The Danger of Plastic and Marine Litter to Sea Turtles
Updated: Apr 22
Earth is home to seven different types of Sea Turtle, the Hawksbill, Loggerhead, Leatherback, Green, Flatback, Kemp's Ridley and Olive Ridley.
Every turtle is fundamental to marine ecosystems and has been for over 100 million years. Not only do they help to maintain the health of coral reefs, they also balance ocean food chains and help to keep seagrass healthy by grazing.
Further to this, they provide a habitat for an array of aquatic life such as algae, crustaceans and barnacles, transporting them during migration and sheltering them from predators.
We rely on them too, as we are also part of the Earth's systems, but there are many who have deeper connections to the turtles, with many indigenous tribes believing them to be their ancestors. We use them today as a powerful symbol of the oceans as they are a reminder of the wonder and beauty of the oceans, but also, of the pollution and waste that is dumped into them every year.
Our overuse of and discarding of plastics threaten aquatic life, in particular Sea Turtles. According to a study by Jambeck et al., (2015), an estimated 5.7 and 15.4 million tonnes of plastic entered the oceans in 2016.
Ingestion of plastic marine litter, in particular with Green Turtles is at an extremely high rate where the Green Turtles typically feed in shallow regions and coastal areas during the earlier stages of their life (Lebreton et al., 2017) where litter is abundant.
Whilst many sea turtles are herbivores that feed on ocean plants, some of the species of Sea Turtles also feed on jellyfish and shellfish.
The Leatherback and the Loggerhead have a jellyfish heavy diet in particular and so are susceptible to eating items that resemble jellyfish such as plastic bags and balloons.
Research completed by Rizzi,. et al (2019) measured the intake of ocean litter over 86 different sea turtles. In the study, 49 of the 86 turtles had ingested plastic marine litter which is a staggering 57%.
The types of material that were ingested included plastic, rubber, wood, paper and cloth and it was seen that plastic had been ingested by all of the different species. Only green and loggerhead sea turtles had ingested the other materials.
In green turtles, party balloons were the most non plastic item ingested and occured in almost half of the green turtle species tested in the study.
The research identified the number of fragments eaten by each type of turtle and where those fragments originated from.
Between 2013 and 2017, 552 fragments of plastic packaging were found in 29 Green Turtles along with 173 fragments of plastic bags. 171 fishing line fragments were also present and 16 fragments of straws.
The study found fragments of a staggering range of items from bottle caps to cigarette butts. (Rizzi,. et al, 2019). In 84% of the Green Turtles, 84% of the litter had begun to biodegrade inside them.
Why can't the turtles regurgitate the waste?
Sea Turtles cannot regurgitate the waste because of the way in which turtles eat and the mechanisms of their bodies.
The lining of a turtles throat is filled with papillae, fleshly spines that can constrict and retract to allow for food to pass directly into the oesophagus, allowing for food to remain inside, and for water to flow back out. Because these papillae work in one direction, the turtle is unable to regurgitate the litter, leading to deadly health conditions.
Plastic pollution in the ocean kills millions of marine life every year. For turtles, their biology makes them particularly susceptible to death from plastics. Plastic debris can puncture a turtles stomach, cause gas leading to starvation where the turtle becomes idle and floats, and plastics clog the internal body. According to Santos et al. (2015) only 0.5g of litter is sufficient to cause death by blocking the gastro-intestinal tract of Green Turtles.
It is so important that we learn to treat the oceans with respect, but it is a problem that doesn't seem to be changing, despite the warnings and literature available.
91% of turtles entangled in fishing gear die. To stop this, we need to stop consuming fish.
52% of turtles globally have eaten plastics. To stop this we need to stop purchasing items in plastic packaging, and where unavoidable, recycle properly.
Eating one piece of plastic leads to a 22% chance of death for turtles, a fate unavoidable for them.
According to the WWF, Research shows that for every kilogram of plankton in the ocean, there are six kilograms of plastic. If we carry on as usual, this could mean there will be more plastic than fish in the world’s oceans by weight in 2050.
If you would like to help additionally to changing daily habits, then check out SEETURTLES here who are a company dedicated to protecting sea turtles. They offer adoption packs as well as volunteering opportunities with their Billion Baby Turtles campaign.
Thanks for reading,
The Climate Corner
J.R. Jambeck, R. Geyer, C. Wilcox, T.R. Siegler, M. Perryman, A. Andrady, R. Narayan, K.L. LawPlastic waste inputs from land into the ocean
Science, 347 (6223) (2015), pp. 768-771, 10.1126/science.1260352
L.C. Lebreton, J. Van der Zwet, J.W. Damsteeg, B. Slat, A. Andrady, J. ReisserRiver plastic emissions to the world's oceans
Nat. Commun., 8 (2017), p. 15611, 10.1038/ncomms15611
Rizzi, M., Rodrigues, F., Medeiros, L., Ortega, I., Rodrigues, L., Monteiro, D., Kessler, F. and Proietti, M., 2019. Ingestion of plastic marine litter by sea turtles in southern Brazil: abundance, characteristics and potential selectivity.Marine Pollution Bulletin, 140, pp.536-548.
R.G. Santos, R. Andrades, M.A. Boldrini, A.S. MartinsDebris ingestion by juvenile marine turtles: an underestimated problem
Mar. Pollut. Bull., 93 (1–2) (2015), pp. 37-43, 10.1016/j.marpolbul.2015.02.022
Wwf.org.au. 2020.Plastic Pollution Is Killing Sea Turtles: Here's How. [online] Available at: <https://www.wwf.org.au/news/blogs/plastic-pollution-is-killing-sea-turtles-heres-how#gs.3yjezp> [Accessed 22 April 2020].
Largest Sea Turtle Image - https://ocean.si.edu/ocean-life/reptiles/what-largest-sea-turtle-sea-turtle-size-comparison-chart
Leatherback Sea Turtle Throat Image - https://metro.co.uk/2016/05/23/this-animals-mouth-is-terrifying-but-can-you-guess-what-it-is-5899683/
Sea Turtle Image & Baby Sea Turtle with Plastic Bag Image - https://www.seeturtles.org/ocean-plastic