Protocol for Processing Sea Turtle Bones for Age Estimation

Skeletochronology, or the histological preparation and analysis of skeletal growth marks in bones, has proven to be a useful tool in estimating the ages and growth rates of sea turtles. The ability to successfully carry out this technique can allow researchers to fill existing data gaps and detect temporal changes in vital rates. This report is intended to be a guide for reproducing the methods that have been refined over many years by NOAA Fisheries’ Southeast Fisheries Science Center researchers at the NOAA Beaufort Laboratory for the purpose of estimating the ages and growth rates of sea turtles. We describe each step in sufficient detail to guide histological processing of sea turtle bones so that the lines of arrested growth (LAGs) that delimit the outer edges of individual, annual skeletal growth marks may be visible in decalcified, stained bone cross sections. Bone histology is a technique that is not always straightforward and can present difficulties, which is why we include a troubleshooting section with a pictorial guide to common issues encountered and our suggestions for correcting course. The focus of this guide is on histological processing of juvenile and adult sea turtle humerus bones, as they are the primary structure typically used for age and growth analyses; however, brief methods for processing scleral ossicle bones and hatchling humeri are included.

Goshe, L.R., L. Avens, M.L. Snover, and A. A. Hohn. 2020. National Sea Turtle Aging

Laboratory Protocol for processing sea turtle bones for age estimation. U.S. Dept. of

Commerce, NOAA. NOAA Technical Memorandum NMFS-SEFSC-746, 49 p. DOI:10.25923/gqva-9y22