This Conservation Method May Be Negatively Affecting The Development Of Sea Turtle Hatchlings

Babies are fragile creatures. Any newborn creature is soft, in every sense of the word. And newborns bring out the intense need to protect.

Sea turtles have always been subject to wildlife conservation projects. Six out of seven sea turtle species are listed as endangered, and three of which are considered as critically endangered. These species are all victims of marine pollution, habitat destruction, poaching, and, as always, climate change.

PHOTO: Wikipedia/Sébastien Stradal for MDC Seamarc Maldives

Turtle eggs are always in anger as these creatures are buried in beaches, susceptible to predation from other animals and even humans, and human activities have directly destroyed or disturbed sea turtle nesting beaches around the world, according to WWF.

Some organizations have made it their duty to protect the turtle species from extinction by moving turtle eggs from their natural birth place, gathering them from beaches and moving them to the safety and stability of well-maintained hatcheries.

Projects like these manage to give the eggs a safe space to hatch, they do protect the species, but a recent study found out that this off-site or ex situ incubation, as The Scientist said, can have a negative effect on the development of the turtle hatchlings.

PHOTO: Unsplash/Daria Gordova

The research team studied 10 Olive Ridley (Lepidochelys olivacea) nests, one of the two sea turtle species that isn’t endangered and is considered as the most abundant of all sea turtles, for their study. The research team thinks that although they selected just one species to study, Esperanza Meléndez-Herrera, co-author of the study said, “we think that our results can be applied to all sea turtles.”

Half of the nests were left incubating on the beach, while the other half was moved to a hatchery. When the turtles hatched, the researchers picked five females from each nest and proceeded to weigh and measure them. They collected the data and found that the hatchlings left on the beach are heavier and longer than the hatchlings they moved for an ex situ incubation.

Aside from the physical differences between the two groups, the research team also delved into the neurogenesis of the two groups. They found that the in situ group had averagely around 813 more developed neurons than those who were moved to the hatchery. These neurons are found in the dorsomedial and medial cortices of the hatchling’s brain which are said to have roles on an individual’s learning and memory. According to the article, early poor environmental conditions can result in long-lasting brain alterations which will then cause the turtles to have anxiety or depressive-like behaviors.

Moving on to the effects on ovariogenesis in the hatchlings, the ex situ hatchlings’ ovaries are found to have a lesser number of proliferating cells.

Lastly, the researchers said that fitness in the female hatchlings are also negatively affected by ex situ incubation. Compared to the in situ hatchlings, the ex situ clutch had slower self-righting time. They measured this by placing the hatchlings upside down in a tray of sand and recording the self-righting time, the in situ clutch were able to turn themselves over 5.49 seconds faster on average.

“In almost everything we measured, the turtles from artificial nests were much worse,” said Bryan Phillips-Farfán, co-author of the study. “So maybe, yes, we’re sort of saving them from many threats, but at the same time, we’re sort of hindering their development.”

The scientists didn’t exclude the possibility of other factors like temperature and moisture to affect their results, they suspect that these factors played a larger role in their recorded results, they said. A biologist not involved in the research, Rick Herren, provided his opinion on the research and said that the “environmental differences between the treatments may have influenced the differing growth patterns, and that it was likely the egg microenvironment rather than the act of moving that led to divergences in the tested variables.”

Another biologist who reviewed the research, Jeanette Wyneken, and is an expert researcher on sea turtles said that although the article provided data that showed the difference between in and ex situ growth, it didn’t prove that the negative effects will remain with the turtles as they age.

Herren, who is also a project manager at the Sea Turtle Conservancy, commended the study and said that it is “important in that it adds further evidence of the potential detrimental effects of putting nests in hatcheries and suggests future research on embryonic development and the nest micro-climate.”

Herren said that even with this current research, moving nests can be better than the alternative. He added that he directed past projects that had them moving nests on beaches rather than on hatcheries, which resulted in a disappointing ending. “Those eggs were deemed unlikely to survive if they were left because of erosion, beach traffic, nest predation or beach construction,” he said in an email to The Scientist.

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