Turtle Talk

1. What would you say is the main cause of turtle populations becoming more and more dominated by females?

 

Climate change - warmer incubation temperatures generate more female hatchlings (temperature dependent sex determination)

 

2. In your opinion how much of a role does climate change play into the endangerment of sea turtles?

 

A very large role. Climate change was listed as the number one threat to sea turtles in the 2017 Report: Recovery Plan for Marine Turtles in Australia. 

There are many aspects to consider with Climate Change:
TEMPERATURE
With average global temperature predicted to increase 4.7 Fahrenheit (2.6 Celsius) by 2100, many sea turtle populations are in danger of high egg mortality and female-only offspring production.
STORMS
Predicted increase in the frequency and severity of storm events will increase the risk of eggs being inundated or completely washed away during incubation.
OCEAN ACIDIFICATION
This will affect the development of food sources for sea turtles, for example loggerhead sea turtles feed on crustaceans and mollusks which build a hard shell of calcium carbonate. These animals will not be able to grow a strong shell and therefore populations may be at risk. 
SEA LEVEL RISE
Similar to the increase in frequency and severity of storms, predicted sea level rise will result in more nests becoming inundated during incubation. 

The second priority in the report highlights the impact of marine debris - plastic pollution is affecting many marine animals at all stages of their lifecycle. Sea turtles are unable to regurgitate food, so if they ingest plastic it usually becomes stuck in their digestive system. 

 

3. What are the ideal breeding grounds for sea turtles?

Sea turtles return to the beaches from which they were hatched. Therefore, it is important that we maintain the existing rookeries. 
Nesting beaches are usually sandy to allow the turtles to construct and egg chamber, nesting beaches may be on the mainland or on islands. 
Ideally nesting beaches will be free from introduced predators (e.g. foxes, wild cats, wild dogs, wild pigs, raccoons) and with no artificial lighting on or near the beach. Artificial lighting and 'sky glow' has a huge effect on sea turtle nesting beaches.
 

4. How fast would you say this problem is leading to extinction? (at what rates)

This will vary between rookeries, as you need to consider the impacts of climate change in that area plus the impacts from other activities such as marine debris, artificial lighting, feral animal predators, etc. 
Irrespective of this local rate of chance, it is imperative that we take action now. 
 

5. Can this society dominated by females be prevented and brought back to normal conditions? If so, how?

This is definitely a challenge. Halting, or slowing down, climate change should be a priority for the entire world. In terms of local solutions, some nesting beaches remove the eggs from the sand and incubate them in hatcheries at set temperatures to achieve the desired male:female ratio. This can be done if the region has enough funding and resources. On larger rookeries however (eg Raine Island) it will be near impossible to collect all the turtle eggs, due to the large amount of sea turtles that nest on the island. 
Potential solutions could also include planting larger trees or erecting shade tents to decrease sand temperatures in the rookeries. 
 

6. Is anything being done as we speak in attempt to solve this problem?

On-going research into the predicted impacts of climate change, on-going monitoring programs on nesting beaches (including tagging and satellite tracking), conferences and working groups within government and across the world. Look up the International Sea Turtle Symposium - sea turtle researchers from all over the world regularly come together to discuss current research. In Queensland, the main entities working with marine turtles include the Queensland Parks and Wildlife Service, Great Barrier Reef Marine Park Authority and universities including University of Queensland and James Cook University.