150 1 



Immature. Spent or Resting 

 n = 3853 



Total Length |mm| 



FIGURE 4. — Size of female Squilla empusa by maturity stage. Maturity stages are described in Table 2. 



Sex Ratios 



Females made up 541 of the overall catch of S. 

 empusa and were significantly more abundant 

 than males ( \ 2 = 71.53, P 0.05). Except in Au- 

 gust 1979 when only two individuals were caught, 

 females predominated and made up 52-631 of the 

 500-1,000 S. empusa usually caught each month. 

 Sex ratios did not differ significantly between 

 depths (x 2 = 1.82, 4 df, P > 0.05). Sex ratios gener- 

 ally were equal from 30 to 80 mm, but females 

 increasingly predominated at larger sizes (Fig. 6). 

 Sex ratios did not differ significantly from a 1:1 

 ratio until S. empusa exceeded 80 mm (Table 3). 



Maximum Size and lntrayear Variations in Size 



Typical maximum size reached by S. empusa in 

 the northwestern Gulf is 110-115 mm. The largest 

 of 9,400 specimens we captured was only 132 mm, 



TABLE 3. — Observed sex ratios and chi-square 

 statistics for Squilla empusa divided into 10 mm 

 length groups, July 1979-June 1980. Asterisks 

 indicate significant x 2 at a = 0.05. 



99% were <110 mm, and 99.5% were <114 mm 

 (Fig. 7). 



Size compositions showed little change 

 throughout the sampling period. Except for the 



422 



