Northwest Arkansas Democrat-Gazette
Snorkeling grandmas assist biologists in sea snake study
Just over 1,000 miles from the coast of Australia lies New Caledonia, an island archipelago where the waters teem with life. This French territory, in the heart of the Coral Sea, is home to more than 9,300 marine species, including dugongs, manta rays and venomous sea snakes.
Among them is the greater sea snake, which can reach nearly 5 feet long and is more than capable of killing a human with a single bite. But such a fearsome capability doesn’t bother Monique Zannier, 75, one of seven women, ages 6075, who snorkel regularly in Baie des Citrons, a bay in New Caledonia’s capital, Noumea.
“The Baie des Citrons is our playground,” she said. “We are in it almost daily, and we know all its nooks.”
What started as good regular exercise for Zannier has turned into a bounty of information for scientists studying the aquatic snakes. Researchers seeking new insights into the ecology of these reptiles have come to rely on the women, nicknamed the “fantastic grandmothers,” to help keep track of the hundreds of greater sea snakes that visit Noumea’s shallow-water bays.
An article published in October
in the journal Ecosphere highlights the fruits of this collaboration between the team of snorkeling, senior citizen scientists and the study’s lead authors, Claire Goiran, a marine biologist at the University of New Caledonia, and Rick
Shine, an evolutionary biologist at Australia’s Macquarie University.
Unlike their terrestrial cousins, sea snakes are largely understudied. Most sea snakes live far offshore and are dangerous to handle, so few scientists have the means or desire to study them.
“We know very little about sea snakes,” Shine said. “Almost everything we know about them comes from ones that were accidentally caught in fishing nets.”
In 2013, Shine and Goiran set out to learn what they could about the mysterious greater sea snake. They chose the Baie des Citrons as the venue for this study, despite greater sea snakes having been seen there only six times in the past eight years.
With limited time to survey the bay and no full-time volunteers to assist them, Goiran and Shine got off to a slow start. During the first three years of the study, the pair managed to catalog only 45 greater sea snakes.
But that all changed in June 2017 when Goiran met Aline Guemas, a 61-year-old retiree. One morning, while Goiran was snorkeling, she saw Guemas photographing the reef with her camera.
“We started chatting in the water, and I explained to her what I was doing and she told me she wanted to help,” Goiran said.
Guemas started joining Goiran on her weekly surveys, photographing sea snakes and recording their location on the reef.
Among the first to join the group was Zannier, who had taken up snorkeling as a form of physical therapy, as well as Sylvie Hebert, a 62-year-old retired nurse who has circumnavigated the globe by sailboat, and Marilyn Sarocchi, a 63-year-old gymnast with a fear of snakes.
Since the group’s inception, the “fantastic grandmothers” have conducted hundreds of snorkel surveys in the Baie des Citrons and identified hundreds of greater sea snakes.
“As soon as the grandmothers set to work, we realized that we had massively underestimated the abundance of greater sea snakes in the bay,” Goiran wrote in the study.
Photographs taken by the grandmothers demonstrated that, within a 25-month period, at least 140 greater sea snakes visited the Baie des Citrons.
The research suggested that greater sea snakes may play a larger role in the functioning of their ecosystem than previously thought.
The grandmothers say they have been able to find so many more snakes because, as retirees, they have more free time for the search than the researchers do.
However, Shine insisted that the grandmothers take more to the table than just their free time.
“They understand what we’re trying to achieve, and they put enormous effort into helping us achieve it, ” he said.