A study is now underway in Fiji to determine how climate change will impact the nesting sea turtle populations of Fiji

Scientists are concerned that human-induced climate change is causing an increase in the number of female marine turtle hatchlings, leading to a decline in the overall population due to the lack of male production.

This process, known as feminisation, occurs as the sex of a marine turtle embryo is determined by the temperature of the nest in which the eggs incubate. Warmer sand temperatures (>29°C) produce mostly female hatchlings, whilst cooler temperatures produce predominately males (<29°C). Identifying marine turtle nesting areas that may be feminising and require sand cooling intervention has become a priority for researchers in the low latitudes of Asia-Pacific. 

A study is now underway in Fiji to determine how climate change will impact the nesting sea turtle populations of Fiji. Fourteen temperature data loggers and a weather station have been deployed on Katawaqa Island off Kavewa village in the far north of Vanua Levu in Fiji’s Macuata Province. The island is one of Fiji’s key nesting sites for the critically endangered hawksbill turtle (Eretmochelys imbricata). Nest sand temperature, along with other weather variables, such as rain, is being measured to help determine how populations of marine turtles are being impacted by rising sand temperatures associated with human-induced climate change.  

The World Wide Fund for Nature Pacific office (WWF-Pacific) is leading the study with the support of the Secretariat of the Pacific Regional Environment Programme (SPREP) By-catch and Integrated Ecosystem Management (BIEM) Initiative. The BIEM Initiative is a key result area 5 of the Pacific-European Union Marine Partnership (PEUMP) programme, which is funded by the European Union and the Government of Sweden. This study is part of the greater Turtle Cooling Project led by WWF-Australia in collaboration with the University of Queensland and other partners to identify at-risk feminising nesting beaches across Asia-Pacific, determine how many breeding males are required to maintain a stable population, and to provide on-ground sand cooling solutions, such as irrigation, to increase male production.  

“This is a significant first for turtle research in Fiji and across the region, as we have not used long term temperature data logging instruments in previous studies, instead we’ve relied on observations and immediate hands-on measurements to monitor climate change impacts to turtle populations,” says Duncan Williams, Sustainable Seafood and Fisheries Programme Manager at WWF-Pacific. 

The temperature loggers are small devices buried in the sand at different depths and will continue to record daily temperature over a 12 month period, which includes one full nesting season. The weather station will record wind speed, temperature and pressure and rainfall at the site. It has been installed in the Kavewa community and the data will be downloaded at 4-monthly intervals  if conditions allow and cross-checked with information from the closest meteorological station.

Katawaqa Island is one of three locally important nesting sites of the hawksbill turtle in northern Fiji, with more than ten hawksbill turtle nests recorded there in the past, owing in part to the characteristics of the island. Katawaqa is a rather idyllic, uninhabited atoll with shade-giving trees in the centre, encircled by a raised and sloping white sandy beach. To date, we do not know the sand temperature profile of the beach and whether feminisation is an issue. There may be sufficient shade for most nesting areas of the island however, a recent beach erosion study by WWF-Pacific on three nesting islands, Yadua, Kia and Katawaqa, found that the beaches have already retreated by at least 10 metres over a four-year period. As the island is similar to the other important hawksbill nesting beaches in Fiji, this project will be crucial to understand if Fiji is at-risk of a feminising population and where best to put its efforts to support future sand cooling effort and interventions.   

The community of Kavewa Island has been involved in turtle conservation and research with WWF-Pacific since the early 2000’s. One of the challenges for turtle conservation research is that the nesting season coincides with Fiji’s cyclone season (November to April). Two tropical cyclones – TC Ana and TC Yasa – resulted in delays in installing the instruments earlier in the 2020 nesting season. 

“The village of Kavewa was severely affected by the cyclones and needed assistance with rebuilding,” explains Jamie Davies, Manager of the SPREP BIEM Initiative. 

“Unfortunately, when we thought the people of Kavewa were ready to be involved in deploying the data loggers, COVID related travel restrictions then came into place, meaning that the WWF-Pacific technical team based in Suva, a COVID contained zone, could not visit Kavewa to deploy the loggers.” 

The BIEM Initiative Fiji country coordinator, Kelera Macedru, who happens to be based in Vanua Levu, was able to step in – a request that required very little prompting! Macedru embraced her unexpected task with enthusiasm and, with online guidance and training provided by Turtle Cooling partner and PhD candidate, Melissa Staines, she familiarised herself with the equipment and installation process. 

The installation of the mobile weather station and the temperature loggers was achieved over a two day period from 23 to 24 June 2021, following the strict requirements of ensuring the location of the loggers using a GPS location device and setting up control sites. 

When asked to describe her experience of the activity, Macedru said “I am delighted to be a part of this activity and to enable the installation of this important research equipment. It was a valuable opportunity for me to meet the Kavewa community and to get an appreciation of their island.” 

She also acknowledges the knowledge of Emosi Time, the Dau ni Vonu or turtle monitor and protector. 

“We were almost fully reliant on Emosi’s understanding of turtles and their behaviour,” she says. “Once on Katawaqa Island, we needed his guidance as we set about installing the temperature loggers.”

Silibaravi was once a traditional turtle hunter but has turned his skills to protecting what he sees as the heritage of his people. 

Jamie Davies, BIEM Initiative Manager, says “Despite the hitches caused by travel restrictions due to COVID, we are glad to have found a workable solution that will allow the planned turtle assessment work to progress.

“The urgency of understanding and addressing climate change impacts remains a constant even during this pandemic, and we do our best to progress the all-important conservation and species management work in collaboration with our implementing partners and local communities,” he said. 

Funded by the European Union and the Government of Sweden, the EUR 45 million PEUMP programme promotes sustainable management and sound ocean governance for food security and economic growth, while addressing climate change resilience and conservation of marine biodiversity. It follows a comprehensive approach, integrating issues related to oceanic fisheries, coastal fisheries, community development, marine conservation, and capacity building under one single regional action. SPREP is leading Key Result Area 5 of the PEUMP programme, the BIEM Initiative, to support the governments of Fiji, Papua New Guinea, Solomon Islands, Tonga and Vanuatu in the sustainable management of coastal and marine biodiversity.

This story was written by Leanne, originally published at SPREP on 26 May 2022, reposted via PACNEWS.