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Sea Turtles And Pollution

Sea turtles face pollution throughout every stage of their lives – as eggs, hatchlings, juveniles, and adults. Pollution is caused by pollutants such as plastics, oil spills and petroleum (as well as other petroleum products), toxic metals, polychlorinated biphenyls (PCBs),  industrial & agricultural runoff such as untreated waste, fertilizers, pesticides, and other chemicals.

Pollution can generally be grouped into plastic pollution, oil and chemical pollution, light and noise pollution, and pathogens. Pollution is one of the biggest threats that sea turtles face.

These pollutants can have an immediate effect on the well-being of the chelonians or the harmful chemicals can accumulate in the tissues and lead to immunosuppression. Sea turtles and pollution is, therefore, a topic worth discussing.

Table of Contents

Types of pollution sea turtles face
Plastic pollution
Oil pollution
Agricultural and industrial runoff
Light and noise pollution
What can be done?
Organizations Protecting Sea Turtles from Pollution
Infographic (Printable)
Frequently asked questions

The huge disadvantage here is that all marine turtle species are threatened.

The green turtle, the Kemp’s ridley, and the hawksbill are classified as critically endangered. The leatherback is classified as endangered. The loggerhead and the olive ridley are classified as vulnerable.

There are many reasons why sea turtles are endangered, but obviously, pollution is one of those bigger reasons. These classifications are provided by the IUCN (International Union for Conservation of Nature) and can be found on the IUCN Red List.

The flatback has no classification or status on the IUCN Red List because of data deficiency. The species is however considered endangered in Australia.

Types of Pollution Sea Turtles Face

Sea turtles face all manners of pollution. These include plastic pollution, oil pollution, noise and light pollution, agricultural and industrial runoff, and the spread of pathogens such as fibropapilloma.

1. Plastic Pollution

Sea turtle swimming with plastic and has a plastic bag in its mouth
Sea turtle swimming with plastic and has plastic bag in it’s mouth

Plastic pollution has a huge negative impact on the wild population of marine turtles. In fact, all marine turtle species are affected. You may be wondering how that is the case.

It’s because plastic debris resembles several foods that these chelonians feed on, including jellyfish, marine vegetation, and other animals. The chelonian may think it is consuming nutritious food only to ingest harmful plastics.

Apart from ingesting the plastic, turtles can become entangled in plastic waste that can trap them underwater and ultimately drown them. It is estimated by WWF that at least 1000 turtles die annually from being entangled in plastic debris.

A large number of wild sea turtles ingest plastic. It’s estimated that about 50% of all sea turtles have ingested some sort of plastic.

Sea turtles can choke on plastic waste, become injured internally, and can potentially starve to death if these particles become lodged or block their food intake. Plastics can even make it difficult for the turtle to dive by creating pockets of air inside the chelonian’s gut.

Why Do Marine Turtles Eat Plastic?

Close up of Green Sea turtle eating plastic material
Close-up of Green Sea turtle eating plastic material

Turtles ingest plastic bags, in particular, because it resembles jellyfish which is the main food of several marine turtle species such as the leatherback, olive ridley, and Kemp’s ridley. Sea Turtles are also known to eat fishing nets as they resemble seaweed which is a staple food for flatbacks, green turtles, and others.

How Does Plastic Pollution Negatively Impact Sea Turtles?

There are several ways in which plastic negatively impacts the lives of sea turtles. For starters, plastic can cause cuts and injuries to the intestinal walls when ingested.

Plastic can also create blockages in the digestive tract of the reptile.

Even if the plastic doesn’t damage the digestive tract or cause a blockage it can imitate the sensation of being full. This will result in the turtle eating less real food. Since plastic has no nutritional value, the turtle can starve to death or become malnourished.

Apart from ingesting the plastic, the reptile can become entangled in it. Juveniles and hatchlings can easily injure themselves when they become entangled with even a small piece of plastic waste on the beach.

By getting tangled up baby sea turtles can potentially lose limbs and even die. That being said, small turtles aren’t the only ones at risk. Adults that get caught in nets and other waste can also end up injuring themselves when trying to get free.

Discarded fishing nets are a huge threat to marine turtles. As many of you may already know, fisheries bycatch is often considered to be the highest threat to marine turtles.

Bycatch occurs when marine turtles are caught in fishing equipment meant to catch other species. Even when not in use, fishing nets threaten the lives of turtles.

Discarded fishing nets/equipment can trap marine species underwater. Unlike fish, turtles breathe air and need to surface often to breathe. When trapped underwater, turtles can unfortunately drown.

What Do The Statistics State?

According to research done by USC (Commonwealth Scientific and Industrial Research Organization) and CSIRO (Commonwealth Scientific and Industrial Research Organisation), there is a 22% probability of death if a marine turtle ingests a single piece of plastic.

This probability increases to 50% if the turtle has ingested 14 pieces of plastic debris. The conclusion came after sampling nearly 1000% dead turtles. This sample also included dead turtles that washed up on shores across Australia.

The global estimate of sea turtles that have ingested debris is around 52%.

As you may have guessed, deaths from being entangled in discarded fishing gear are much higher since turtles will drown if they are unable to escape in time.

According to research conducted by UoE (University of Exeter), when caught in discarded fishing gear, the death rate is 91%.

What Can We Do To Stop Plastic Pollution?

There is a lot that we can all do to ensure that plastic pollution is reduced.

Here are some steps you can take:

Use reusable containers/bags

Plastic bags are usually discarded after just one use. Why not invest in a reusable bag such as a tote bag? This will help to cut down on plastic/rubber bag usage. Also, plastic soda cups are often used once. So are the plastic straws that come with these cups.

The same can be said after coffee cups and many other take-over beverages and foods. It is a good idea to buy reusable cups, food containers, water bottles, and such for your groceries, foods, and drinks. This will cut plastic pollution.

Say no to plastic silverware

Plastic cutlery is often used just once before they are discarded. If you do decide to have a takeaway, why not reject the plastic cutlery that comes along?

Pick up your trash

When out on the beach, take your waste with you. If you see something (plastic bag, wrapper, can, etc), pick it up.

If we all do our part, it will add up and have a significant impact. Even if you are the only one doing it, you may be saving the life of a turtle. Lead by example.

2. Oil Pollution

Eastern box turtle covered in oil
Eastern box turtle covered in oil

Oil spills seem to be quite a common occurrence in recent times all over the world. Oil spills have a serious negative impact on the environment and marine life. The marine turtle is just one of the many creatures that are negatively affected by oil spills.

Turtles can be found across the ocean and live in many different parts, from the shores to the continental shelf where many of them feed. They can also be found in the open ocean.

How Does Oil Pollution Negatively Impact Sea Turtles?

According to NOAA (National Oceanic and Atmospheric Administration), all aspects of oil spills, from the spill to the cleanup, harm marine turtles.

Hatchlings can be found in the open ocean where they drift and float in sargassum (these are large brown seaweeds that float like islands atop the open ocean). Here the turtles feed, hide, and grow. When the turtle is older, they then move to the shoreline and continental shelf.

This is where the turtle lives until death. Females and males alike travel to their natal beach to mate. While males and females mate offshore, females venture onto the shore to nest.

This is why you have beaches around where areas are protected for the hatchlings.

Because of the wide range of ecosystems that turtles Inhabitat, an offshore oil spill often affects all the habitats of marine turtles. Oil spills in the open sea can find themselves on the continental shelf and finally onto the shore.

Breathing difficulties

As already mentioned, turtles breathe air, though they can breathe through their cloaca a little bit. This makes them vulnerable to oil spills. Thick oil slicks atop the waters make it difficult for the turtle to breathe. The continuous trio to the surface also means that the turtle gets covered in thick oil.

Saragassum contamination (Seaweed)

Hatchlings never go deeper than a few feet and are much more exposed to the oil slicks. The currents and winds mean that sargassum and oil slicks often come to the same convergence zones.

Of course, turtles aren’t the only species affected. In fact, all species that lie in the sargassum are all negatively affected.

The sargassum may even sink when contaminated by the oil and depressants. This leaves the hatchlings exposed to predators and also reduces their food source.

Nest contamination

On shore, oil contaminates nesting turtles, hatchlings, and nests.

On the ocean, juveniles and larger individuals are at risk of inhaling oil vapors. Since everything is covered in oil, it means the prey they eat makes them take in oil as well.

The currents and winds also create ocean fronts that consolidate the oil spill into one large area but also pull in the sargassum communities too. This in turn leads to prolonged floating oil exposure.


Juveniles and hatchlings will then also inhale the oil vapors and ingest the oil, which leads to overheating and getting stuck, both of which are fatal.

Food contamination

The prey that the turtles feed on also dies in large numbers when exposed to the heavy oils and the dissolved oil components.

Cooked alive

Another threat is that the thick black oil can even cook the turtles as it is heated by the sun, potentially leading to death.


The oil also makes it difficult for the turtle to go about their daily activities and can even cause them to die from exhaustion.

Cleanup Efforts

Even the clean-up can be harmful to the chelonians.

The response boats and ships can collide with and kill turtles. Burning oil spills is one way to clean up the oil spills and protect water and air quality. However, this also negatively affects the inhabitants.

Oil skimming activities also negatively affect the turtles. The presence of artificial light from the ships/vessels can also consume the turtles and hatchlings that navigate using the lights from the night sky.

The Dangers Of Inhaling And Ingesting Oil

The turtle inhales polycyclic aromatic hydrocarbons (PAHs) which are a toxic oil compound. These toxic compounds make their way to the lungs and liver of the turtles.

This compound can then make its way into the eggs of nesting mothers which then negatively interferes with the developing hatchlings. This can lead to the death of the unhatched turtles.

Oil irritates the mucus membrane of the digestive tract, lungs, mouth, and eyes. The oils can also interfere with the heart function and breathing of the turtle.

The esophageal papillae which make it easy for turtles to swallow food become covered in oil, making it more difficult for the turtle to feed. The esophageal papillae also help to expel water from the turtle’s throat.

Oil also affects the prey and food of the turtle. The oil can kill and contaminate foods including algae, seagrass, seaweed, jellyfish, crustaceans, and fish.

What Is Being Done? (Oil Spill Cleanup)

Workers try to clean up oil that has washed ashore
Workers try to clean up oil that has washed ashore

Once the oil spill has occurred, the turtles need to be rescued and protected. Here are a few things that are done to protect these marine reptiles.

Government agencies including Oil Spill Removal Organization (OSRO) and other wildlife groups perform aerial surveys to ascertain the extent of the damage to marine life.

Using boats and dip nets, affected chelonians are collected out of the oil and assessed. This is to determine the extent of the damage.

Rescuers also patrol and monitor the shores for affected turtles. The nesting habitats are also inspected and monitored to ensure that the nests are safe and unaffected.

When needed, the reduced turtles are admitted to wildlife rehabilitation centers where the oil is cleaned from the turtle and the turtle can be nursed back to health.

3. Agricultural And Industrial Runoff

Runoff pipe discharging waste and water
Runoff pipe discharging waste and water

Agricultural and industrial runoff is a huge issue that affects turtles all over the world, not just marine turtles. These runoffs can be pesticides, fertilizer, untreated waste, and several others.

The runoff can be fatal to marine reptiles with studies showing that runoff is linked to the development of diseases and tumorous growth as discovered by research by Duke University, the University of Hawaii, and NOAA in 2014.

How Does Agricultural And Industrial Runoff Negatively Impact Sea Turtles?

Farm runoff in Hawaii is known to cause tumors. This data is based on the study by Duke University, the University of Hawaii, and NOAA.

Some chemicals in the runoff are the main culprits here. These chemicals find their way into the macroalgae/algae in the ocean.

As you may already know, several species of sea turtles feed on algae. The nitrogen in the chemical runoff has been shown to promote tumors on the internal organs, flippers, and eyes of sea turtles.

The disease that the chemical runoff promotes is Fibropapillomatosis. As reported in the journal, scientists have been able to find a direct correlation between human nutrient inputs and the effect on reef ecosystems and wildlife including green sea turtles.

This disease is known to cause life-threatening tumors. In fact, Fibropapillomatosis is known to be the leading cause of death in green sea turtles.

It isn’t just the nitrogen that is the issue but the excess nitrogen that the algae stores as a result of the excess nitrogen in the ecosystem introduced by the chemical runoff.

This excess nitrogen is stored as arginine. One of the algae species that stores a higher amount of arginine is Hypnea musciformis.

Hypnea is a genus of red algae (Rhodophyta) that is considered and Hypnea musciformis is of that genus. Hypnea musciformis is known to be invasive and highly opportunistic and is common off the coast of Maui.

The marine turtles that eat these algae with excess arginine are known to have as much as 14 times more arginine in their body than turtles that feed in less polluted ecosystems.

Other amino acids that are found in excess in the algae include glycine and proline. These amino acids are also linked to the development of human cancer tumors.

4. Light And Noise Pollution

Light pollution from New york times square
Light pollution from New york times square

Light pollution and noise pollution are detrimental to sea turtles, especially nesting females and hatchlings. Both nesting females and hatchlings rely on natural lights to navigate and return safely to the sea.

Artificial lights have been known to disorient turtles that come to shore as well as hatchlings. Additionally, artificial lights deter adults from nesting on the beach.

How Does Light Pollution Negatively Impact Sea Turtles?

Light is essential to the navigation of sea turtles. As the turtles use the night light to navigate.

Additionally, sea turtles also use a night light to navigate toward the sea. These hatchlings move towards the brightest area which turns out to be the ocean as it reflects light off the night sky.

If there are a lot of artificial lights close to the beach, the hatchling may confuse artificial lights for the ocean. The turtle can die from vehicular accidents, dehydration, predation, and fatigue.

According to studies done on Cabo Verde, specifically Boa Vista island, lighting can reduce nesting success by 20% in loggerheads. This is because the entire orientation and duration of the nesting are impacted.

Additionally, the lights also increase the activity of animals that prey on offspring.

How Does Noise Pollution Negatively Impact Sea Turtles?

Noise pollution can deter turtles from nesting as they feel threatened.

However, a more serious issue is temporary hearing loss caused by underwater noise pollution. This pollution is due to offshore constructions as well as passing ships.

Temporary underwater hearing loss can last for a few minutes to several days. This hinders the navigation of the turtles as well as their ability to detect predators and prey.

According to research done by Andria Salas of Woods Hole Oceanographic Institution and her collaborators, temporary hearing loss can be an indicator of permanent hearing loss or damage.

What Can Be Done?

There is a lot that can be done to reduce light pollution and its effect on sea turtles. This is essential if you live near a beach where turtles nest.

There may already be laws and ordinances in place that require you to turn off beachfront lights during the nesting seasons. Although these ordinances are not always obeyed or enforced, you can do your part.

Here are some things that you can do to reduce light pollution:

  • Install turtle-safe lights. These include red lights as they produce lights that are part of the tint portion of the light spectrum. This is better for the hatchlings and nesting females. Install LPS lights (low-pressure sodium-vapor lighting).
  • Report disoriented hatchlings to law enforcement or turtle conservancies nearby.
  • Cover windows that can be seen from the beach. This will limit the lights that can be seen from the beach. Additionally, you should also tint those windows.
  • Additionally, turn off lights that can be seen from the beach and light fixtures that can be seen from the beach should be shielded.
  • As already mentioned, turn off beachfront lights during nesting season, if you are required to by law.

Organizations Working to Protect Sea Turtles from Pollution

Many organizations, governmental and non-governmental, are working on finding solutions to sea pollution. Several of those have already been mentioned in this article.

Some of these include:

Several other organizations such as SeaWorld, WWF, Olive Ridley Project, Sea Turtle Conservancy, and even local organizations such as Loggerhead Marinelife Center, Gumbo Limbo Nature Center, and Project Biodiversity (Projeto Biodiversidade) all help with the cleanup of affected turtles when the need arises.

Many of these organizations also help to educate the general populous about sea pollution and how it negatively affects marine life and eventually humans as well.

Legal Protection

Sea turtles are also offered legal protection under the U.S. Endangered Species Act of 1973, commonly known as ESA. only the flatback is not protected under the ESA which isn’t surprising as this turtle is only endemic to Australia and isn’t found in any of the waters of the United States.

Additionally, the species is listed in the CITES Appendix I which protects them from trade and importation. The species are also protected under the IUCN.

Wildlife Refuges/Reserves

There are several special restricted areas around the world where turtles are protected by governments.

An example of this is the Archie Carr National Wildlife Refuge. This 20.5-mile-long beach is the most important loggerhead nesting site in the western hemisphere.

Some other refugees in the Americas include the Pearl Cays Wildlife Refuge (PCWR) – for hawksbills, Estero Padre Ramos Natural Reserve, and Chacocente Wildlife Refuge in Nicaragua; Ostional National Wildlife Refuge, Bacalar Chico Marine Reserve, Camaronal Refuge, Marino Las Baulas National Park, Tortuguero National Park, and Gandoca-Manzanillo Wildlife Refuge in Costa Rica; Belize Barrier Reef Reserve, and Belize Barrier Reef Reserve in Belize; and Coiba National Park in Panama.

Marine Zoos

Close-Up Shot of an Orca at the SeaWorld by Soly Moss
Close-Up Shot of an Orca at the SeaWorld by Soly Moss

Many marine zoos in the world help to protect sea turtles from pollution.

These parks such as SeaWorld care for thousands of rescues. For instance, in 2010, Sea World in Orlando cared for about 130 turtles affected by oil pollution.

These zoos also care for, incubate, and hatch eggs. For instance, SeaWorld located in San Diego hatched 21 green turtle eggs in 2003 and 82 green turtle eggs in 2009.

Sea Turtle Tracking

Rescues are often tracked after rehabilitation.

This allows marine biologists to better study these reptiles and gather valuable data on the species as data on sea turtles is still quite limited. This is due to the inaccessible nature of the creatures.

Mote Marine Laboratory & Aquarium track sea turtles via satellite to gather data on their behavior and movement. The Hubbs-SeaWorld Research Institute is another institute that tracks rehabilitated sea turtles.

Screenshot of Dukes North Atlantic Turtle Tracking of Sea Turtles
This is a screenshot of Dukes North Atlantic Turtle Tracking of Sea Turtles. Check the tool out

Some other institutions that track and study sea turtles include Sea Turtle Conservancy, Whitney Laboratory for Marine Bioscience (UF), Duke North Atlantic Turtle Tracking, and Marine Turtle Research Group (UCF).


Sea Turtles And Pollution Infographic

Frequently Asked Questions

How many sea turtles die from plastic every year?

The number of turtles that die from plastic debris can be difficult to determine as we are unable to determine the exact number of turtles out in the wild and we are unable to examine almost all the sea turtles that die in the wild each year.

However, about 1000 sea turtles are documented dying from ingesting plastic debris each year. These are only the documented cases and as such make up a tiny percent. Also, more than 1,000 sea turtles are estimated to die each year from drowning after getting entangled in plastic (such as discarded fishing nets).

What are the threats to sea turtles?

Turtles face several threats. As you may already know, pollution isn’t the only threat that sea turtles face.

The main threats to these chelonians include habitat degradation (which is caused by human activities such as building construction, sand extraction, beach armoring, and several others), bycatch in fisheries (which is caused by poor fishing methods), overharvesting of the eggs, meat, and shells of the turtles, and pollution.

The overharvesting of the eggs, meat, and shell of turtles are often the biggest threat to turtles all over the world. The eggs and meat of sea turtles are for human consumption.

Why do turtles eat plastic?

Turtles eat plastic because it resembles the foods that they eat. Plastics can resemble jellyfish which is one of the staple foods of several species such as the leatherback, olive ridley, and Kemp’s ridley. The turtle may think it is eating jellyfish only to end up causing serious harm to itself.

Discarded fishing nets also resemble seaweeds that several turtles eat. Flatback (which is endemic to only Australia) and green turtles are known to eat large amounts of seaweed. These turtles can confuse fishing nets for seaweed.

How many sea turtles are left?

Estimating the number of sea turtles on earth is very difficult as the oceans of the world are huge and sea turtles can be found in most oceans of the world. Recent estimates, as reported by the Olive Ridley Project, state that there could be almost 6.5 million sea turtles out there.

Some species such as the hawksbill are critically endangered and global populations could be as low as 57,000. Also, species, including flatback and Kemp’s ridley, with limited geographic ranges could have global populations of less than 10,000.

Wrapping up

Sea pollution has a lot of detrimental effects on sea turtle species all over the world all of which add up to the endangered nature of these magnificent animals. Pollution can lead to the degradation of the habitat and also directly affect the turtles.

Noise pollution can lead to hearing loss, both temporary and permanent, and disorient the turtles. Light pollution negatively impacts the navigation capacity of the turtles as these turtles rely on the night sky to navigate. Hatchlings also rely on the reflection of the night sky on the ocean to find their way to the ocean.

Plastic pollution leads to turtles ingesting plastic and getting trapped in plastic debris. Sea turtles of all ages and species are affected.

Oil pollution also leads to the ingestion of harmful chemicals and the inhalation of oil vapors. Both of which are fatal to the turtles. Oil slicks also impede the movement of the chelonians.

Industrial and agricultural runoff also have serious consequences. Chemical runoff has been linked to an increase in tumorous growth in green turtles found in Hawaii.

The chemicals from the runoffs are absorbed by algae in reef systems. Turtles feed on this algae.

Sea turtles and pollutants shouldn’t go hand in hand but this isn’t the case currently. A lot is being done to protect these endangered creatures.

Humans need to stop polluting the oceans if sea turtles are to survive and thrive.

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