MUSSAU Island, New Ireland, is a remote island 160 kilometres to the north of Kavieng, well known for having a large population of green turtles. However, the disappearance of seagrass beds and an edible seaweed species (known locally as “goru”) has made locals concerned, with many suggesting the turtles are to blame because they eat both the seagrass and goru.
However, on-going investigations undertaken by Azalea Anota, a University of Papua New Guinea honours student, and Wildlife Conservation Society intern, as part of a project sponsored by the Critical Ecosystems Partnership Fund has found no link between turtle numbers and the disappearance of goru and seagrass.
Azalea points out that in her first sampling period at the village of Nae, in October 2016, turtles were only occasionally seen and there was almost no goru but by June 2017 there was a lot of goru and four times as many turtles. Azalea says that this pattern shows two things: goru can establish from near absence and take over a reef even when there are turtles in the area, and that high turtle numbers does not mean goru will disappear.
Additionally, her work is showing that turtles in the area are unlikely to be relying on goru and seagrass as a food given many more turtles can be found at her control site, which lacks goru and only has a little seagrass.
However, as to exactly what the turtles are feeding remains a mystery.
Azalea points out that it is very hard to observe a turtle underwater without disturbing them, and as a result it is very hard to know what they are feeding on.
Above water she has seen many turtles feeding on fallen leaves, a behaviour not previously recorded. Azalea suspects the turtles may be also be feeding on jellyfish and sponges, as they do in other parts of the world.
She also points out attitudes of locals towards turtles are changing as a consequence of the project, particularly in the village of Lolieng. Before the project began the community thought the turtles were damaging the coastal ecosystem and were planning to cull them.
She adds, “We are delighted that people of Lolieng decided to abandon the cull. The mass killing of turtles in such a hotspot could have been devastating for the regional turtle population. Not only that, but we are also heartened that the villagers are forming a community based organisation to support local natural resource management.”
- Story supplied by World Conservation Society, PNG.