One for hundreds. Sea turtles may become extinct due to lack of males
November 22, 00:23 Share:
Green sea turtles may become extinct due to lack of males (Photo: Brocken Inaglory / Wikipedia)
Green sea turtles (Chelonia mydas) are endangered. In addition to reasons directly related to human activity, less obvious ones also led to this: lack of males and toxins.
This species of turtle suffers from people collecting their eggs and producing trash that ends up in their habitat.. But besides these reasons, another one led to their possible extinction – a significant sexual imbalance, which can be enhanced by substances that pollute water bodies. says a study published in the journal Frontiers in Marine Science.
Green sea turtles inhabit tropical, subtropical and temperate regions of the Atlantic, Pacific and Indian Oceans, as well as the Mediterranean Sea. And everywhere they fix the same problem: a significant predominance of the number of females in the population.
This was previously explained by the fact that the sex of a green sea turtle embryo is determined by the temperature of the sand around the egg.. Females have an advantage due to global temperature rise. In some warm places, such as the northern Great Barrier Reef, there are already hundreds of females per male.
But scientists have found that, in addition to temperature, the feminization of the species can be facilitated by heavy metals and organic substances that enter the oceans as a result of human activity – from mining to dumping household waste into water bodies.
“Our study suggests that the risk of extinction due to a shortage of male green sea turtles may be exacerbated by pollutants that may also affect the sex ratio of green sea turtle development,” said toxicologist and lead study author Arthur Barraza in the paper.
Female turtles accumulate these substances in their bodies and eventually pass them on to their offspring.. They can remain in the animal's body for years after hatching. To assess the scale of the problem, scientists sampled 17 clutches of green sea turtle eggs on an island on the Great Barrier Reef and measured indicators such as temperature inside the nest and on the beach surface, and the content of pollutants in the body. The researchers found a connection between the level of contaminants in the hatchlings' livers and how many females were in the nest.
The scientists note that more research is needed to determine whether these pollutants actually contribute to differences in sex ratios, but the finding is already concerning given the current shortage of males.
“ Identifying which specific compounds can alter the sex ratio of hatchlings is important for developing strategies to prevent further feminization of sea turtle populations due to pollutants,” said study senior author Jason van de Merwe, a marine ecologist at the Australian Rivers Institute.
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