Marine debris knows no boundaries: Characteristics of debris accumulation in marine protected areas of the Florida Keys.

Marine debris is a persistent and pervasive threat worldwide including inside marine protected areas (MPAs). To assess marine debris accumulation rates and potential impacts, we counted and evaluated trap, non-trap fishing gear, and non-fishing debris in unprotected areas and MPAs with different management boundary regulations in the Florida Keys (USA). Analyses identified that neither MPA type nor size were strong drivers of debris density and that debris densities were not statistically different between unprotected areas and MPAs. Non-fishing and non-trap fishing gear debris densities were potentially related to unexplored local differences in human behavior, while trap debris density was likely associated with oceanographic forces that transported traps into the MPAs. Overall, our results suggested that the drivers of marine debris accumulation for each debris category were different and may vary with each individual MPA, and that marine debris is not constrained by MPA boundaries.