What has science in common with seaturtles?

1. Abstract

Two years ago I had the chance to volunteer for 10 days with the Juara Turtle Project (JTP) on Tioman Island, Malaysia. JTP focus on creating a sustainable relationship between people and the natural environment. JTP encourages law enforcement for environment protection and to secure safe and natural nesting beaches for turtles. Volunteers are given a chance to learn about endangered sea turtles and to better understand the part humans have to take in this situation and to gain practical experience in this field.

2. Sea turtles are protected species

All sea turtles are either considered vulnerable, endangered, critically endangered or data deficient by IUCN (International Union for Conservation of Nature). Most of them are feared to become extinct in the years to come, if no action to protect them is taken. The available information about the numbers of remaining sea turtles differ very much from source to source. But it is understood that actually they appear to be rather in the very low thousands per species than in the millions, as it should be. Sea turtles reach reproduction at about 30 years of age. In today’s environmental situation only a very few will survive up to this age. Most of the young turtles are eaten by natural predators. This alone is natural and has never endangered the species as such. The reason that sea turtles are endangered is because of the human expansion. Without sustainable help and re-thinking of the human way of life, they all will go extinct in the next 20 to 50 years.

3. Basic knowledge about sea turtles

a) The life cycle

blabla

Picture: Sea turtles follow a life cycle as indicated and described in the graphic below. The active part of life starts with the hatching, after seven to eight weeks in the nest. In nature, for many of them life ends soon after by being eaten while crawling from the nest to the sea. But some of them may reach even 120 years or more and therefore they can contribute to the continuation of the species.

b) How gender gets defined

The gender of sea turtles, as well as of other species like crocodiles and lizards, depends on the temperature in the nest during the middle third of the hatching period. While the average temperature in a nest is 30 degrees, 29 degrees will generate male and 31 degrees will generate female. Towards the centre of the nest the temperature might be slightly higher than at the periphery. This allows male and female to develop in the same nest. Enough oxygen can reach the hatchlings through the sand and the egg’s shell.

c) Millions of years of development

The first reptiles arose about 300 million years ago. The oldest sea turtle fossil, the Proganochelys, dates back to the Triassic period, some 220 Mio. years ago. It’s immediate ancestors are not known and there is no known transitional animal between reptiles and sea turtles. It is reported that from Jurassic (200 Mio. years) to Cretaceous (145 Mio years) the bodies of sea turtles changed from ugly looking, horned animals to rather something looking like freshwater turtles. Modern sea Turtles arose in the early Cretaceous time (110 Mio years ago).

skeleton.jpg

Picture: A fossil of the Santanachelys gaffneyi turtle  was found in 1998 in Brazil.

heretage

Picture: Present day sea turtles are considered “modern sea turtles”. They belong either to the Cheloniidae family with four species or to the Dermochelyidae family with one species. The Toxochelyidae and the Protostegidae families are considered extinct.

4. Nesting beaches on Tioman Island

a) Mentawak beach

Munchure beach.jpg  Picture: Mentawak beach (own photo)

This is the largest beach and most important beach for JTP. About 6 Green and 3 Hawksbill visit this place for nesting. The beach is about 1km long, with few rocks, and it hosts the headquarter of the JTP project. The nesting season for Hawksbill is January to June and for Greens is from May to September.

b) Penut beach

This is a very small beach of about 100 meters length. Only 2 to 3 Hawksbill turtles lay eggs there in spring and early summer time.

c)  Munjur beach

This is a small beach. 5 to 6 Green and 1 Hawksbill visit this beach to lay eggs.

5. Overview of the nesting Season 2014, until August

a) Some statistics

Season 2014

Graph: This graph shows the nests from January till August. The nesting season started in January with 1 Hawksbill nest on Mentawak and came to a maximum in July with 1 Hawksbill on Penut beach, 3 Green on Mentawak beach and 10 on Munjur beach.

b) Laying the eggs in the sand and say “bye bye” to the offspring.

eggs   Picture: Laying its eggs (own photo)

  Hatchlings

       Picture: 30 days later, bye bye (own photo)

c) My best estimation is that 100 eggs develop as follows:

Hatched eggs

85

Delayed hatchlings

3

Dead hatchlings

1

Boiled eggs (egg’s white part turns opague)

4

Eggs with worms in it

4

Not fertilized eggs

3

 

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