How the Climate Crisis Threatens Loggerhead Sea Turtles
This summer, I finally crossed something off my bucket list: participating in loggerhead sea turtle conservation in Kefalonia with Wildlife Sense. As an animal lover, I have always been passionate about the marine reptile. Because of my eye-opening experience in Kefalonia, I have discovered a new side to my passion – sea turtles’ science, behavior, and obstacles in the way of their survival.
My hope is that more people become aware of the tremendous amount of effort that goes into protecting loggerhead sea turtles. Due to the climate crisis, plastic pollution, and unsustainable human behavior, the efforts of Wildlife Sense are especially important in this critical time for the endangered species.
Related Topics: The Ocean Cleanup – Overfishing, Climate Change, and Hunger – Animal Welfare – Juan Oliphant: Underwater Photographer and Conservationist
Loggerhead sea turtles have astonishing evolutionary characteristics. The females can choose when to use sperm from the males to fertilize her eggs, and she has multiple chambers in her uterus to store sperm. This means that there may be multiple fathers in one clutch of eggs, which I find astonishing. Loggerhead sea turtles also have pili in their mouths which constantly expel saltwater that they drink (since they are hyper-osmoregulators). Like some marine birds, sea turtles have salt-secreting glands which cause them to look like they are crying, but really, they are just maintaining their internal salt concentrations.
Sea turtles are typically solitary reptiles that only interact with others when mating or during territorial fighting. However, in Kefalonia during the harbor shift, this is not the case. As part of our monitoring, the conservation team goes to the harbor where fishing boats arrive in the morning to sell fish to tourists and locals. Because of the vast amount of fish available to the turtles, many congregate in a small area, causing fights to break out between them. This is an unnatural behavior. Sea turtles have been around for 200 million years, and in that time, they have roamed the oceans where there is plenty of space and food, resulting in limited competition. But, in their new anthropogenic environment, this is no longer the case.
Competition over food and space is only the start of the problems loggerhead sea turtles face. Contrary to many people’s knowledge, fish are not healthy for them. In the wild, fish make up a minute proportion of their diet, with the majority taken up by seagrass, bivalves, crustaceans, and jellyfish. To sea turtles, eating fish every day is like humans eating McDonald’s every day – extremely unhealthy and dangerous. When tourists see turtles surrounding fishing boats, they understandably assume that fish is what the turtles normally eat. One of my main jobs as a volunteer on the harbor shift was to educate tourists who regularly went to the harbor for no other reason than to feed fish to turtles. There were many occasions when I had to politely explain that this was not the right thing to do. The unknowing sea turtles rely on volunteers to educate the locals.
The Dangerous Harbor
Unfortunately, fishing boats coming to the harbor every day have a catastrophic effect on turtles. As more turtles realize that there is food to be easily found by the fishing boats, they soon begin to associate boats and humans with food. However, they do not know that boats have giant propellers which could kill them with a single strike, and, why should they? Their ocean habitat has been free of anthropogenic machinery for 200 million years. Because they get fed by tourists and fishermen, they begin to think, “hmm, there’s a boat there, they might give me some food too!” This is a very dangerous association to make. While I was in Kefalonia, there was a record number of dead turtles washed up on the beaches, some of whom were unlucky victims of a boat strike. Clearly, the simple act of feeding a turtle fish in the harbor can snowball into a dangerous cycle that many are in the dark about.
Global Warming Affects Sea Turtles
Global warming is another major player in the decline of sea turtle populations. Sea turtle sex is determined by the incubation temperature of the nest at the middle of the incubation period (about 55 days). Below 29ºC, all the eggs of one nest are male, and above, all are female. At exactly 29ºC, there will be a 50/50 split. Global warming means that more nests will begin to hatch 100% female, which is detrimental to the survival of the species, as, without both sexes, it cannot be sustained. At the moment, this has not become a major problem, as across several beaches the temperatures will be sufficiently variable. However, in the future, conservationists may need to artificially alter nest temperatures, possibly by dripping water over them.
The Night Shifts
One of the most important tasks as volunteers was the night shift, which involves monitoring particular nests which were due to hatch soon and ensuring any hatched turtles make it to the sea safely rather than going towards light pollution. Normally, in the night when the eggs hatch, the largest source of light is the moon over the sea. Moonlight serves as a guide for hatchlings. However, many beaches are becoming tourist attractions and opening bars, hotels, and other sources of light pollution.
To address the issue of light pollution,volunteers, including myself, set up arenas around nests so that hatchlings would be captured until we awoke. When we found hatchlings, a 12m trench was dug away from light pollution for the hatchlings to crawl to the sea in. This is the distance required for the female turtles to make their imprint on the beach and return to lay their own eggs.
A fact which many people, including myself before my experience in Kefalonia, do not know, is that mass hatchings (>20 from one nest) are not normal. 1-5 hatchlings are a normal amount from one nest. We had a few mass hatches during my time in Kefalonia, and with roughly 100 eggs per nest, hatchings could easily be trapped underneath the weight of 20+ other hatchlings pushing down. After a mass hatching, an excavation was done, often resulting in the recovery of many trapped hatchlings. It was times like these when I realized how critical the work of Wildlife Sense is. Without the monitoring and excavation, those hatchlings found would have cooked in the sand and died before being given a chance to repopulate the endangered species.
Disruptions to the Life Cycle
Sadly, the natural life cycle of sea turtles lends itself to be largely impacted by anthropogenic climate change and behavior. With survival rates being an abysmal 1 in 1000, even without anthropogenic impacts, survival is unlikely. Secondly, only reaching sexual maturity at 15 years means their sex cannot be identified until this time, making conservation efforts difficult. Due to the long maturation period, there are many obstacles such as entanglement in fishing nets, boat strikes, plastic pollution, and many more which can easily kill turtles before they have had a chance to mate. This has a detrimental effect on the population size over time. Before humans became a problem, sea turtles lived for up to 60 years, but now, humans have cut their lifespan in half.
There are many individual changes that make a huge difference to save sea turtles. The choices we all make in our everyday lives have a large effect on the world. As consumers, we must be aware and conscious. For example, plastic straws and bags are incredibly dangerous to sea turtles. Straws can get lodged in their mouth or nose, and bags are easily mistaken for jellyfish which make up a part of their diets. Ingesting plastic blocks their digestive system, killing the helpless turtles.
An even larger problem is entanglement in fishing nets, which causes drowning. “Ghost nets” are left the sea because fishermen have no regard for the problems their old nets can cause to marine life. Reducing your fish intake damages fishing industries which overly exploit fish populations worldwide. Not only will this positively affect marine ecosystems, but it will also reduce the demand for fishing. Therefore, the number of “ghost nets” will decrease.
Lastly, education is absolutely critical. After asking many of my friends and family members to read this article, many had no idea about sea turtle diets, how light pollution can kill hatchlings, and how global warming affects them. How can we expect people to act on things they do not know about? Education about conservation must be implemented, otherwise, there is no hope for the protection of the species. So, what can you do? Educate others about sea turtles, volunteer for a conservation charity, donate to such charities, write to supermarkets and tell them to reduce their single-use plastic consumption, and spread the word as much as possible. Sea turtles desperately need us to change our lifestyles. If we make the right changes, we could possibly save these amazing marine reptiles.