Happy World Sea Turtle Day!

Sea turtle swimming in the ocean.
Photo by Giorgia Doglioni on Unsplash

World Sea Turtle Day is a day to honor and highlight the importance of sea turtles. It is on June 16th because that was the birthdate of Dr. Archie Carr, the Sea Turtle Conservancy’s founder and the ‘father of sea turtle biology.’

Sea turtles have been around for over 100 million years, as far back as the Cretaceous period and the dinosaurs. They spend their lives in the sea, except for nesting, and swim in almost all oceans. Sea turtles navigate through their sensitivity to the Earth’s magnetic fields. All species of female sea turtles return to the same exact beach they hatched on to nest.

Leatherback sea turtle hatchling
“A leatherback sea turtle hatchling starts and begins its adventure into the vast unknown, to grow, to see the world, and to become its adult self.” Photo by Max Gotts on Unsplash

Endangered

Six out of seven species of sea turtles are threatened with extinction, according to the IUCN Red List. The 7th is listed as ‘data deficient.’

“Humans have caused sea turtle populations to decline
significantly all over the world.” -Oceana.org

Green sea turtle
Photo by David Clode on Unsplash

Importance

“Sea turtles are a fundamental link in marine ecosystems.” -World Wildlife Fund

Sea turtles keep the natural ocean environment and the food chain balanced. Following are specific ways in which they provide this balance.

Balancing the Food Chain

The largest sea turtles, the leatherbacks, consume up to 440 pounds of jellyfish daily. Loggerheads and Green sea turtles also eat them. As sea turtle populations decline, jellyfish populations increase. This not only affects humans, but it affects fish populations. “Declining fish stocks leave jellyfish with less competition for food, resulting in proliferation of jellyfish around the world. The increase in jellyfish is already proving detrimental to the recovery of fish stocks since jellyfish prey on fish eggs and larvae.”

Certain fish “clean” the barnacles, algae, and epibionts (organisms that survive by living on other organisms) from sea turtles’ bodies and shells, sometimes providing their sole food source. Without turtles, these organisms would have to find another, potentially unsuccessful, food source. “Species associated with a host, such as sea turtles, are important to generating and maintaining diversity throughout the world’s oceans.”

Sea turtles also provide food to many other species as prey. Many predators eat eggs and hatchlings, and even juvenile sea turtles. Sharks and killer whales sometimes eat adult sea turtles.

Last, but not least, some species, such as loggerheads, consume crustaceans. While eating they break the shells into fragments and create trails in sediment along the ocean floor, practices that both contribute to what is known as ‘nutrient cycling.’

Green Sea Turtle grazing seagrass at Akumal bay.
“Green Sea Turtle grazing seagrass at Akumal bay.” Photo by P.Lindgren on Wikimedia, Creative Commons license (CC BY-SA 3.0)

Seagrass control

Sea turtles are one of the few animals that eat seagrass, especially Green sea turtles. It needs to be cut short constantly to stay healthy and to keep growing. Seagrass beds are important because they are the breeding and developmental grounds for many species of fish, shellfish, and crustaceans. Those species are consumed by many other species, so lower levels of seagrass impact the food chain, all the way up to humans.

Additionally, seagrass control provides balance to the ocean. “Without constant grazing, seagrass beds become overgrown and obstruct currents, shade the bottom, begin to decompose and provide suitable habitat for the growth of slime molds. Older portions of seagrass beds tend to be overgrown with microorganisms, algae, invertebrates and fungi.” The Caribbean has seen a sharp decrease in Green sea turtles and thus a loss of productivity in commercially fished species.

“All parts of an ecosystem are important, if you lose one, the rest will eventually follow.” -Sea Turtle Conservancy

Dune Protection and Prevention of Beach Erosion

Beaches and dunes do not get a lot of nutrients because sand doesn’t hold them. However, all of the sea turtle nests, eggs, and hatchlings don’t make it to the sea, leaving valuable nutrients behind, such as nitrogen, phosphorus, and potassium, that allow the dunes to thrive. Even the eggshells from hatched eggs provide some nutrients. This is called nutrient cycling. “Dune vegetation is able to grow and become stronger with the presence of nutrients from turtle eggs. As the dune vegetation grows stronger and healthier, the health of the entire beach/dune ecosystem becomes better. Stronger vegetation and root systems helps to hold the sand in the dunes and helps protect the beach from erosion.” But as sea turtles decline, nests decline, and the beaches start eroding.

Additionally, sea turtle eggs, shells, and even hatchlings provide food for other species, which then redistribute the nutrients through their feces. Those nutrients also feed the vegetation that provides stabilization to the dunes.

Sea turtle swimming in the ocean.
Photo by Baptiste RIFFARD on Unsplash

Coral Reef Development

Hawksbill Sea Turtles, which eat a lot of sea sponges, help protect the coral reefs. “Sponges compete aggressively for space with reef-building corals. By removing sponges from reefs, hawksbills allow other species, such as coral, to colonize and grow.” Without sea turtles, sponges could start to dominate reef communities and limit the growth of corals, and altering the entire coral ecosystem.

“These amazing creatures are endangered by human interactions, both intentional and unintentional: fishing lines, nets, boat hulls, propellers, and plastic debris, which the turtles mistake for jellyfish and ingest.” -Joel Sartore

Sea turtle entangled in abandoned fishing netting.
Entangled green sea turtle. Photo by NOAA Marine Debris Program on Flickr, Creative Commons license (CC BY 2.0)

What You Can Do

There are so many things you can do to help protect sea turtles! Here’s a quick list, but you can check out my article “Sea Turtles are Endangered” for detailed information.

      • Avoid plastic bags. This is a big one because turtles, especially leatherbacks, mistake floating plastic shopping bags for jellyfish, and ingesting bags kills them.
      • Stop using disposable plastic straws; decline them at restaurants. If you really must have one, carry a metal or glass straw with you.
      • Keep beaches clean. Litter on beaches prevents hatchlings from reaching the sea.
      • Turn off the lights.
      • Use coral reef-friendly sunscreen.
      • Buy sustainable seafood.
      • Do your part to slow climate change.
      • Reduce the chemicals you use in your yard and dispose of others properly through the hazardous waste collection in your area.
      • Don’t buy products made from real turtle shells.
      • Make turtle cookies. I know that sounds funny, but if you have children, cookies are a great conversation starter. Even coworkers would give you a few minutes of listening while enjoying them.
      • Educate others. Try the cookie trick.
      • Stop releasing helium balloons.
      • Recycle, or better yet, don’t buy plastic as much as possible.
Plastic bag floating in ocean, looking similar to a jellyfish.
Photo by MichaelisScientists on Wikimedia, Creative Commons license (CC BY-SA 4.0)

Adopt-A-Turtle!

There are numerous programs that offer sea turtle nest “adoption” for donation. You can do a quick internet search to find one. I adopt a loggerhead sea turtle nest annually through the Coastal Discovery Museum on Hilton Head Island. For my donation, I receive a certificate, a car sticker, and regular email updates about the general nesting season, and information about the specific nest I’ve sponsored. The funds support their educational programs “which inspire people to care for the Lowcountry and all the plants, animals, and people who call this place home.”

Taped off with sign posted, Loggerhead sea turtle nest on the beach.
A loggerhead sea turtle nest on the beach on Hilton Head Island, May 2021. Photo by me

I hope this information was helpful, and thanks for reading. Please share and subscribe!

 

Additional Resources:

Article, “Information About Sea Turtles: Species of the World,”

Article, “World Sea Turtle Day: 10 Things you Never Knew About Sea Turtles,” World Wildlife Fund UK, June 16, 2018. This is a quick read and is a great way to introduce the topic to children.

Article, “Drone footage shows 64,000 green turtles migrating to Cairns rookery,” The Sydney Morning Herald, June 10, 2020. The article shows a migration map for Green Sea Turtles.

Article, “Information About Sea Turtles: Threats to Sea Turtles,”

Footnotes: