sex ratios of brown shrinnp 

 for outside waters of the shallow coastal fish- 

 ery for May through September. 



The few shriimp taken in May were consid- 

 erably smaller than those found in Jvane, when 

 the mode was 123 mm. for males and 133 mm. 

 for females. The mode for fennales dropped 

 to about 128 mm. in July and August, but the 

 mode for nnales remained at about 123 mm. 

 In September the modes were 133 nnnn. for 

 males and 138 mm. for females -- not much 

 different from the sizes in June. This unusual 

 variation in size distribution from June to 

 September is apparently the result of con- 

 tinued recruitment of small shrimp from the 

 inside nursery grounds to the shallow coastal 

 fishing grounds and migration of parts of 

 the population (chiefly large shrimp) from 

 the coastal fishing grounds to more offshore 

 areas. 



For years the abrupt decline in abundance 

 of brown shrin-ip during September to October 

 on the shallow coastal shrimp grounds of the 

 south Atlantic coast has led to speculation that 

 there must be a concentration of large in- 

 dividuals sonnewhere on the Continental Shelf 

 beyond the coastal fishing grounds. Until 1965 

 no such concentration had been discovered. In 

 January 1965 the BCF R/V Oregon located 

 commercial concentrations of very large brown 

 shrimp in 55 to 59 m. (30-32 fathoms) south 

 of Cape Kennedy, and portions of the com- 

 mercial shrinnp fleet worked these grounds 

 for several months. When the Oregon returned 

 to these offshore grounds in March 1965 to 



