On November 1, the Philippine National Police Maritime Group helped in successfully rescuing and releasing back into the wild a nesting green marine turtle that was trapped under a small seaport in Barangay Taganak in the Turtle Islands in Tawi-Tawi, a known green marine turtle nesting ground.
Incidents like this are bound to happen as marine turtles, locally known as pawikan, struggle to survive the impacts of destructive development activities and human encroachment of their wildlife habitats, which are being aggravated by severe climate change.
As world leaders contend on the issue of limiting to 1.5 degrees Celcius the increase in global temperature at the conclusion of the 26th Conference of the Parties (COP26) meeting in Glasgow, the severe effects of climate change is already being strongly felt in coastal communities.
Marine turtle country
The Philippines is known to host to five out of the seven known species of marine turtles, whose ecosystem functions are crucial in maintaining a balanced marine ecosystem.
The green and live ridley turtles are the most common nesters in the country, followed by the hawksbill turtles.
The leatherback turtles are also known to nest in the Philippines, while there is still no record of the loggerhead species nesting in the country.
Being host to thousands of nesting marine turtles, particularly in the Turtle Islands Wildlife Sanctuary in Tawi-Tawi, the Philippines is in a unique position to save this endangered species from extinction.
Scientists believe they have evolved as they learned to adapt and survive for millions of years despite global climate events.
With the Philippines being a country most vulnerable to climate change, can these mysterious creatures of the sea survive this time around?
Sea level rise
“Definitely, climate change has a huge effect on marine turtle population. Because of climate change, sea level rises, thereby, destroying their nesting grounds,” said veterinarian Aracelli Salinas, the leading authority on marine turtle conservation at the Department of Environment and Natural Resources-Biodiversity Management Bureau (DENR-BMB) told the BusinessMirror on November 10.
“Once the marine turtles are able to find a new nesting ground, the effect of temperature increase affects the development of the eggs,” Salinas added.
She said sea-level rise and storm surges that threaten communities due to extreme weather events attributed to climate change compel communities to implement measures like the building of sea walls that aggravate the problem.
This can be observed in many parts of the country with the development in coastal areas and the establishment of more beach resorts to accommodate tourists.
Asean Centre for Biodiversity (ACB) Executive Director Theresa Mundita S. Lim added that sea-level rise can have an adverse effect on the survival of marine turtles even after hatching.
She explained that marine turtles lay their eggs in dry sand, which they can easily dig into, and where the hatchlings can also easily dig out of, to emerge.
“Sea-level rise will affect this, because the beaches, where the females will need to lay their eggs, will become submerged. So say, even if there are still a few males to fertilize the females’ eggs, there will eventually be no suitable place above the shoreline for female turtles to deposit their eggs,” Lim said.
‘Warmer temperature yields more female turtles’
The warming of global temperature also has an uncanny way of affecting marine turtles.
Unlike most sea creatures, temperature affects the development of marine turtles while inside the egg.
Lim, interviewed by BusinessMirror on November 1 via Messenger, said there were studies on the marine turtle eggs in Turtle Islands that proved that the sex of the marine turtles is determined by temperature.
Lim started her career as a veterinarian working under the Pawikan Conservation Project in Tawi-Tawi. She said even before climate change was seriously considered a threat to biodiversity, the scientists, as well as the DENR-BMB’s own study, were already alarming marine turtle conservation workers.
“Warmer temperatures [around 31 degrees C] of the sand would yield more female hatchlings, and cooler temperatures [around 27º C], more males. From this data, we can already gather that with rising temperatures, the sex ratio in marine turtles will be affected,” Lim said.
According to Lim, eventually, there could be lesser males than females, and the breeding capacity will be reduced due to warmer temperatures.
Another adverse effect of climate change, ocean acidification will affect the food chain as planktons and shellfish that serve as part of the diet of marine turtles will be depleted.
“All these climate-related impacts will affect migration patterns and the survival of our marine turtles,” Lim said.
Arnel A. Yaptinchay of the Marine Wildlife Watch of the Philippines (MWWP) said it took marine turtles million years to adapt and survive dramatic climatic changes. This time, however, the catastrophic effect of climate change may be too severe that marine turtles will not be able to adapt and survive.
He said that in the marine turtles’ feeding area, depending on the species, corals may die, and cause the plankton, and even the fish and other marine life, to vanish.
“Each and every aspect and life phase will be affected negatively. While climate change will have a positive effect on some species, it might not be the same for marine turtles,” he explained.
“As food becomes unavailable in one area, they will naturally go to an area where there is abundant food for them to survive,” said Yaptinchay, whose organization rescues and saves marine wildlife.
Elson Aca of Balena.Org, who conducted a vulnerability assessment of marine turtles’ nesting sites in the Philippines, said the intensity of typhoons can also adversely affect the population of marine turtles.
“Today, typhoons are so intense that it can affect coastal areas. Typhoons can wash ashore nesting areas and destroy other ecosystems like seagrass and corals,” said Aca, who conducted the study as part of his dissertation for his Master of Science in Environmental Management.
“The thing is, they [marine turtles] were able to adapt to changes before. But with the rate of change in climate, how can marine turtles adapt now?” he asked.
The anthropogenic or environmental threats, due to climate change, Aca said, is aggravating the situation, further affecting the population of marine turtles.
Saving marine turtles
Lim said although climate change can affect marine turtle populations, addressing the direct man-made threats to them and to their habitats and feeding areas can also contribute to climate mitigation and as adaptation measures.
“So far the most obvious causes of mortalities are still pollution and marine plastics. These are the direct threats,” she said.
She pointed out that more studies would have to be undertaken on the migration patterns of marine turtles and, in the long term, to observe for changes to help address the problem.
For her part, Salinas said the DENR-BMB is already working with marine turtle hatchery managers in various parts of the country to manage the ratio of male and female marine turtles produced in controlled areas.
Trained managers of marine turtle hatcheries monitor the temperature of nests, both inside and outside, and put shades in some of the nests in the hatchery, she said.
Moreover, Salinas said the DENR-BMB has come up with guidelines on the declaration of marine turtle nesting grounds through BMB Technical Bulletin 2020-05 issued on November 20, 2020, by then-DENR-BMB Director Ricardo L. Calderon.
Declaring an area as a marine turtle nesting ground and establishing hatcheries in partnership with local government units, she said, is crucial to saving the marine turtles from extinction.