Threats To Sea Turtles

In our previous articles, we started to explore the different species of sea turtles in Costa Rica. 

To remind ourselves, they are: olive-ridley, green, leatherback, hawksbill, and loggerhead. 

Unfortunately, each of these 5 species are threatened with extinction. From bycatch to habitat loss, turtles face a whole manner of threats.

In this article, we'll be exploring some of the key factors attributing to the decline of sea turtles in Costa Rica. I've seen each of these threats directly, so the aim of this article is to spread awareness. 

The Role of Humans

Many of the current threats sea turtles face are directly attributed to human activity. But, this shouldn't come as a surprise anymore.

What's more, many of the threats facing sea turtles are intrinsically linked.

Take a beachside condo development, for example - a growing problem in regions on the Pacific Coast of Costa Rica. 

Nesting beaches will be destroyed. That's a given. But noise and light pollution will increase, as will plastic waste from a surge in people. Artificial lights disorientate hatchlings, causing them to travel inland and away from the ocean. Increased tourism will see the addition of water activities, such as boat or jet ski excursions, increasing the risk of collisions. 

And that's just the start. Let's explore in more detail the main threats sea turtles in Costa Rica currently experience.

1. Climate Change

The sex of a turtle is determined by the temperature

Let's start with the biggest, and perhaps least understood.

Climate change is a very real problem that is affecting nearly all life on our planet. Including our own.

Yet, the science behind climate change is not concrete and the implications climate change will have on sea turtle populations are still being researched.

Firstly, climate change is affecting the sex of turtles.

When laying eggs, a female will create an egg chamber by using her hind flippers. These chambers can be up to a metre deep. The temperature within these chambers influence the sex of the developing offspring. In zoology, we refer to this as temperature-dependant sex determination.

If the egg chamber is 27.7°C or below, turtle hatchlings will become male. Above 31°C, the clutch will be female. Fluctuating temperatures between this range yield a mixed clutch of both males and females.

However, with the current global temperature rise, as a result of anthropogenic climate change, we are noticing that more and more sea turtle nests are producing all-female clutches. With such a massive sex skew, the survival of sea turtles may be in jeopardy.

However, there are some other, indirect problems arising from climate change.

As sea temperatures rise, frequency and severity of tropical storms are likely to increase.

The power behind these storms can erode vital habitats essential for the survival of sea turtles, such as coral reefs or nesting beaches. Increased rainfall may flood nests, accelerating bacterial and fungal infestations, drastically reducing hatching success rate.
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Climate change will affect global weather patterns, which may, in turn, affect the circulation of ocean currents in which sea turtles use to navigate and migrate. 

The honest answer is that we still don't know the full extent to which climate change will affect sea turtles. But it's not looking good. 

2. Plastic

Even on a remote Costa Rican beach, plastic pollution is everywhere

​Yes, plastic has been a big problem for many years. And what has been done about it? Not much.

Despite claims from major corporations about how they've cleaned up their act, it is estimated that over 380 million tonnes of plastic is being produced each year! Much of this is single use plastic that will end up in our oceans.

According to experts, some 500 billion bags are used worldwide. Oh, but it's fine, because now many large supermarket chains, especially in the U.K, charge 10p per bag. It is a greenwashing conspiracy that feeds capitalistic greed.

It's a touchy subject for me, can you tell?

I have witnessed first hand the effects of plastic. Walking along deserted Costa Rican beaches, far from any town, plastic litters the shorelines. Cutlery, footwear, straws, bottles, bags, clinical waste. You name it, I saw it.

In the ocean, plastic is broken down into near microscopic pieces by the UV rays of the sun, and the abrasive action of the waves.

Unfortunately, many marine species - both big and small - consume these microscopic particles, until plastic has made its way up the food chain.

Large predatory fish, such as tuna and sharks, as well as sea mammals and turtles, are the ones that are affected most of all. Known as bioaccumulation, toxins from plastic build up in an organism faster than they can be broken down. The toxins magnify the higher up the food chain they go and can cause serious health problems for a range of animals.

Turtles are significantly at risk from plastic pollution. Not only do they unknowingly ingest microplastics, they actively eat plastic bags - simply because plastic bags look remarkably similar to one of the main prey species of some turtle species: jellyfish.

I have carried out necropsies on olive ridley, loggerhead and green sea turtles. In nearly all cases, plastic had been found either lodged within their trachea, causing suffocation, or within the stomach, causing starvation.
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Plastic pollution is a global problem. We are simply addicted to it, at the detriment of our planet.

3. Discarded Fishing Gear

Discarded fishing gear was responsible for the death of this green turtle

Discarded fishing gear, otherwise known as ghost nets, are a serious threat to marine life. Ghost nets include any form of lost or discarded fishing gear, much of which remains unseen.

Ghost nets are a form of plastic pollution, contributing up to 800,000 tonnes of marine waste. It is possibly the deadliest form of marine plastic. And that's why discarded fishing gear deserves its own placement on the list. 

As it floats in the water column, it can snag and ensnare a range of wildlife from marine mammals, fish, seabirds and turtles. The entangled animals, unable to feed or escape, face a painful death through either starvation, suffocation or exhaustion.

In the US alone, it is estimated that 250,000 sea turtles become entangled or killed by ghost nets every year.
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Discarded fishing gear also damages important marine ecosystems, such as coral reefs, in which sea turtles (as well as a plethora of other marine life) rely on for rest and cleaning.

4. Habitat Loss

When we talk about habitat loss, it's easy for our minds may wander to rainforest deforestation. I'm certainly guilty of it.

But habitat loss can occur in every ecosystem of our planet - including the ones sea turtles so heavily rely on.

As Costa Rica becomes an ever more popular tourist destination, more and more infrastructure is being constructed to accommodate the increase in tourism.

And what areas are commonly affected? Beaches!

But coastal development is a broad category, encompassing a range of human activities - including the beachfront development of homes, hotels, restaurants and roads. Oftentimes, sea defences are also implemented to protect these new developments, such as sea walls.

Such landscape alterations negatively affect historic nesting grounds, either by destroying the nesting beach completely, or creating barriers that render the beach inaccessible. If a female turtle does manage to nest, beach litter and light pollution can harm hatchlings.

However, coastal development isn't the only type of habitat loss affecting sea turtles.

Certain fishing practices, such as trawling, destroy seagrass meadows - the critically important foraging grounds of green sea turtles. It is these grass meadows that give the green turtle their characteristically green fat.
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Other species of sea turtle, such as the loggerhead, use the seagrass meadows to forage for invertebrate prey.

If it's out of sight, is it out of mind? 

5. Bycatch

Conservationists putting out nets to monitor turtles

Bycatch is a global epidemic affecting all megafauna of our oceans.

Put simply, bycatch is the accidental capture of a non-target species. In this case, turtles!
Where there is fishing, there is bycatch.

Across the globe, thousands of miles of fishing lines are deployed each day. Effective though they may be at catching target species, such as fish, they are near invisible in the water column and can snag any animal swimming in its path.

Every day, marine mammals, birds and reptiles die needlessly, often as a result of drowning via entanglement. For those that are caught and hauled up onto fishing vessels, they are unceremoniously thrown back overboard, weak and injured, and often to their demise.
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In the USA alone, it is thought that 12,ooo sea turtles die as a result of accidental bycatch each year. However, the actual figure may be much, much more.

Ironically, some conservationists in Costa Rica use in-water nets to capture sea turtles to collect vital metric data. The nets are loose enough for the turtles to surface, and scientists regularly monitor the nets to ensure the turtles aren't ensnared for too long. I have personally joined researches carrying out this method.

6. Direct Harvesting

A turtle hatchery offers a safe place for turtle eggs to develop away from poachers

Despite being a protected species in much of the world, sea turtles are still commercially hunted for their eggs, meat and shell.

In Costa Rica, egg poachers are a prevalent problem - an issue I have come face to face with. In fact, a previous colleague, Jario Mora Sandoval, was brutally murdered by poachers on a Costa Rican beach. He was just 26 years old.

Poaching is a ludicrous industry. With each egg selling for $1, and with up to 100 eggs in a single nest, turtle egg poaching is easy money to be made.

However, in Costa Rica, the collection and sale of turtle eggs is illegal and strictly monitored. Only one area, Playa Ostional, is licensed to trade in turtle eggs - and regulations are fierce.

But it's not just eggs targeted.

Hawksbill turtles were readily hunted for their ornate shells, which was used to create jewellery and tourist trinkets - leading to a near collapse in the Costa Rican population.

Fortunately, hawksbill turtles are now listed as a protected species and, under CITIES, it is illegal to trade any turtle products on the international market.

Final Thoughts

In Costa Rica, 5 species of sea turtles can be found.

Despite being a much-loved, bucket-list animal, all species of sea turtles are threatened with extinction. Climate change, habitat loss and plastic pollution are serious threats negatively affecting sea turtle populations. 
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Today, many conservation groups are conducting important research on sea turtle species. The results will help scientists conserve these ancient reptilian species for generations to come.

At Cecropia Travel, we partner with many of these organisations. This means our guests can directly become involved in conservation during their travels. Reach out to our team today to find out more. ​