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For the first time, the qualitative and quantitative characteristics of marine debris ingested by six hawksbill (Eretmochelys imbricata) and seven olive ridley (Lepidochelys olivacea) sea turtles from the Gulf of Oman coast of the United Arab Emirates were investigated. The numeric and gravimetric proportions of ingested marine debris obtained from the esophagus, stomach and intestines were quantified following categories of presumed sources, Marine Strategy Framework Directive (MSFD), rigidity, color and plastic polymer types. Marine debris was observed in 28.6% of olive ridley (x: 2.00 items; 4.83 g) and 83.3% of hawksbill specimens (x: 6.00 ± 2.32 items; 0.32 ± 0.24 g). Overall, the results of this preliminary study suggest that hawksbill sea turtles were ingesting marine debris at higher frequencies and that plastics were observed to be the most predominant debris ingested. However, non-plastic rubbish, particularly metallic fishing gear (fish hooks and fish traps), were observed to present lethal hazards for both species.

Five of the seven extant sea turtle species in the world forage on the coast of Southern Brazil at least in some stage of their life cycle. The green turtle Chelonia mydas frequently strands on beaches of Rio Grande do Sul State. The species is currently classified as vulnerable to extinction in the region, and pollution by marine debris is one of the most conspicuous threats to its conservation. In this study, we quantified and characterized plastic ingestion by juvenile green turtles in waters off the southern Brazilian coast between 2013 and 2016. We analysed the gastrointestinal content of 17 beached carcasses and registered debris ingestion in 15 individuals (88%). On average, each green turtle ingested 38.4 ± 88.5 plastic fragments. White and transparent plastic bags and plastic sheets were predominant. Our results indicate a high interaction between juvenile green turtles and marine debris off the coast of Southern Brazil.

The United Arab Emirates fisheries consist of highly diverse fish communities, and the most popular equipment used by fishermen to harvest them is a traditional baited basket fishing trap known locally as “gargoor”. Gargoors are dome-shaped traps made from galvanized steel; they have a circular supporting base and a funnel-like entrance. Unintended impacts of gargoors on marine fauna include bycatch of non-target species and, when lost, ghost fishing. However, there is very little information on sea turtle interaction with gargoors. In this paper we present two case reports from the eastern coast of the UAE of green sea turtle strandings associated with gargoor interactions. The first case report describes a turtle that was discovered trapped inside a lost or abandoned gargoor. The second case report describes another turtle that suffered from extensive perforation of the gastrointestinal tract resulting from the ingestion of 32 pieces of rusty gargoor fragments.

Mercury concentrations were assessed in the sea turtle Lepidochelys olivacea from a nesting colony of Oaxaca, Mexico; 25 female turtles were sampled, a total of 250 eggs were collected during the season 2005-2006. Higher concentrations were found in yolk fraction, while in blood and albumen mean levels were below of 0.0010μg g(-1) dry wt. On the basis of one nesting season, the maternal transfer of Hg via eggs-laying was estimated in 2.0±1.1%. According to international norms, the health of this population and its habitats is acceptable for Hg and corresponds to baseline levels of a nearly pristine environment.

To show the influence of coastal habitat degradation on the availability of food for green turtles (Chelonia mydas), we assessed the dietary preferences and macroalgae community at a feeding area in a highly urbanized region. The area showed low species richness and was classified as degraded. We examined stomach contents of 15 dead stranded turtles (CCL = 44.0 cm (SD 6.7 cm)). The diet was composed primarily of green algae Ulva spp. (83.6%). In contrast, the macroalgae community was dominated by the green alga Caulerpa mexicana. We found a selection for red algae, seagrass and Ulva spp., and avoidance for C. mexicana and brown alga Dictyopteris delicatula. The low diversity of available food items, possibly a result of environmental degradation, likely contributed to the low dietary diversity. The nutritional implications of this restricted diet are unclear.

Chelonia mydas is distributed in several regions of the world and they are common in coastal regions and around islands. Between August 2008 and July 2009, 20 specimens of C. mydas were found dead on the beaches of Ubatuba, Sao Paulo, Brazil. The stomachs were removed and anthropogenic wastes were separated according their malleability and color. Of those animals, nine had ingested marine debris. Soft plastic was the most frequent among the samples and the majority of fragments was white or colorless and was between zero and five cm. Many studies have shown a high incidence of eating waste for some species of sea turtles. The record of ingestion of mostly transparent and white anthropogenic wastes in this study strengthens the hypothesis that these animals mistake them for jellyfish. Although the intake of anthropogenic waste causes impact on the lives of sea turtles, such studies are still scarce in Brazil.

Persistent organic pollutants (POPs) and heavy metals have been reported in a number of green turtle (Chelonia mydas) populations worldwide. However, due to ethical considerations, these studies have generally been on tissues from deceased and stranded animals. The purpose of this study was to investigate the use of blood samples to estimate the tissue contamination of live C. mydas populations. This study analysed 125 POP compounds and eight heavy metals in the blood, liver, kidney and muscle of 16 C. mydas from the Sea World Sea Turtle Rehabilitation Program, Gold Coast, Australia. Strong correlations were observed between blood and tissue concentrations for a number of POPs and metals. Furthermore, these correlations were observed over large ranges of turtle size, sex and condition. These results indicate that blood samples are a reliable non-lethal method for predicting chemical contamination in C. mydas.

Concentrations of lead were assessed in the sea turtle, Lepidochelys olivacea , from a nesting colony of the Eastern Pacific. Twenty-five female turtles were sampled and a total of 250 eggs were collected during the “arribada” event of the 2005–2006 season. Considering the nesting season, the maternal transfer of lead (Pb) via egg-laying, in terms of metal burden in whole body, was 0.5%. Pb concentrations (in dry weight) in blood (0.95 ± 0.18 μg g −1 ) and egg samples (yolk, 0.80 ± 0.10 μg g −1 ; albumen, 1.08 ± 0.20 μg g −1 ; eggshell, 1.05 ± 0.20 μg g −1 ) were comparable or even lower than those found in other sea turtles. The isotope ratios ( 206 Pb/ 207 Pb and 206 Pb/ 208 Pb) in blood (1.183 ± 0.0006 and 2.452 ± 0.0006, respectively) were comparable to that of natural Pb-bearing bedrock in Mexico (1.188 ± 0.005 and 2.455 ± 0.008, respectively). According to international norms of Pb, the health of this population and its habitats is acceptable for Pb and corresponds to basic levels of a nearly pristine environment.

Sea turtles migrate to various habitats where they can be exposed to different pollutants. Bacteria were collected from turtle eggs and their resistance to antibiotics was used as pollutant bio-indicators of contaminated effluents. Eggs were collected randomly from turtles when they were laying their eggs. A total of 90 eggs were collected and placed into sterile plastic bags (3 eggs/turtle) during June-December of 2003. The bacteria located in the eggshell, albumen and yolk were examined, and 42% of the eggs were contaminated with 10 genera of bacteria. Pseudomonas spp. were the most frequent isolates. The albumen was found to be the part of the egg to be the least contaminated by bacterial infection. Bacterial isolates tested with 14 antibiotics showed variations in resistance. Resistance to ampicillin was the highest. The presence of antibiotic resistant bacteria in eggs indicates that the green turtle populations were subjected to polluted effluents during some of their migratory routes and feeding habitats. Scanning electron microscopy revealed that Salmonella typhimurium penetrated all eggshell layers.