Researcher: Dr.Keith LeggetRegion: Maputaland, South Africa
BackgroundSituated along the extreme north-east coastline of South Africa in the Maputaland Coastal Forest Reserve, the Rocktail Bay area hosts an annual spectacle that has remained unchanged for thousands of years. Every summer, hundreds of Leatherback and Loggerhead turtles complete their breeding cycle and emerge from the Indian Ocean to lay their eggs on this stretch of coastline – incredibly most returning to the exact beach on which they themselves hatched! However, turtle numbers seemed to be dwindling, possibly due to over-exploitation of sea turtle products, so in 1963, scientists from the then-Natal Parks Board (now Ezemvelo KZN Wildlife) under the direction of Dr George Hughes initiated a project to monitor the number of nesting females per season, and to protect the beaches on which they nest from further disturbance.
In 1971, the project was expanded to include collecting data on Loggerhead hatchlings. Between January and April, hundreds hatch from the nests and make their way down to the sea. By ‘notching’ their shells at this time and ‘reading’ the notches when they return to nest, the age at which they reach sexual maturity can be calculated. (This is impossible with Leatherbacks as their carapaces are made of unsegmented living tissue.) In 1997, the new technology of satellite tracking systems was implemented to determine the migratory routes of both species after nesting.
Ironically, results of this study show that both turtle populations are in fact increasing – the only populations in the world known to be doing so!
In 1998, funding from Ezemvelo KZN Wildlife dwindled significantly, and finances had to be found elsewhere. Donations from the World Wildlife Fund, the Wilderness Safaris Wildlife Trust and Rocktail Bay Lodge contributed vital funds, amounting to R150 000 annually. Rocktail Bay Lodge therefore fulfils two functions: Wilderness guides share nightly patrols and monitoring the turtle populations with Ezemvelo KZN Wildlife, and the guests that accompany them are treated to an awe-inspiring sight that often results in guests donating funds and ‘adopting’ turtles.
MethodologyTwo methods are used in the project: Daily patrols and data collection.
Patrols are conducted at night when the turtles emerge from the sea to nest and also at low tide so as to minimise sand disturbance of the beach and in order to stay well clear of the high tide mark, above which the turtles lay their eggs. During the nesting season, in all weathers, trained Ezemvelo KZN Wildlife and Rocktail Bay/Wilderness Safaris staffs spend every night patrolling and monitoring their beloved turtles. The patrol vehicle from Rocktail Bay is often loaded with lodge guests, allowing them a once-in-a-lifetime chance to experience one of Nature’s most awesome events. This type of controlled ecotourism in the research area is vital in order to generate awareness and funding for the Project.
Patrol vehicles drive at low speed along the beach searching for turtle tracks. Once these are found, the vehicle is stopped and the tracks are followed on foot to where the turtle is laying her eggs. First, it is noted at what stage of the process she is, then she is tagged and a microchip is injected. (This is done only when the female is actually releasing the eggs from her ovipositor as it is believed that they enter into a trance during this phase, allowing minimal disturbance to the turtle.) Data such as species, date and time, GPS coordinates of the nesting site, length and breadth are all recorded.
Notching of Loggerhead hatchlings takes place as the little creatures emerge from their nests and before they reach the sea. A ‘notching tool’ is used, and a different sequence of outer shell segments is used per year; in this way, when an adult notched female is located, one can determine her exact age. Additional data is recorded: number of hatchlings per nest, date and GPS location of each one.
UpdateA special thanks to the two locally trained guides Gugulethu Mathenjwa and Mbongeni Myeni for their unsurpassed commitment and enthusiasm shown throughout the seasons. Leza Morton, Andrew Temblett and Shannon Maclean are thanked for their dedication shown to raising funds for the Maputaland Sea Turtle Project at Rocktail Bay Lodge. And thanks to George Hughes who has been the driving force behind the project for so many years.
It has been the greatest privilege of my life over the last four years to be part of Wilderness Safaris, an organisation that has committed itself to conserving Leatherback and Loggerhead Turtles along the Maputaland coastline. A very special thank you must go to all the guests from Rocktail Bay Lodge that contributed so generously towards the turtle research project, because without them this programme would not be possible.
Findings of 2008/2009 Season
Successful loggerhead egg-laying this season totalled 212 loggerhead nests and 49 leatherback nests successfully laid. 135 loggerhead females chose to come up the beach but did not lay and the same happened on five occasions with leatherbacks.
Between October and March over the past season, and during the nightly four-hour window period, 88 Loggerhead Turtles and 171 Leatherback Turtles were recorded nesting along the southern research area. The number of nesting Loggerhead Turtles has therefore continued to increase from previous years, while Leatherback Turtle numbers have fluctuated over time – but this is considered normal and part of the natural cycle.
In terms of losses, one Loggerhead was killed by humans and a very small number of nests were dug up and the eggs were removed. One Leatherback washed up dead, cause of death unknown, and a small percentage of rear limbs in Loggerhead Turtles showed evidence of shark bites. Losses of eggs and hatchlings of both species were attributed to a variety of predators: water mongoose, large-spotted genet, water monitor, ghost crabs and honey badger.
A large percentage of nested turtles in both species were not located and therefore not identified. This is because of the restrictions imposed by the tides, since access to the beach is only possible two hours on either side of low tide – so only a third of a night can be surveyed. The other problem is that when guests accompany guides, while this is vital for educational purposes, they tend to spend more time watching the first couple of nesting turtles, so that there is less time to watch all the others on the beach – resulting in fewer being identified before they head back to see. . A possible solution for the future would be to utilise two vehicles, one purely for patrolling and one reserved for guests; this might add to the guest experience as well.
Thanks to the length of time this project has been running (1963-present, making it the longest ongoing scientific study of turtles in the world) a large amount of other data and have been collected. For example, Leatherback Turtles seem to prefer nesting at neap tide, while Loggerheads showed no obvious partiality.