Smith and Kostlan: Growth of Etehs carbunculus from sagittal otolith radius 



467 



data for Hawaii and French Polynesia, 

 these reached values of L^, far above 

 lengths of fish captured in these re- 

 gions throughout the history of their 

 fisheries. For NMI and Vanuatu, non- 

 linear regressions tended towards un- 

 limited L M . These results were similar 

 to those of Ralston and Williams, indi- 

 cating that the primary limitation on 

 accurate growth estimation was prob- 

 ably the range of fish lengths sampled. 



However, the present regressions 

 differ from those of Ralston and Wil- 

 liams' in that they are derived from 

 age estimates for measured otoliths 

 and fork lengths, rather than from 

 estimated lengths at equally spaced 

 intervals along the otolith radius. 

 Ralston's method produces an artifi- 

 cially broader and more uniform sam- 

 ple. This is evident in that the one 

 region (NMI) for which the previous 

 estimate was able to converge showed 

 an inadequate fit by the present 

 method, which is consistent with the 

 clustering of data points in the middle 

 of the size range (Fig. 2). Experimen- 

 tal fitting to a Gompertz curve was 

 done initially, but it was found that 

 lack of fit by either method was more 

 attributable to the variance in age esti- 

 mates and the narrow range of fish 

 sizes than to the choice of a growth 

 curve. The regression of otolith radius 

 on fork length was allometric for all 

 regions examined, so it is not surpris- 

 ing that somatic growth rate is repre- 

 sented as well by the von Bertalanffy 

 curve. 



The von Bertalanffy growth con- 

 stant (K) for the best curves for each 

 region were in the range of 0.129- 

 0.137 for Vanuatu, 0.179-0.310 for 

 NMI, 0.064-0.190 for Hawaii, and 

 0.039-0.145 for French Polynesia. The 

 highest value of K = 0.464 for NMI, 

 estimated by log-linear regression, 

 was arbitrarily left out of the range for 

 this region as being abnormally high. 

 Any of the estimates for NMI could 

 well be excluded on the basis of the r 2 

 values. Estimates of natural mortality 

 (M) for these K values using the relationship for snap- 

 pers and groupers by Ralston (1987) and for various 

 taxa by Ricker (1973) are listed in Table 5. These K 



estimates agree with those summarized by Manooch 

 (1987) for other species of lutjanids, including several 

 of the subfamily etelinae. 



