10 Facts about Marine Turtles

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turtle hatchling crawls down beach
© Jonathan Caramanus /Green Renaissance/ WWF-UK
Fascinating Facts

Marine turtles have been around for more than 100 million years ago. They lived alongside the dinosaurs. 

Here are some things you might not know about them.
 

1. Locals

Although they breed in the tropics and subtropics, 5 of the 7 recognised species of turtle are found in New Zealand waters. Green and Leatherback turtles are the most common.

2. Cold water 

Leatherback turtles prefer oceanic waters and can tolerate much colder temperatures than other turtle species. They are widely spread around New Zealand and have been recorded as far south as Fiordland but favour foraging grounds around Northland. 

3. It's about the shell

Leatherback turtles are named for their shell, which is leather-like rather than hard shell like other turtles. They are the largest sea turtle species. 

4. Change of diet

Adult green turtles are herbivorous, the only turtle species that are. Their hatchlings, however, are omnivorous eating a range of animals including jellyfish and fish eggs. As they grow they include seaweed and plants into their diet until they become entirely reliant on them.

5. It's not about the shell

Green turtles are named for the greenish colour of their cartilage and fat, not their shells.

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close up of turtle
© Juergen Freund / WWF-Canon

Green turtle

6. Return home

Once mature male turtles never leave the sea but females come ashore to lay eggs – typically on the same beach where they originally hatched.

7. Too hot for some

Turtles have temperature-dependent sex determination. The temperature of the sand their eggs incubate in determines if the hatchlings will be male (low) or female (high). This means that rising temperatures due to climate change can skew sex ratios. 

8. Threatened

Six out of 7 marine turtle species in the world are threatened with extinction. With the 7th, the flatback, being 'data deficient' - there's not enough information to know how at risk they are. Turtles face many threats.

9. Illegal wildlife trade

Despite a global ban by the Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES) since 1977, the unsustainable take and illegal trade of turtles, turtle eggs, meat, and their parts persists. Asia Pacific is at the epicentre of use and trade in marine turtles.

10. Bycatch

Getting accidentally caught in fishing gear is another big threat to marine turtles. Hundreds of endangered sea turtles have been caught in New Zealand’s commercial fisheries since 2002, yet there are currently no mandatory mitigation measures to prevent the bycatch of turtles in our waters.