LOGGERHEAD AND LEATHERBACK TURTLE
Seven species of marine turtles exist in the world’s oceans today, all of them have unique lifestyles in that they travel great distances and take decades to mature. This makes turtles important indicators of ocean health. There are five species found off the Kwa-Zulu Natal Coast, namely, the loggerhead, leatherback, hawksbill, green and Olive Ridley turtles. Of these five species that occur in South African waters, only the loggerhead and leatherback females nest along our shores.
Both loggerhead and leatherback turtles nest during the summer months at night (October – March). They use medium to coarse grained sandy beaches that are backed by high dunes with well developed primary vegetated dunes. Steep beach faces makes it easy for loggerheads to swim through the surf over low lying rock ledges. The females emerge from the surf and rest in the wash zone on the beach. It is here when they assess the beach for any danger by lifting their heads and scanning the beach. Satisified that there is no danger they then proceed up the beach to well above the high water mark.
Having found a suitable site at the vegetation edge the females commences by excavating a body pit with her fore flippers, this enables her to lie with the top of her carapace level with the beach. She then digs an egg cavity with her hind flippers. The egg pit is a flask shaped hole about 50-80 centimetres deep. A normal clutch constitutes 100-120 soft white shelled eggs which are deposited into this hole. When all of the eggs have been laid the female fills the hole with sand and kneads and presses the surface until the sand is packed hard. Once this is done she disguises the nest site by throwing sand with her fore flippers over the nesting area. Satisfied that her nest is safe she returns to the sea.
Leatherbacks can return up to seven times to lay eggs, while Loggerheads return up to four times in a single season.
Both loggerhead and leatherback turtle eggs take between 55-64 days to mature. Once ready to emerge the hatchlings cut their way out of the egg with a special egg tooth on the end of their beaks. After the bulk of the eggs have hatched the hatchlings start digging at the sides of the nest.
THREATS TO TURTLES
Turtles utilize both coastal areas and the high seas, where humans activity is increasing, therefore no area is sacred or safe for them. They are under extreme pressure because of bad coastal zone practices and habitat destruction, direct harvesting for food and curious and are caught as by catch in local fisheries.
THE MOST SERIOUS THREATS ARE PRESENT AT VARIOUS LIFE STAGES
1. Nesting – Egg collecting, slaughtering for meat, coastal development, sand mining & beach driving.
2. Home Ranges – (coral reefs, sea grass beds, open oceans) These are disturbed or destroyed by bad fishery practices, pollution and global warming.
3. Migrational Movements – During migrants they are threatened with being caught in trawl or drift nets and long lines.
MONITORING TURTLES FOR 40 YEARS
The project began in 1963. In 1916, all harvesting of sea turtles was banned in South Africa, and from the early 1960’s, concerted efforts were made to enforce legislation banning egg collection and the harvesting of adults. This was aided by effective continuous and high-intensity monitoring. In 1963, under the auspices of the Natal Parks Board, a Turtle Conservation and Monitoring programme was initiated along the north- eastern coast of Kwa- Zulu natal which is now the Greater St Lucia Wetland Park. This programme, currently under the supervision of Ezemvelo KwaZulu Natal (EKZN) Wildlife, is still in existence todat. It is one of the longest, continuous loggerhead/leatherback turtle monitoring programmes in the world.
THE PURPOSE OF THE PROJECT
To monitor and record nesting populations of loggerhead and leatherback sea turtles along the eastern seaboard and simultaneously provide protection of the females during this vulnerable stage on the shore. Furthermore to establish an annual population census and determine distribution of nesting loggerhead and leatherback sea turtles in South Africa and Southern Mozambique.
The 56 kilometer of beach, north and south of Bhanga Nek, in the Greater St Lucia Wetland Park, is the main focus area of the project. During the peak nesting season (mid- October to mid – March) intensive patrols are conducted by students, field rangers and temporary staff for the entire 56 kilometres. About 20 km of this stretch of beach is patrolled throughout the year.
More erratic and less intensive monitoring is also undertaken south of Mabibi and Cape Vidal as well as in Southern Mozambique north of Ponte Malongane.
Sixteen local community members have been trained as monitors and are employed over the nesting period (October – March) to gather valuable data.
ACHIEVEMENTS OF THE PROGRAMME
1.The ongoing monitoring and conservation efforts have had a positive effect on population size. Since the programme’s inception, a total of 46, 893 loggerhead and 11,509 leatherback females have nested on the beaches of The Greater St Lucia Wetland Park.
2.Scientific information has been obtained about the nesting and non-nesting distribution range.
3.The role of Agulhas current in distribution of hatchlings has been established.
4.The conservation effort contributed to the establishment of Marine Protected Areas
5.Management actions are in line with international conventions.
6.International recognition and collaboration were obtained for both research and management of the breeding populations of turtles and provided guidelines for conservation activities in the South Western Indian Oceans.
7.The programme served to increase public awareness and create tourism benefits along the Park’s beaches.
Posted on Flickr by Jeroen Looyé on 2012-02-24 18:18:12