o — 



Oo 



>- z 



MEAN MEDIAN LENGTH (V2 cm) 



LATITUDE 29°00' TO 29°39-N 



Figure 8. — Mean median length of females by latitude 

 and depth (see text for explanation). 



FISHERY BLXLETIN: VOL. 69, NO. 2 



shrimp and the deptli from which they were 

 caught. Thi.s figure also indicates that the aver- 

 age size of shrimp is usually, but not always, 

 larger in that part of the St. Augustine Grounds 

 north of lat 29°39' N than between lat 29°00' 

 and 29°39' N. 



We are not certain why shrimp tend to be 

 smaller in the central than in the northern por- 

 tion of the St. Augustine Grounds unless most 

 of the recruitment is in the central area. If 

 shrimp also are larger in the southern portion 

 of the grounds (as our meager data from that 

 area suggest), the obvious conclusion is that 

 most of the recruitment occurs in the central 

 portion of the grounds; otherwise, it may be that 

 recruitment is from the south. 



SIZE AT MATURITY 



FIRST DEPTH SECOND DEPTH 



. 274 -320 METERS . 322 -366 METERS 



050-175 FATHOMS) {I 76 - 200 FATHOMS) 



. 368-411 METERS . 413 + METERS 



(201 - 225 FATHOMS) (226+ FATHOMS) 



o< 



Z 25 



MEAN MEDIAN LENGTH ( 1/2 c 



FIRST DEPTH 



Figure 9. — Mean median length of females by depth and 

 latitude (see text for explanation). 



latitude zone, with the first or shallowest depth 

 class as the abscissa and the next succeeding 

 depth class as the ordinate. The marks for each 

 latitude zone appear to fall in a random fashion 

 about the 45° lines; con.sequently there was no 

 apparent relation between the length of the 



The terminal ampoules were small and poorly 

 developed in most males less than about 125 mm 

 long but were large and prominent in specimens 

 greater than this length. This observation sug- 

 gests that sexual maturity in the males is reached 

 at about 125 mm total length. 



Development of the ovaries, began in most 

 females at about 136 mm total length, but ma- 

 turity was not attained until they were about 

 155 mm long. In the random samples, all of 

 the 1,327 females that had attached spermato- 

 phores were ripe. Of this number only 55 or 

 about A'^'r were less than 151 mm long. The 

 smallest ripe shrimp with attached spermato- 

 phores (three individuals) were in the 136- to 

 140-nun size class. 



Lindner and Anderson (1956) demonstrated 

 that female Penaens setifems underwent cer- 

 tain morphometric changes on attaining matur- 

 ity. It is evident from Figures 10 and 11 and 

 Appendix Table 3 that the regressions of cara- 

 pace length on total length for both male and 

 female royal red shrimp also show changes in 

 slope at about the lengths at which each sex 

 reaches maturity. Male royal red shrimp (Fig- 

 ure 10) demonstrate a change in slojje at the 

 midpoint of the 126- to 130-mm class interval, 

 which agrees with field observations on the size 

 at which the males reach maturity. 



320 



