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Every year, many species of marine animals, including sea turtles, marine mammals, seabirds and fish die from becoming entangled or ingesting plastic debris (Laist 1987). According to Carr (1987) sea turtles are particularly prone to eating plastics and other floating debris. Juvenile sea turtles are frequently exposed to pollution in convergence zones and most species are exposed in nearshore habitats, where they feed (Bjorndal et al. 1994). Evidence indicates that the high occurrence of non-food items in sea turtle species may be related to mistaken ingestion of plastics, due to its similarity to prey items (Plotkin et al. 1993), or even to incidental ingestion along with a prey (Tomás et al. 2002).

Figure 1. The location where the C. mydas stranded. Mole Beach is located on the island of Florianópolis, in Santa Catarina State, Brazil.

On 18 July, 2010 a juvenile green turtle (Chelonia mydas) was rescued by Projeto Tamar (Brazilian sea turtle conservation program) after stranding at Mole Beach, in Florianópolis municipal district, Santa Catarina State, Brazil (Fig. 1). On admission, the animal was measured (39 cm curved carapace length, 38 cm curved carapace width), weighed (6 kg), and received a thorough physical examination. The turtle was weak, in poor body condition, malnourished and emaciated. Clinical signs included dehydration, prostration and areflexia. Death occurred a few hours after initial supportive care. In order to determine the cause of death, a necropsy was performed on the individual. During the procedure, the turtle had its sex determined as a male by visual examination of the gonads. All coelomic organs were examined and no apparent gross pathology was noted. However, a massive amount of debris was found in its digestive tract and was apparently blocking food passage. The gastric and intestinal mucosa showed the presence of several ulcers, probably caused by the presence of debris, which could have possibly led to excess gastric acid production. The gut content was then separated according to its location: esophagus, stomach, small and large intestines. Contents were carefully rinsed in a sieve with a 1 mm mesh and marine debris was separated and dried at 50°C.

Figure 2. Comparative weight of items found in this sample and those found in 16 other turtles at the same area.

Afterwards, the samples were divided into seven categories: soft plastics, hard plastics, nylon, other plastics, latex, textile and other/unknown. Only debris items larger than 5 mm were counted. Any particles smaller than 5 mm were considered fragments of another piece, and were only weighed.

In the esophagus, 18 items were found (total dry weight: 2.30 g), in the stomach there were 308 items (34.14 g), and in the large intestine there were 3,267 items (233.16 g, see cover photo). No anthropogenic debris was found in the small intestine.

It is likely that the obstruction caused by the marine debris ingestion led this individual to death. In terms of comparative data (Fig. 2), this turtle had an enormous amount of garbage in its stomach and large intestine. The mean number of items found in the gastrointestinal tracts of other turtles (16 animals) stranded in the same area was: 9.67 items ± 15 (range: 1 - 27; total dry weight: 0.01 - 0.4 g) in the esophagus; 54.2 ± 50.5 (1 - 136; 0.02 - 16.39 g) in the stomach, 11.4 ± 19.1 (1 - 45; 0.02 - 4.81 g) in the small intestine and 128 ± 182 (6 - 732; 0.08 - 40.92 g) in the large intestine. Additionally, a comparison was made between our results and those obtained in different studies (see Table 1). Our study shows a significantly higher amount of debris than the others, although only one case report is presented here.

Table 1. Incidence and amount of debris in the digestive tracts of sea turtles reported in different studies. Sp. = species; Cc = loggerhead, Cm = green turtle, Range = range of pieces of anthropogenic debris found in the digestive tracts of sea turtles, Debris = total debris found in the digestive tracts of sea turtles. Min. size = minimum size (in cm) of anthropogenic debris considered.

Death by plastic ingestion may be caused by reduced stomach capacity (Ryan 1988); obstruction (Lazar & Gracan 2011) or exposure to toxic compounds (Bjorndal et al. 1994). According to Laist (1987), starvation is the major cause of death for animals that ingest anthropogenic debris. Nutrient absorption from food takes place as the items pass through the digestive tract. Therefore, in case of a gut blockage, the animal will starve to death. Additionally, even if there is no blockage, consumption of plastics in the place of food items may cause sublethal effects, such as partial obstruction of the gastrointestinal tract and reduction of feeding stimulus (Ryan 1988; Bjorndal et al. 1994; McCauley & Bjorndal 1999). Floating plastic debris are also known to absorb toxic contaminants from surrounding waters, increasing considerably its toxicity when ingested. These contaminants include persistent organic pollutants such as polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), nonylphenol and phenanthrene, which can become several orders of magnitude more concentrated on the surface of plastic debris than in the water column (Teuten et al. 2009).

Recently, it has been suggested that plastics could transfer harmful chemicals to living organisms (Oehlmann et al. 2009; Koch & Calafat 2009). A range of chemicals are used as additives in the manufacture of plastics, such as phthalate plasticizers and brominated flame retardants. These substances are potentially harmful and have been associated with carcinogenic and endocrine disrupting effects (Teuten et al. 2009).

Although only one case report is presented in this study, it shows how devastating marine debris can be to marine animals. Further research is required to better understand the impacts of ocean litter on sea turtle survival. Moreover, priority implementation measures should be discussed in order to prevent and reduce marine debris and its impacts on the environment. Efforts to reduce waste, increase recycling, increase use of reusable items, implement education programs and beach clean ups are also important as a means to mitigate the global marine debris problem.

Acknowledgements. We thank Wallace J. Nichols for review and suggestions. Projeto TAMAR, a conservation program of the Brazilian Ministry of the Environment, is affiliated with ICMBio (Chico Mendes Institute for Biodiversity Conservation) and is co- managed by Fundação Pró-TAMAR. Data collection was authorized by ICMBio, through special license number 14122, issued by Biodiversity Authorization and Information System (SISBIO).

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