Cooperative Fish and Wildlife Research Units Program:
Education, Research and Technical Assistance for Managing Our Natural Resources


Investigating trends in turtle abundance from REEF data

March 2022 - December 2025


Participating Agencies

The Reef Environmental Education Foundation (REEF) collects citizen science surveys for a variety of marine species. REEF volunteers use the Roving Diver Technique (RDT), a visual survey method specifically designed for volunteer data. The only materials needed are an underwater slate and pencil, a good reference book, and access to the internet to submit the data online. The data is collated using a log scale for abundance where things are single (n=1), few (n=2-10), many (n=11-100), and abundant (n=101+). Recently Dr. Dan Greenberg developed a Bayesian model which can create area- and species- specific abundance estimates through time based on REEF RDT surveys. The abundance estimates have been used for species that are data-limited (e.g., Goliath Grouper in the southeastern US) and have been compared to scientific abundance estimates (e.g., coral reef fishes in Florida). This project seeks to build estimates of abundance for a variety of turtles species(Green turtles, Loggerhead turtles, and Hawksbill turtles) in multiple locations (Hawaii, Tropical Atlantic, and the Tropical Eastern Pacific). We hope to collaborate with scientists from NOAA to compare the abundance indices derived from REEF data to other indices and indicators of turtle populations.