Species of the week

Meet one of the 5 species of sea turtles that occur in Mozambique.

Scientific name: Chelonia mydas
Common name: Green turtle, Pacific Green -turtle
Class: Reptilia
Order: Testudinata
Diet: They are primarily herbivores, feeding on several species of seagrass
Average lifetime: can live up to 80 years
Size: 90 to 120cm
Weight: up to 250kg
IUCN category: Endangered

The green turtle is one of the five species of sea turtles that occur in Mozambique and is the only species of the genus Chelonia. When juveniles, they have a brown color and a greenish gray color as adults, four pairs of side shields with a shell in oval shape.

Green-turtle-ventral-view

Social organization
They are solitary individuals, but is possible to occur some grouping in migration times for breeding or foraging for food.

Reproduction
They reach sexual maturity between 20 and 50 years. They migrate up to breeding sites, and females look for a mate every three to four years, while males every year visit the breeding areas in an attempt to mate. After mating, the females go up the beach at night to nest, dig the hole in the area with the fins and lay the eggs (100-200); they cover it and return to the sea. It is possible that in each nesting season they make 4-6 nests. The eggs are 4.5 cm in diameter, and take about 50 to 70 days until hatch, and the youngs instinctively follow up to the sea.
It is estimated that only 1% of these babies reaches sexual maturity.

Green-turtle-hatchlings

Ecology
Green turtles are the only exclusively herbivorous sea turtle. In the juvenile stage are omnivores, but when they reach the adult stage, they feed on algae and seagrasses. They are highly migratory species migrating between feeding and nesting areas, and they occur around different types of habitats depending on their stage of life.
Mature individuals spend most of their time in shallow coastal waters with lush beds of seagrass, and adults are often in coastal bays, lagoons and seagrass shoals.
Generally, live on islands and bays which are protected and are rarely sighted at sea. They are predated only by humans and sharks when adults. In juvenile phase, they have a higher number of predators, including crabs, small marine mammals and seabirds.
It is believed that the juveniles spend most of the time on the open sea.

Distribution
They have a global distribution, occurring in more than 80 countries, including Mozambique.
The largest population of sea turtles is the Great Barrier Reef in Australia and the Caribbean Islands.
Threats: Habitat destruction, coastal erosion, tourism, fishing (drag, drag to the beach, using longline, artisanal fisheries ) , the harvest of eggs for food, and the traditional use .

Conservation measures
It is important to make the conservation of nesting and feeding sites. The prohibition of hunting and supervision are measures that can reduce mortality of turtles. Sensitization of communities to change certain habits (consumption of meat and eggs) and their inclusion in the conservation of this resource, are essential.

Curiosities

  • It’s called green turtle , because of the color beneath their carapace.
  • In Mozambique is the most common species, being distributed throughout the coast, with the highest incidence in the following locations: Bazaruto Archipelago for feeding and growth, Peninsula of San Sebastian for nesting, between the Peninsula Quewene and Quirimbas Archipelago, Bazaruto Archipelago and Primeiras and Segundas islands.

Sources
  • IUCN
  • Wikipedia
  • Louro et al., 2006. The Conservation Status of Marine Turtles in Mozambique. Report submitted to MICOA, Maputo. 45 pp.
  • tamar.org
Pictures