growth (model 2) has limited applicability in studies of wild turtle demography. However, the

fact that several biochemical indices for blood (including DNA concentration and RNA:DNA

ratio) were significantly correlated with growth suggests that further calibration of these assays

for application to growth estimation is warranted. Indeed, 55% of the variance in body mass

growth was predicted using only CI and concentration of DNA in the blood. This coefficient of

determination represents a loss of only 13% of the maximal predictive power achieved by the

best model I developed. Both CI and blood DNA content are easily measured with limited

disturbance to the animal. In combination with morphometric measurements, the blood cells of

C. mydas may therefore allow for the development of minimally invasive techniques for

estimating recent growth rates in this endangered species.