Plastic ingestion by sea turtles in Paraíba State, Northeast Brazil

Abstract

ABSTRACT. Currently, plastics are recognized as a major pollutant of the marine environment, representing a serious threat to ocean wildlife. Here, we examined the occurrence and effects of plastic ingestion by sea turtles found stranded along the coast of Paraíba State, Brazil from August 2009 to July 2010. Ninety-eight digestive tracts were examined, with plastic found in 20 (20.4%). Sixty five percent (n = 13) of turtles with plastic in the digestive tract were green turtles (Chelonia mydas), 25% (n = 5) were hawksbills (Eretmochelys imbricata), and 10% (n = 2) were olive ridley (Lepidochelys olivacea). More plastic was found in the intestine (85%) than in other parts of the gastrointestinal tract. We observed complete blockage of the gastrointestinal tract due to the presence of plastic in 13 of the 20 turtles that had ingested plastic. No correlation was found between the curved carapace length (CCL) and the number or mass of the plastic ingested items. Significant differences were found between the intake of hard and soft plastic and the ingestion of white/transparent and colored plastic, with soft and white/transparent plastics being more commonly ingested. This study reveals the serious problem of plastic pollution to sea turtles at the area. KEYWORDS. Marine debris ingestion, gastrointestinal blockage, Chelonia mydas, Eretmochelys imbricata, Lepidochelys olivacea.RESUMO. Ingestão de plástico por tartarugas marinhas no estado da Paraíba, Nordeste do Brasil. Atualmente, os plásticos são reconhecidos como um dos principais poluentes do ambiente marinho, representando uma séria ameaça para a vida marinha. Neste trabalho, nós examinamos a ocorrência e os efeitos da ingestão de plástico por tartarugas marinhas encontradas encalhadas ao longo da costa do estado da Paraíba, Brasil, de agosto de 2009 a julho de 2010. Noventa e oito tratos gastrointestinais foram examinados e plásticos foram encontrados em 20 (20,4%). Sessenta e cinco por cento (n = 13) das tartarugas com plástico no trato gastrointestinal eram da espécie verde (Chelonia mydas), 25% (n = 5) eram da espécie pente (Eretmochelys imbricata) e 10% (n = 2) eram da espécie oliva (Lepidochelys olivacea). Foi encontrado mais plástico no intestino (85%) do que em outras partes do trato gastrointestinal. Observou-se o completo bloqueio do trato gastrointestinal, devido à presença de plástico, em 13 das 20 tartarugas que ingeriram plástico. Não foi encontrada correlação entre o comprimento curvilíneo de carapaça (CCC) e o número ou massa dos itens plásticos ingeridos. Diferenças significativas foram encontradas entre a ingestão de plástico rígido e flexível e entre a ingestão de plástico branco/ transparente e colorido, com os flexíveis e brancos/transparentes sendo ingeridos com mais frequência. Este estudo revelou o grave problema da poluição por resíduos plásticos para as tartarugas marinhas nesta área. PALAVRAS-CHAVE. Ingestão de lixo marinho, bloqueio gastrointestinal Chelonia mydas, Eretmochelys imbricata, Lepidochelys olivacea.

Biases and best approaches for assessing debris ingestion in sea turtles, with a case study in the Mediterranean

“…This is supported by the lack of difference in the type of ingested debris among turtle groups (finding categories) which indicates that all turtles select the same type of debris resembling the same type of prey. Specifically, the ingested debris was mostly composed of white or transparent plastic sheets or fragments, as also observed in other studies (e.g., Camedda et al, 2014;da Silva Mendes et al, 2015;Poli et al, 2015;Schuyler et al, 2012).…”

“…This mortality was not regularly reported by other studies (Schuyler et al, 2014a) and it seems to be more relevant for green (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) (e.g., Bjorndal et al, 1994;Guebert-Bartholo et al, 2011;Poli et al, 2015;Santos et al, 2015). Mortality induced by debris was estimated at 10.7% over a large sample of green turtles in Brazil, where plastic amounts as low as 0.5 g caused death and with half of the observed deaths induced by b2.5 g of plastic (Santos et al, 2015).…”

“…With few exceptions (Macedo et al, 2011;Shaver, 1998), in most studies (Table 4) this aspect was not considered, and turtles suffering from cold-stunning, from other illness, entangled, or stranded because of debris ingestion were included in the analyses. In some cases, the body condition was mentioned in relation to this problem, but then all turtles were considered altogether in the analysis of occurrence (e.g., Guebert-Bartholo et al, 2011;Poli et al, 2015).…”

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Assessing plastic debris in aquatic food webs: what we know and don’t know about uptake and trophic transfer

“…Plastic ingestion has also been correlated with reduced body weight or condition (Harper and Fowler 1987;Donnelly-Greenan et al 2014;Lavers et al 2014). Finally, ingested plastics can lead to blocked gastrointestinal tracts (Poli et al 2015;Nelms et al 2015), and have been reported as the cause of death in stranded wildlife (Jacobsen et al 2010;Brandão et al 2011).…”