September 12, 2024

Participating in the loggerhead turtle survey in Kishu Minabe, NYK (sea turtles talk about tears)

Starting Sunday, July 21st, 2024, we
have been given the opportunity to participate in a volunteer survey sponsored by Nippon Yusen in Minabe Town, Wakayama Prefecture, with the cooperation of the Japan Sea Turtle Council (Chairman Matsuzawa Keimasa). I will report on this situation.

Volunteering is tough

Professor Matsuzawa gave us a lecture on sea turtles and sea turtle conservation activities in Minabe town, and we finally got to support the research in the evening. They are divided into two beach groups and first head out to the sea to find a landing of sea turtles. Our Chirihama group takes an hour shift from 8pm to 2am to 2am, and will patrol the coast of Chirihama, which is approximately 1km long. Walking along the beautiful coast of a full moon looking for turtle footprints. On a hot sauna-like night, I walked, being caught in the soft sand. There's no time to enjoy the beautiful ocean, and it's really tough. On the first day, a group from Iwashirohama, the beach, was able to install a transmitter for each horse. Our Chirihama group found landing marks. However, although they landed, they didn't lay eggs and left. It is speculated that he was scared of the lights on trains and cars. It's delicate, isn't it? On the second day, we were able to install a transmitter on a new horse at Iwashirohama. It was said that this individual may have returned to birth on the first day at Chirihama.

Loggerhead turtle moms are tough

Here we will introduce you to the logged sea turtle that we learned from our teacher.
Loggerhead sea turtle (Caretta caretta)

is an endangered species, and has been decreasing sharply in recent years. A carnivorous person who mainly prefers beneficial organisms (shellfish and crustaceans) (green sea turtles are herbivorous people, such as seaweed and seaweed). There is no magnitude, so you can dive to about 200m at depth by pulmonary breathing for two hours. The lifespan is estimated to be 70 to 80 years. In the East China Sea, food is reduced due to the increase in bottom trawling fishing, and many individuals are forced to wander around the ocean, where food is scarce. His natural enemies are orcas and sharks. The spawning sites are Japan and Jeju Island in the North Pacific, but Jeju Island has not even been confirmed to have landed since 2007. Marine plastic waste has been found in Florida in 93% of sea turtles. However, most of the cases are not digested and excreted from the body. It has a powerful geomagnetic compass and is estimated to be able to sail fairly accurately while also looking at the position of the sun. The sex of a sea turtle is determined by the temperature at which the egg is. Males are born when the sand temperature is below 29°, and females are born when the sand temperature is above 30°. As global warming progresses, the eggs start to die, and at a temperature of 33°, the eggs die. Females can only ovulate after preparing their eggs and mating. We were shown a GPS track map of an individual who was suspected to be unable to meet a male and was stumbling around Osaka Bay. It may be that the number of males has already begun to decline. Recently, the oceans are becoming more severe, and it seems that eggs are often washed away due to high tides and high waves. The line of vegetation on the sandy beach is a sign that prevents high waves from coming in. The mother turtle is inevitably trying to climb the dunes. His intense breathing stuck in my ears.
　
On average, sea turtles can mature sexually at around 40 years old and become adults and breed. The current impact of global warming will also become more pronounced in 40 years. I was surprised at how delicate it is.

Not only this, but artificial objects (for example, fishing port maintenance) can steal the beach, problems with light pollution (hatched turtles recognize the direction of light as the sea. Light from trains, cars, and towns is illusionally the light of the sea, and they go in the opposite direction to the sea and die. Mother turtles hate light and are unable to land), and other things that can be entangled in fishing nets and drown.
　
Sea turtles also seem to have an important role in transporting sea nutrients to land. Realistically, even if only about half of the eggs can hatch, about two-thirds of the total can be used in the eggs and the eggs that were unable to hatch, about two-thirds of the eggs are nutrients for land living things. Sand beaches are a poor nutritional environment. Turtles support this vegetation with nutrients, and the plants play a major role in maintaining the sandy beach. It was said that stability on sandy beaches is extremely important in terms of maintaining the beach and in terms of ecosystem health. Maintaining ecosystems is also a harsh reality. As a result, it was said that sea turtles' landings and egg-laying have been decreasing dramatically even in Minabe Town.

It's tough for bees too

Meanwhile, in Minabe Town, the Minabe and Tanabe plum system is registered as a World Agricultural Heritage Site. The forests of the Satoyama produce Kishu binchotan charcoal, and the plum forests cultivate high-quality plums, have rich rice fields, and protect the vegetation and environment behind the coast. Healthy agriculture and forestry are the core industry of the town, and we are building a town that does not use sea turtles as a tourist resource. The town has a strong understanding and support for research on sea turtles, and the support of young people is also active, making it a kind and wonderful town.

However, this year's plum blossoms were said to be a "massive crop" that has not been seen in recent years. The considerable warm winter has caused the bees that pollinated pollination to be inactivated, and pollination has not been carried out at all. There is also concern about the effects of global warming here as well.

It's really tough to be faced with such a treat!

By the way, the food in this program is very tasty. However, in front of this very treat, there was no beer there, so we headed out for a late-night meal in about 30 minutes. All-you-can-eat pickled plums, a specialty of Minabe!　

 Me

Sea turtle research has no direct impact on the company business or the economy. However, although he may seem cheeky, I think what we have learned through basic biology research will tell you about the reality of global environmental issues. There is still so much we don't know about. Through research into sea turtles, I once again realized that there are many "important insights and learnings" there are. I felt that research and support for such research is very important. Ecosystems are delicate, and I learned that even a temperature of 1°2° has a huge impact. On the other hand, one transmitter attached to sea turtles is apparently $4,000. I learned that researchers and volunteers are also very burdensome in labor and research costs. We hope that the survey of loggerhead sea turtles in this Minabe will continue, research results will be improved, shared around the world, and support from the Nippon Yusen Group will continue. We hope that our employees will participate in the next year as well.

At the seminar compiling the final day, we all named the loggerhead turtle this time. From now on, data from the transmitter will be tracked and accumulated under this name. The child on the first day was named "Runa-chan," after a full moon night, and the child on the second day was named "Tae-chan." Tae-chan's shell had marks of being bitten by a shark, so it was a sign of her desire to endure the difficult journey, and to lay eggs well, and to endure the work of installing the transmitter after spawning.

Good luck, everyone, Runa-chan, Tae-chan, and Minabe!

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