Delphi survey to assess the spatial distribution of sea turtles in the Pacific Ocean

To understand interactions between turtle and fisheries, the Pacific Community (SPC) required quantitative maps of the distribution of turtle through the Pacific Ocean. A web-based tool was developed that allowed experts to draw maps of the distributions of four species of turtle: green (Chelonia mydas), leatherback (Dermochelys coriacea), loggerhead (Carea carea), and olive ridley (Lepidochelys olivacea). Each of these species is ranked as either endangered or vulnerable, and the reduction of fisheries bycatch mortalities has been highlighted as a priority for their conservation.

From the survey responses, a spatially-explicit Bayesian model was used to derive relative abundance of the turtle throughout the Pacific. Survey particants mapped abundance using five categories (from absent to maximum abundance), and the analysis fitted a continuously valueddensity to the responses. In addition to a mean value, the analysis allowed for uncertainty in the distributions to be plotted, highlighting regions where the particpants disagreed. An iterative Delphi process was used that allowed survey particpants to update their responses in lighht of the combined analysis.

The web application allowed for the spatial mapping to be carried out efficiently, with the results being used by the Western and Central Pacific Fisheries Comission in a Workshop on Joint Analysis of Sea Turtle Mitigation Effectiveness