122 



Fishery Bulletin 100(1) 



100 



100 



10 



20 



30 40 



Estimated age (yr) 



50 



Figure 5 



(A) Bootstrap distributions of estimated age at observed SCL generated by resam- 

 pling the data for aging rate to humerus diameter 100 times and by applying the 

 spline-integration method to each bootstrap replicate. iBi Corresponding distribu- 

 tion of growth curves, described by the bootstrap mean growth cui-ve (line) and the 

 approximate 50'^f and 95^c confidence intervals for predicted mean length at age 

 (outer and inner edges of solid region). 



Age- and length-specific growth rates 



The box plots of the Sl-estimated carapace growth rates 

 (Fig. 8) indicated relatively fast growth for smaller tur- 

 tles, a reduced growth rate remaining fairly constant 

 over intermediate length classes, and declining growth 

 rates in larger, mature turtles. Mean carapace gi'owth rate 

 declined from 4.4 cm/yr for turtles in the 20-30 cm SCL 

 group to less than 1 cm/yr for mature turtles in the 90-100 

 cm group, and remained around 2.0-2.5 cm/yr for imma- 

 ture juveniles in the intermediate length groups (Table 

 2, Fig. 8). Differences in mean growth rate among the 

 intermediate length groups were not significant. The aver- 

 age growth rates predicted by first differences of the SI- 

 based growth model (Fig. 9) indicated a similar pattern, 

 as expected, showing a decrease in growth rate during the 

 first decade of life (when Hawaiian gi-een turtles are still 



foraging in the open ocean or in the early years of their 

 residence in inshore habitats), relatively constant growth 

 during the next 15-20 year interval, and a further decline 

 in growth rate as the turtles approach 30 years of age. The 

 gi-owth rate appears to remain low in older turtles. 



Discussion 



Age and growth-rate estimates 



Age estimates by both methods indicate an age range 

 of 4-49 years for the Hawaiian green seaturtles in their 

 coastal habitats. The pelagic juvenile (28.7 cm SCL) in our 

 sample was about four years old (4.1 and 3.3 yr by CF and 

 SI methods, respectively). The smallest juveniles (35-37 cm 

 SCL) in coastal waters were 6 to 9 years old by the CF 



