Spatiotemporal occurrence of loggerhead turtles (Caretta caretta) on the West Florida Shelf and apparent overlap with a commercial fishery

Abstract

Information on the spatial and temporal distribution of protected marine species is critical for the development of conservation strategies. We examined a 12-year dataset describing the postnesting residence areas of 81 adult female loggerhead turtles (Caretta caretta) on the West Florida Shelf (WFS) in the northeastern Gulf of Mexico. The aggregation of loggerheads on the WFS represents at least four US recovery units for this protected species. We identified several seasonally persistent residence areas that were shared by multiple loggerheads on the WFS. The majority (69%) of individuals remained within a discrete residence area throughout the tracking period. We placed our results within the context of a related fishery management concern — loggerhead bycatch within the bottom longline component of the Gulf commercial reef-fish fishery. We characterized loggerhead residence areas and compared that information with fishing activity. Our results provide information on the distribution of WFS loggerhead residence areas and the extent to which residence areas overlap with areas of high fishing effort. Loggerheads were present year-round on portions of the WFS, within or near to areas with high fishing effort. Interactions among loggerheads and fishing activities could be reduced by conservation management strategies that consider these spatial and seasonal patterns of occurrence.