An Evaluation of Histological Techniques Used in Skeletochronological Age Estimation of Sea Turtles

Skeletochronological analysis was used to compare stained and unstained cross sections of humeri from Kemp's ridley (Lepidochelys kempii) and loggerhead (Caretta caretta) sea turtles to determine if the 2 histological techniques yielded an equal number of visible lines of arrested growth (LAGs). Stained sections viewed at high magnification under a compound microscope revealed the presence of closely spaced and splitting LAGs, resulting in a greater number of individual LAG counts for these sections when compared to unstained and stained sections viewed at a lower magnification under a dissecting microscope. Prior studies have shown that some of these closely spaced LAGs are annual, and therefore the inability to detect such marks could result in a downward bias in age estimates.