Is climate change really good for sea turtles?

(You may have read in recent news that climate change may increase the size of some sea turtle populations, by increasing the number of female turtles.

These studies are based on a unique feature of sea turtles: their sex is determined by the temperature in the turtle nest . Turtles hatched at temperatures above 29 ^o C expand most females, while temperatures below 29 ^o C will expand mostly male turtles.

Recent research by scientists published in the journal Natural Climate Change (Nature Climate Change) has found, by influencing the sex ratio of turtle populations towards a large Children, climate change can lead to an increase in turtle populations in the short term . But this is not the whole story.

Warmer turtle eggs have more female turtles

The study found that increased temperatures could alter the sex ratio and increase the size of some species of sea turtles.

Sea turtles are strange because the sex of baby turtles is determined not by sex chromosomes (as in the case of humans and other mammals), but by incubation temperatures , one present. The phenomenon is known as temperature-dependent sex determination .

Exceeding a critical incubation temperature is 29 ^° C, usually sea turtle eggs hatch offspring, and vice versa. This key temperature is shared with many species of sea turtles and may have evolved to create the optimal sex ratio.

So warm temperatures can lead to 'feminization' of sea turtle populations by only hatching female turtles. Previous studies have highlighted that, all other factors are equal, this 'feminization' can influence the destruction of populations.

However, while the threat of 'feminization' of sea turtle populations has been known for many years, little effort has been made to predict the future sex ratio of populations that may change as how, and the risk of extinction.

The study was carried out by an international team of scientists from Deakin University in Warrnambool (Australia) and Swansea University (United Kingdom) who performed at one of the beaches with many sea turtles laying The largest eggs of the world, Cape Verde Islands in the Atlantic Ocean, where a large number of caretta turtles breed. The sand temperature on nesting turtle beaches spawning eggs has been recorded over the years with compact temperature data collection sets.

Then the temperature records of sand will be combined with assessments of past environmental conditions on these islands from 1850, and climate projections for the next 100 years to be carried out. by the IPCC organization (Intergovernmental Panel on Climate Change). In this way, a 250-year time series of incubation temperatures, turtle sex ratio and sex ratio of adult turtles were established.

The study found that rising temperatures could lead to an increase in the number of females of sea turtles, but the whole 'feminization' would not happen in the next few decades. In fact, warmer tortoise hatching temperatures can provide a short-term benefit to preserving turtles, increasing the number of female turtles and thereby increasing the overall size of the sea turtle population.

Climate change is still unfavorable for turtles

However, research has not ended. There is a lot to do to find out how sea turtles will be affected by climate change.

This study focuses on a position in the Atlantic Ocean. Research is needed to consider the threat of ' feminizing ' sea ​​turtles in many of their other spawning sites around the world, including the area around Australia's coast, which is home to Key populations of some species.

By expanding these analytical methods, scientists can identify areas where climate change and the 'feminization' of populations are the most severe. In this way, scientists can give an early warning to areas where future management interventions are needed, such as in the form of a turtle nest to ensure that The hatched turtle will be a male turtle.

Moreover, when the number of male turtles decreases, they will become more important but we know very little about male turtles. Unlike females, male sea turtles do not go ashore and therefore it is difficult to study them. While thousands of adult female turtles have been tagged with satellite tags, only a handful of adult male turtles have been tracked.

There is an important gap between understanding turtles and male turtles. We have begun to close this gap by catching male sea turtles and tagging them. In this way, scientists will gain more data about males. The findings of this study show that the sex ratio of gender bias is actually transformed into a more balanced sex ratio of males and females. Many studies of reproductive intervals need to be done on different species and at different breeding sites.

Therefore, while recent studies provide some useful insights on how climate can affect sea turtles, a series of questions still need to be answered. Predicting that, in the long term, climate warming is not a good thing for sea turtles.