TOTAL LENGTH-CARAPACE LENGTH RELATION- 

 SHIP 



A plot of the mean carapace lengths for each 

 of 28 male and 36 female, 5-mm. total-length 

 classes suggested that the relationship between 

 the two attributes could be best described by a 

 simple exponential (fig. 6). Up to a total length 

 of about 150 mm. the relationship for both sexes 

 appears nearly identical and is, for all practical 

 purposes, rectilinear. Beyond this length, how- 

 ever, definite curvature indicates that increases 



240 



220- 



200- 



w p 140 



10 20 30 40 50 60 



CARAPACE LENGTH 



(mm.) 



in carapace length (c) do not keep pace with 

 increases in total length (I). Note also in the 

 larger shrimp a marked sex differential in the 

 total length-carapace length ratio. Thus, for 

 shrimp of the same total length, females will have 

 a greater carapace length than males, the difference 

 increasing with size. 



Table 3. — Distribution by sex and relative size of pink 

 shrimp sampled during 1960-61 in south Florida for 

 weight and length measurements 



FIGURE 6. — Total length-carapace length relationship 

 in pink shrimp. 



For pink shrimp not exceeding 170 mm. total 

 length (equivalent to 16 headless-count), the 

 information provided in figure 6 will permit, 

 graphically or mathematically, reasonably accu- 

 rate estimation of total length from a known 

 carapace length. Although precision diminishes 

 somewhat above this limit, resulting estimates 

 will still be sufficient for most purposes. 



Linear conversions indicated in table 1 and 

 elsewhere in this study employed the information 

 given in figure 6. 



Weight-Length Relationships 



Plots of data categorized as above showed 

 weight to be a simple power function of length. 

 Either the fitted curves or equations for total 

 weight (w) as a function of carapace length 

 (fig. 7), and as a function of total length (fig. 8) I 

 may be used to estimate weight from either I 

 linear dimension with reasonable precision and U 

 accuracy. Close examination revealed some sea- I 

 sonal variation in the relationships, but not I 

 enough to be of practical significance. Sex I 

 differences are clearly evident in each case with i 

 the disparity being particularly prominent in the I 

 total weight-carapace length ratios. Among 

 -liiin 1 1> having the same carapace length, males, on ' 

 the average, not only possess a greater total ll 

 length but are heavier than females. It follows, I 

 conversely, that in individuals of the same total I 

 length, the males will weigh less than the females M 

 and have a shorter carapace. These differences | 

 should be borne in mind whenever metric conver- . 



322 



U.S. FISH AND WILDLIFE SERVICK 



