Turtles; Kemp’s ridley

I am intrigued by the magical appearance of turtles. I try to learn more about their biology, the different types of turtles and the threats they face. On Nurtured by Nature I will share 7 posts about turtles, each post containing general and turtle-specific insights. This time the Kemp’s Ridley turtle!

See my previous post on the Loggerhead turtle here.

General – Shell and identification 

Turtle species are often confused.  Seven different species of turtle swim in our oceans, but all look like turtles, right? As opposed to some other reptiles, sea turtles are actually quite easy to identify. You just have to know what to look for.

Every sort of turtle has a different shell. The upper shell is called a carapace and is made of bone. Turtles also have a shell on their belly, called a plastron. In the carapace, the spine and some ribs of the turtle are fused with dermal plates (bony shields). This means the turtle will never be able to get out of its shell – it is part of its body. The outside of the shell is covered in scutes, which are plates made of keratin. That is the same keratin which your hair is made of.

You may recall from pictures on the internet (or your own dives!) that the shell is composed of multiple geometric shapes. Those are the scutes. The number and placement of these scutes are specific for each turtle species and can, therefore, help us with identification.

The first distinction can be made between turtles with a hard carapace and turtles with a leathery shell. The story you are reading does not apply to those Leatherback turtles.

In the picture below I have drawn the shells (carapace) of six different turtle species. It is quite difficult to draw it the right way and I felt like I shouldn’t go on by including flippers and probably ruining this masterpiece in the end 🙂 Anyways, identification is based on:

  1. Touching of the scutes with the scute closest to the turtles head, which you can see in orange
  2. The number of scutes on either (symmetrical) side of the shell. See yellow.
  3. The shape of the shell. Circular or not. And in the case of the Flatback & Green turtle; flat or not.
  4. The number of scutes between the eyes. This is not very clear, but I tried to draw it in green on their heads.
Identification based on shells. Drawn by myself, adapted from seaturtle.org

Lepidochelys kempii

Kemp’s Ridley is named after Richard Kemp, who discovered the species. It is the rarest turtle in our seas. IUCN* has classified this species as critically endangered, but very little data on distribution and threats is available. The Kemp’s is home to the warmer waters of North America and is therefore sometimes referred to as the Atlantic Ridley. The turtles migrate but come back to the same beach each year to lay their eggs. The large aggregations of female turtles at nesting sites are called arribadas (in Spanish).

Kemp’s Ridley Arribadas. Source: Sea turtle 911

Kemp’s is very vulnerable to capture in nearshore fishing gear, like shrimp trawlers. The fact that they live mostly in the Gulf of Mexico, makes that the entire population was largely affected by the Deepwater Horizon oil spill in 2010. Conservation efforts by organisations like WWF, the National Wildlife Federation, and NOAA include:

  • Nesting ground protection on beaches. Providing safe nesting ground without human interference (e.g. making it a tourist attraction or stealing the eggs), ensures the return of the turtles and better hatchling chances.
  • Fisheries management. Installing and enforcing laws against certain fishing methods can prevent turtles to become bycatch victims. (Also see my previous blog on fisheries restrictions.)
  • Estuary and wetland restoration improves habitat for Blue crabs, which in turn make one of the favourite food sources of the Kempii.
  • Beach cleanups contribute to less plastic in the oceans. Kemp’s, like most turtles, have a hard time distinguishing a floating (plastic) bag from a delicious jellyfish meal.

Kempii like jellyfish and crabs for dinner, but also fish, seaweed, and molluscs. Kemp’s is the smallest of all sea turtles and can weight up to 50 kg at maturity. They are born with an almost grey-purple looking carapace but with age, it fades to green (see below).

Sources

3 thoughts on “Turtles; Kemp’s ridley

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s