Green turtleChelonia mydas

Category
  • Seagrass
Tags
  • Green turtle
  • Sea turtle
  • Reptile

Description

The Green turtle is a reptile from the family of Cheloniidae. It is one of the largest, most common species of marine turtles. It has a smooth oval greenish brown to dark brown carapace with thin plates that do not overlap, with grey and black patterns. The under shell is a pale yellow or orange colour. Green turtles have a pair of scales in the nasal area and a bottom serrated jaw, with no teeth. Each rare flipper has a single visible claw[1]. The front flippers of adults has one claw while juveniles have two. Females are usually bigger than males. The Green turtle can grow up to 140 cm in length and weigh between 120 - 280 kg.

 

[1] ‘FAO Fisheries & Aquaculture - Species Fact Sheets - Chelonia Mydas (Linnaeus, 1758)’.

Habitat and ecology

This species is present across many latitudes around the world,  mostly in tropical regions and at times in subtropical waters. It is found across parts of the Atlantic, Indian and Pacific Oceans and Mediterranean Sea and nests in over 80 countries worldwide. Both male and female individuals migrate, and they may cross oceanic zones that spread over thousands of kilometers. When adults are not breeding, they cohabitate in coastal feeding grounds with larger juveniles. The diet of the Green turtle consists of seagrass and algae[1].

When sexual maturity is attained, Green turtles migrate between their breeding and foraging grounds. Courtship is instigated by the males and copulation occurs at the beginning of the breeding season and stops right before nesting. The breeding cycle is usually every two years, but this may extend to 3 or 4 years. Females return to the same nesting site to lay their eggs. There is a two-week interval between successive nesting in the same season. Green turtles can lay a 100 to 200 eggs at each nesting. Hatchlings begin an oceanic phase after they leave the nest, floating in the open ocean. A few years later, juvenile turtles settle in shallow coastal habitats, usually rich in seagrass or algae on which they feed until they mature.

 

Conservation and management

According to the IUCN Red list, the Green turtle is an ‘endangered’ species[2]. The population trend of this species is declining globally. Threats include fishing and being trapped as bycatch. Other threats are overexploitation of eggs, nesting females, individuals in foraging sites and mortality related to coastal development that inevitably destroys nesting sites. In addition, changing thermal profiles and sand erosion decrease the quality of nesting sites available to females and bring about behavioural changes in hatchlings.

The collect of Green turtles is legal in several countries despite its endangered status. This species is managed in part of its range. It is listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora); Appendices I and II of CMS (Convention on Migratory Species) and various other management plans.

 

 


[1] ‘Green Turtle | WWF’.

[2] Seminoff, ‘The IUCN Red List of Threatened Species’.

Did you know?

Tiger sharks are one of the main predators of the Green Sea Turtle.

Green turtles attain maturity between 20 to 50 years old[1].

They can live up to 100 years old[2].

 


[1] ‘10 Fun Facts About Hawaiian Green Sea Turtles’.

[2] ‘Green Sea Turtles’.