Nates and Felder: Growth and maturation of Lepidophthalmus stnuensis 



531 



abundance per clutch (Fig. 5, B 

 and D), was maintained at par- 

 ticularly elevated levels from 

 February through at least April 

 and perhaps May. 



Growth and sexual maturation 





30 



10 

 



£ 14 



G 



12^ 

 



B 



~ 0.16 



E 

 E 



- c 



u 



E 

 E 



o 



3 

 E 



0.12- 



0.08 



Size at sexual maturation in both 

 males and females of the sampled 

 population was evident in rela- 

 tive growth changes of the major 

 chela. Asymmetry of the first 

 pereopodal chelae was clearly 

 evident in both sexes and did not 

 show bias for right or left hand- 

 edness in random subsamples 

 (left:right handedness 23:27 for 

 males, 25:25 for females; /i=50 

 per sex). The value of this feature 

 as a secondary sex character was 

 suggested initially by the much 

 heavier general appearance of 

 the appendage in large males 

 than in females of approximately 

 the same size, and sexual differ- 

 ences in allometric growth were 

 documented subsequently by re- 

 gression analyses of morphologi- 

 cal measurements ( Fig. 6; Tables 

 1 and 2). 



Relative growth rate in the 

 chela width of males increased in 

 animals that had reached a mean 

 carapace length of at least 11.3 

 mm, as estimated by linear-lin- 

 ear piecewise polynomial regres- 

 sion analysis (Fig. 6A). Indepen- 

 dent regression analysis of males 

 larger and smaller than this size 

 by reduced major axis revealed 

 significant differences in slopes 

 for those data sets ( Table 1 ), even 

 though the two values for this 

 positive allometric growth did 

 not differ significantly when com- 

 pared as allometric coefficients 

 (Table 2 ). When fitted by reduced 

 major axis, regression slopes for 

 both prematuration and postma- 

 turation phases of growth in female chela width (Fig. 

 6B) differed significantly from those for both growth 

 phases in males, although there was far greater dif- 

 ference between the sexes in the postmaturation 

 phase. Relative growth in the chela width of females 



Figure 3 



Quarterly measures of salinity, growth, and reproductive indices in sampled Co- 

 lombian populations of Lepidophthalmus sinuensis, January 1992 through De- 

 cember 199.5; for A-C, vertical lines define 95% CI; for D-E, vertical lines define 

 range. (Al Morning surface salinity Ippti at the farm intake pump station in the 

 upper estuary, e.xpressed as mean of daily measures throughout each quarter; (B) 

 mean CL of mature Oil mm CLI males (closed circles) and females (open circles) 

 in sampled populations; (C) relative ovarian development (OW/CL); (D) percent- 

 age of ovigerous individuals among females; (E) percentage of juveniles (<10.00 

 mm CLi. 



became significantly less positive beyond a carapace 

 length near 10.8 mm. The negative allometric growth 

 (coefficient <1 ) for this postmaturation phase in females 

 (Table 2) differed significantly from the strongly posi- 

 tive allometric growth in postmaturation males. 



