Throughout the recent break (4/7/16 – 11/7/16) I had the unique opportunity to experience the (very sandy!) life of threatened flatback (Natator depressa) and olive ridley (Lepidochelys olivacae) turtles. I assisted in data recording of both species (though primarily flatbacks) as they nested and started new lives along the shores of Bare Sand Island, one of a small chain of islands, about 50km off the coast of Darwin. Green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) turtles also forage in the area, though focus now occurs primarily on recording nesting populations, so I did not interact with these guys. Over an amazing week long period, I assisted in the daily routines of locating, measuring and recording tags of adult female flatbacks past the hours of high tide (tidal range on the island restricts the nesting periods to approximately 2 hours following high tide).
Mornings then involved the fascinating task of following nestling tracks to locate hatched nests. We then dug up these nests to record hatching success, through the number of shells, extended tracks and occasionally (if we were lucky) live hatchlings in the nests! We also had the nitty gritty (often very smelly) task of opening unhatched eggs to determine whether eggs were depredated, embryos or undeveloped. Eggs unhatched after initial hatches are very unlikely to be successful so this did not interfere with development.
This routine helps to document the overall success of laying turtles and of different nesting locations. Any live hatchlings were then taken back to camp for short periods to show to visiting tourists in the evenings, and occasionally to take individual hatchling data recordings, if found in sufficient numbers.
Hatchlings are then released to the ocean and begin their long perilous journey for survival. Sadly, the average hatchling has between 1 in 1000 or 1 in 10 000 chance of survival (largely due to natural predation from both land dwellers (such as; birds, crabs, goannas) and sea dwellers (such as fish, sharks and sea birds). Still we tried our best to send them happily on their way (can only hope)!
But why conduct this research?
Australian waters represent one of the most important havens for marine turtles in the world, particularly for nesting in the Indo-Pacific region. Over these areas contain 6 of the only 7 marine turtle species globally. Unfortunately, each of these species are listed as either vulnerable or endangered on the IUCN Red list, due to a long history of human-induced decline thanks to factors such as; pollution, overharvesting, accidental captures, disease, marine debris and, of course, the destruction of critical habitat.
These issues (along with predation) continue to threaten populations globally and Austurtle works to combat further decline by continuing to monitor population size and abundance of nesting turtles in addition to determining any threats to survival. Data collection is limited due to funding but the interest from both volunteers and the ever-growing tourism helps in the quest to inform conservation efforts.
Some issues of contention: turtle and egg munchers
One of the more debated threats to these conservation efforts I found, was the allowance of local indigenous harvests of both sea turtles and eggs for food and ceremonies. These rights have remained over time despite continual depletion of turtle population numbers and increasing pressure to retain species survival. Undoubtedly these harvests are not the most pressing of threats to population survival though continue to arouse debate around many of the public with interest in the marine conservation. Rights are exclusive to tribes associated with the area, though this eligibility is often difficult to prove, particularly in times with little visitation from researchers or public.
Some issues of contention: tourism
Another interesting and debatably threatening issue to conservation in the area, is the growing interest and funding for tourism on the island. Nearly every evening of my week-long trip, the island was visited by a small boatload of tourists, who would remain on the island for several hours to view available hatchlings and upcoming nesting females. This, importantly, sparks an awareness for conservation and a reasonable amount of tourist money contributes to Austurtle research (particularly through fundraising dinners), though large proportions of money are specifically used to fund the associated tourism businesses. These visits are not generally an issue, as most tourists are prepped on the appropriate behaviour to use around the turtles and supplied with red headtorches to view them. Turtle behaviour is generally associated with the lunar cycle, and they are attracted to bright light of the moon to navigate seaward. However, the use of occasional flash photography, fast movements and bright lights of tourism boats and tourist technology can seriously confuse and distress the turtles, and (critically) redirect both adults and hatchling turtles off their natural path to the water (as I noticed several times during my trip). In addition, any disturbance noted by a laying female may cause her to abandon the nest and often return to sea. Tourism impacts to the turtles are yet to be formally assessed, though it was one that concerned me several times during my volunteering, and will likely have more effect as the recreational attraction for the area grows.
Continuing the conservation: my Austurtle experience
Overall I had an amazing experience with the program and hopefully will make some small difference in providing the data needed to find conservation solutions. Hopefully with continued funding from volunteers and the public, this program may be extended to provide better management of threats and encourage the future survival of these wonderful Aussie turtles. This funding will be critical in the future conservation efforts of such programs, along with providing greater scientific research to address the impact of potentially risky issues such as tourism before they become problematic. Furthermore, I found volunteering to be a really profitable way to contribute to future conservation and feel so lucky to have been a part of it! Thankyou so much to my amazing research and volunteer team!
~ Alicia Palmer – u5520212