Sea Turtles

What You Need to Know

More than half of the world's sea turtles (about 52%) have ingested plastic in their lifetime or have plastic inside their stomachs right now (VIJ, 2015). Like many other species, sea turtles are prone to continually increase their ingestion of marine debris, like plastic, as well as the issues that come along with it (Schuyler, 2014). They face foraging issues, internal injuries, chemical contamination and entanglement. Because Sea turtles are extremely mobile, they can be a vulnerable target of plastic pollution because they are exposed to move of it in different areas. Some turtles spend time on land and interact with plastic in different ways (Nelms, 2016).

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Sea turtles are more attracted to items that are flexible and translucent because it resembles prey similar to what jellyfish look like (Schuyler, 2014). There are two primary ways in which sea turtles end up ingesting plastic while foraging for food. The first way is indirectly and the second is directly (Nelms, 2016). Because jellyfish are part of the sea turtles diet, any plastic material that mimics the creature can be mistaken for food (Tilley, 2015). Items like plastic bags and polyethylene film are prime examples of what are mistaken for as food (Williams, 2010). Sea turtles are mostly visual eaters so they rely on their eyes to identify food rather than smell (Nelms, 2016). They are able to identify different colors so they are selective with what they eat but unfortunately it still leads to plastic consumption (Nelms, 2016). Worldwide, we use one trillion plastic bags each year (Ruxon, 2016). That is two million plastic bags a minute. The opportunity for sea turtles to ingest plastic bags increase as minutes go by. When debris is attached to or mixed with normal diet items, accidental ingestion can occur. 

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When plastic is ingested in sea turtles it causes internal injuries like chemical contamination, intestinal occlusion (blockage), and reproductive interruptions. All which could possibly lead to fatal consequences (Plot, 2010). Sea turtles digestive tracts are small and weak and can lead to easier blockage (Nelms, 2016). The capacity of their stomachs are compact and when plastic is lodged in there and cannot be digested, it can lead to starvation and leeching chemicals over time even when small amounts of plastic are present (Plot, 2010). Phthalates and BPA get absorbed into their tissues after residing for a long time (Nelms, 2016). Some turtles have a gas build up inside of their bodies from plastic and cannot dive down into the water until gases are removed (Ruxon, 2016). 

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Other dangers aside from ingestion are entanglement. Discarded fishing gear like fishing line and ghost nets (abandoned fishing nets in the ocean), plastic can rings, and other plastic items that can be a choking hazard are harming sea turtles (Derriak, 2002). Entanglement happens accidentally and is difficult to remove it themselves. which poses a serious threat to sea turtles (Derriak, 2002).

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Resources

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Derraik, J. G. (2002). The pollution of the marine environment by plastic debris: a review. Marine pollution bulletin, 44(9), 842-852.

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Nelms, S. E., Duncan, E. M., Broderick, A. C., Galloway, T. S., Godfrey, M. H., Hamann, M., & ... Godley, B. J. (2016). Plastic and marine turtles: a review and call for research. ICES Journal Of Marine Science / Journal Du Conseil, 73(2), 165-181. doi:10.1093/icesjms/fsv165

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Plastic threat to turtles. (2015). Veterinary Ireland Journal, 5(10), 463.

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Plot, V. Plastic Debris in a Nesting Leatherback Turtle in French Guiana. (2010). Chelonian Conservation & Biology, 9(2), 267-270.

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Ruxon, J. (Producer & Leeson, C. (Director). (2016). A Plastic Ocean [Motion Picture]. Netherlands

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Schuyler, Q. Mistaken identity? Visual similarities of marine debris to natural prey items of sea turtles. (2014). BMC ecology, (1), doi:10.1186/1472-6785-14-14

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Tilley, K. (2015). Researchers say seabirds swallowing more plastics. Plastics News, 27(24), 0023.

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Williams, C. (2010). Oceans time to take out the garbage: people may be familiar with images of individual marine animals and birds killed by discarded plastic bags and fishing lines. But the debilitating effects of marine debris on entire species is an urgent environmental issue in the International Year of Biodiversity, as Christine Williams discovered. Ecos, (157). 10.

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