Density of Loggerhead Turtles in the Mediterranean Sea

The Mediterranean Sea subpopulation, which ranges throughout the entire Mediterranean basin, is listed as least concern but experiences significant threats in the region including bycatch in fisheries, climate change, coastal development, and marine pollution. Broad-scale patterns of distribution and abundance can provide regional managers a tool to effectively conserve and manage this species at basin and sub-basin scales.

Here NUWC uses aerial and shipboard line transect survey data collected between 2003 and 2018 to estimate density and abundance throughout the Mediterranean Sea using distance sampling methodology. A spatial density model estimating loggerhead density, abundance, and distribution across the Mediterranean Sea was generated as a long-term annual average. The model was adjusted for availability bias using dive data from loggerhead turtles tagged with time depth recorders from multiple regions within the Mediterranean Sea.