Ingestion of marine debris in juvenile sea turtles in Abu Dhabi, United Arab Emirates

Marine plastics and other debris constitute a major threat to many marine species. Over 12 million tons of plastics are estimated to reach the oceans annually, causing adverse effects on hundreds of marine species. The Arabian Gulf is a small, sub-tropical and semi-enclosed gulf with extreme environmental conditions with high potential to accumulate marine debris. Sea turtles are especially vulnerable to plastic ingestion although data on marine plastics in juvenile sea turtles from this region is limited. Juvenile sea turtles are also vulnerable to cold stunning triggered by different environmental factors. We collected stranded sea turtles from different sites along the Abu Dhabi shoreline to characterize timing of strandings in relation to environmental factors. We also evaluated the marine debris ingested by sea turtles. Live individuals collected were kept in controlled conditions to allow them to recover. During this period, marine debris in feces were sorted and enumerated. In addition, individuals that were dead during collection were necropsied and the plastics in their gastrointestinal tracts were characterized. Industrial plastic pellets, sheet-like user plastics, and thread-like user plastics were recorded. All the live turtles (n = 55) passed plastics with their feces, and 85 % of the necropsied turtles (n = 47) had plastics in their gastrointestinal tracks. Plastic fragments constituted the largest proportion of marine debris recorded from turtles, followed by industrial pellets. We suggest that juvenile sea turtles that float for extended periods under mats of Sargassum eat vesicles or air bladders that resemble industrial pellets in their shape and size. Timing and location of strandings was associated with dominating Shamal winds in the Arabian Gulf. Condition of individuals that are cold-stunned could be further exacerbated by plastic ingestion. Long-term assessment of plastics in coastal zones is needed to better understand plastic pollution in the Arabian Gulf and to mitigate impacts on marine species.