For these critically endangered marine turtles, climate change could be a knockout blow

December 14, 2018, Florida State University

Hawksbill turtles aren't the only marine turtles threatened by the destabilizing effects of climate change, but a new study from researchers at Florida State University shows that this critically endangered species could be at particular risk.

In a study published in the journal PLOS ONE, researchers from FSU's Department of Earth, Ocean and Atmospheric Science suggest that projected increases in air temperatures, rainfall inundation and blistering solar radiation could significantly reduce hawksbill hatching success at a selection of major nesting beaches.

Earth's history abounds with examples of climate shifts, but researchers say today's transforming climate, paired with unabated human development, imperils hawksbills and other marine turtles in new and alarming ways.

"Marine turtles have been around for millions of years, and during this time they have adapted to substantial climatic changes," said Assistant Professor of Oceanography Mariana Fuentes, co-author of the study. "In the past they have adapted by shifting their nesting grounds and nesting season to align with more favorable conditions. However, increasing impacts to nesting habitats from coastal construction, storms and sea level rise are jeopardizing their ability to adapt."

To evaluate climate change's effects on hawksbill hatching success, FSU researchers analyzed more than 5,000 nests from the five Brazilian beaches where a majority of the region's hawksbill nesting occurs. The team focused specifically on five climatic variables—air temperature, rainfall, humidity, solar radiation and wind speed—in order to render a more comprehensive model of the various and subtle effects of a changing climate on the sensitive incubation process.

"Research is lacking on how climate change may influence hawksbills, and this population in particular," said former FSU graduate student Natalie Montero, who led the study. "We chose to study how climate change may impact hatchling production because significant changes to how many baby marine turtles are born can dramatically alter population stability."

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Hawksbill turtles' monogamous sex life revealed

By Michelle Warwicker, BBC Nature

The sex lives of critically endangered hawksbill turtles have been revealed by scientists studying the animals in the Seychelles.

Previously, little had been understood about the mating habits of the turtles, which live underwater and often far out at sea.

Researchers were surprised to find that the turtles are mainly monogamous, with females storing sperm from one male and using it to fertilise multiple egg clutches.

The study, led by researchers from the University of East Anglia, Norwich, UK, was published in the online journal Molecular Ecology.

"Sperm storage" is found in animals including reptiles, birds and some turtles, tortoises and terrapins.

Females can store viable sperm from multiple males for long periods of time, meaning that their egg clutches are sometimes fertilised by more than one father.

Researchers carried out DNA testing from hawksbill turtle hatchlings on Cousine Island in the Seychelles to identify how many males were involved in fertilising eggs during a breeding season.

The tests revealed a monogamous mating system: most egg clutches were sired by just one male, and no males had fertilised more than one female during the 75-day season.

Read more:  http://www.bbc.co.uk/nature/21261584

Working to save Nicaragua’s hawksbills

January 2012: Estero Padre Ramos is recognised as a globally important site for the Critically Endangered hawksbill turtle. Located in northwest Nicaragua, it is a shallow marine estuary comprising lagoons, inlets, beaches and mangroves. For more than five years, community leader Luis Manzanares has been working to protect sea turtles in the area and now runs the Proyecto Carey hawksbill turtle conservation project which is supported by Fauna & Flora International (FFI) and the Eastern Pacific Hawksbill Initiative (ICAPO). The project has now completed its second season - here Luis shares the results...

More than 11,500 hatchlings successfully released

This year the field team built a hatchery to protect relocated turtle eggs, as well as an experimental hatchery to test the effects of different environmental conditions on hatching success.

Nightly beach patrols took place from May to October last year along three miles of beach and an exchange visit took place with its ‘sister' hawksbill project at Bahia Jiquilisco in El Salvador.

‘This initiative is helping local people meet their daily subsistence needs, providing vital income to improve their diet, diversify their crops and support their families,' says Luis.

By the end of the 2011 nesting season, the project team had recorded 150 hawksbill nests, tagged 32 nesting females for future identification, and successfully released almost 11,500 hatchlings to the sea.

Over the two seasons of the project, 90 per cent of nests recorded have been successfully protected, a strong indicator of the ‘buy-in' from local community members and stakeholders (in comparison, it is estimated that all nests were illegally poached prior to 2010).

Luis concludes: ‘The community is happy that Estero Padre Ramos is known worldwide for its number of hawksbill turtles and people now have hope that in future years their numbers will increase and our children will have the opportunity to know them.'

Despite the 2011 hawksbill nesting season drawing to a close in October, FFI's specialist turtle teams in Nicaragua, led by José Urteaga, Perla Torres and Gena Arbarca, are kept busy throughout the year. Marcial Chàvez is a local community leader involved in monitoring olive ridley turtle arribadas in the Chacocente Wildlife Refuge, where FFI has been working for ten years.

During that time between 30,000 and 60,000 olive ridley nests have been recoreded each year at this beach alone, resulting in many millions of olive ridley hatchlings returning to the sea (more than 1.5 million in the 2010-11 season - this year's data is still being collated!)

This season, Marcial and his team have recorded five arribada mass nesting events at Chacocente since July, each involving between 2,000 and 20,000 nesting females, alongside smaller-scale nesting activity.

Marcial works closely with FFI to reduce the plundering of turtle eggs from the arribada beach and strengthen turtle-friendly economic alternatives through rural community tourism.

500 leatherback nests protected

As for the majestic leatherback turtle - the original flagship species of FFI's turtle conservation programme - FFI now supports conservation activities at three of the most important nesting sites for leatherbacks along Nicaragua's pacific coast.

Since FFI's pioneering leatherback conservation work began, more than 500 leatherback nests at Chacocente, Isla Juan Venado and Salamina have been protected. Juan Manuel, is a community leader involved with FFI's leatherback turtle conservation project at Chacocente.

‘My hope is that in 20 years' time we will witness the return of some of the leatherbacks I have seen hatch out in the nursery and be released into the sea over the past ten years,' he says. ‘I will then feel satisfied to have contributed to the recovery of this species.'

http://www.wildlifeextra.com/go/news/nicaragua-turtles.html

'Hidden' hawksbill turtles found (via Dawn Holloway)

Scientists have found hawksbill turtles "hiding" in mangrove forests of the eastern Pacific.

The team, that has been tracking the turtles for three years, also found that the critically endangered animals nested in these estuaries.

The discovery of this previously unknown sea turtle habitat was published recently in the Royal Society journal Biology Letters.

It could explain why the species went undetected in the region for so long.

Mangrove forests, which are unique coastal tree and shrub habitats, are also under threat. They could represent an important breeding and nesting site for the species, which was thought to depend on coral reefs.

Alexander Gaos, a conservation scientist with San Diego State University and the Eastern Pacific Hawksbill Initiative, led the research.

He and his colleagues tracked hawksbills in four countries - El Salvador, Honduras, Nicaragua and Ecuador - using satellite tracking tags glued to the turtles' backs.

These trackers revealed that adult hawksbill turtles in the eastern Pacific inhabited in-shore mangrove estuaries.

"For upwards of five decades sea turtle scientists thought hawksbills had [disappeared from] the eastern Pacific Ocean", Dr Gaos told BBC Nature.

"Despite hundreds of sea turtle projects and scientists focusing efforts in the region, no one had located hawksbills.

Our findings help explain this… it's hard to spot hawksbills in mangrove estuaries."

Dr Gaos said that the turtles might be spending their entire lives in these "cryptic habitats".

"Couple that with the fact that there are very few individuals left - hawksbills in the eastern Pacific are one of the world's most endangered sea turtle populations - and it's no wonder researchers didn't know about them!"

The scientists worked with local fishermen and even illegal egg collectors, in order to find hawksbill turtles to fit their tags to.

They hope their revelations about the species' habitat will inform conservation efforts.

Why the turtles were "seeking shelter" in mangroves was not clear.

The scientists think it might be a recent adaptation brought on by a lack of their more typical habitat of coral reefs in the region.

Dr Gaos said: " We now have a better idea of where to look for them, which may help us direct research and conservation of the species, upon which their survival may ultimately depend."
By Victoria Gill Science reporter, BBC Nature
http://www.bbc.co.uk/nature/14735144